How can I learn to sprint and ride out of the saddle?

If you want to improve balance and control out of the saddle at any speed, even freewheeling, you just have to practice doing it.  Note that balance while pedaling out of the saddle on a trainer vs. on the road will be very different as the bike is held firmly upright in the trainer

With respect to power output: pedaling out of the saddle is usually done for a short burst of power against a high resistance with a low cadence - either up a short steep slope or accelerating in a too high gear. Pedaling at a sitting cadence while standing up will be quite inefficient.

Basically, you have to get the gear ratio selection right to enable max power output. Lower for in the saddle, higher for out of the saddle.

Edit:

You might want to experiment with how forward or back over the bottom bracket you position yourself when out of the saddle. You may find you can find a more comfortable position that works better for you.


What are the securing rings on the disc brake pads pin called?

Usually it's called a Retaining-Ring, poodle-ring or a split-ring. They will look something like this.

Special pliers are made for their removal and installation, but I usually just use needle-nose pliers.

I'm not familiar with that particular model of caliper, but I do think replacing the ring is probably important. In a pinch, you can tightly wrap and twist a piece of wire in the groove usually occupied by the ring to hold you until you get the right part.

Your local bike shop may have spares specific to that part. You can also try your local hardware store. In the screws and bolts section the will usually have bins of split retaining rings because regardless of the application, when you remove one the "springiness" tends to make them fling off into the tall grass and get lost (at least whenever I do maintenance).


How can I mitigate the risk of public urination charges on long rides?

Plan your route accordingly.  Make sure there's a couple gas stations or restaurants along the way that you could stop at if the need arises. It's probably a good idea to be somewhat close to civilization not only for urination purposes, but also in case you have some major mechanical problem with your bike, or you fall and get hurt.  This doesn't mean your route has to be urban, but you should be able to plan a route such that you pass by some kind of civilization every 40-60 minutes.  Alas, if you are that far out, you could always go off a side road or into the bush and relieve yourself there.  If you're so far from civilization that you can't make it to a gas station, odds are that there won't be many cops around to prosecute you either.


wedge/saddle rail mounted bags interchange

I have not found a quick connect system that works with different manufacturers, but have found a bag that I can easily swap between bikes without needing to buy two bags.

I use a Topeak Aero Wedge Medium saddle bag and have found on their support website (store.todson.com) that you can buy extra "fixers" to put on each of your bicycles. The medium Aero Wedge saddle bag carries a couple tubes and my compact pump. It has the quick connect and a single velcro strap which goes around the seat post. Very secure.

I have not had any problems with the Wedge saddle bag when mountain biking (I don't go off many jumps but lots of cross country, single track and rough terrain).

After about 4 years, I did have the thin plastic slot thingy (official term I think) on the bag become brittle and crack. I found the replacement on the store.todson.com website and did not need to purchase a new bag, as such I still recommend the Topeak Wedge bags.


What is the braking (stopping) distance for bicycles?

The stopping distance is a factor of:

Reaction Time
Speed and Mass (bike, rider, and load)
Efficiency of Brakes
Braking force applied (on which brakes and how applied)
Road/track surface (including water, ice, gravel, manhole covers etc aspects)
Tyre width, grip, tread etc

You have to notice a need to brake, move your hands to apply braking force. Then physics comes in, a bike of a given mass moving at a given speed has a certain amount of inertia that needs to be overcome and how much you squeeze the brakes.

So it's going to vary massively by bike/rider/situation.

The same is true of cars. Top Gear (UK) demonstrated a few seasons back the UK Highway Code approved braking distance at 60mph for a car, then showed how a reasonable car could go from 100mph to a full stop far, far, far short of that distance.

It's trained as a rule to car drivers because of the significant damage that can be caused with a big heavy lump of metal moving fast, based on very old figures.

I doubt any country enforces it on cyclists. And road cyclists in cycling groups routinely ride on each other's wheels to get the benefit of drag etc. There training and skill will come in.

Generally, the practical rule trained out in the UK for motorists (and I've been (un)fortunate enough to be required to attend a driver skills course following an incident plus opted to attend some advanced motorcycle training) is the 2 second rule.

Keep a gap of 2 seconds between you and the vehicle in front. That allows you to stop in a controlled fashion. if someone is sat close behind you, expand your stopping zone to buffer their lack of stopping zone. Increase to 4s in the wet and 20s in icy conditions.

On top of that, when it comes to bends, always make sure that you can stop in the space that is visible, so you naturally have to slow down as the road bends.

That said, keeping a 2s gap in a cycle commute is going to have the car behind you putting you at risk!


Will These Bike Racks Fit a 2002 Citroen Berlingo?

Those style of racks are pretty versitile, I would be surprised if they do not fit.

The only problem may be that as you Citroen has a near verticle rear, the bikes may sit further out from the rear than needed, depending on rack design and adjustments. This puts weight further behind the rear wheels affecting handling. I used a Rhode version of these regularly, but when I need to carry 3 or more bikes I use my old 4x4 (Isuzu Bighorn, Opel/Vauxhall Monterey/ GMC Trooper depending where in the world you live) and a towbar mounted rack. Even that car is affected by the weight of 3 bikes hanging off the rear end.

I would hesitate to put too much weight on such a rack, and I would invest in a reputable brand if the bikes are worth a lot, but I have seen racks like these loaded with 4 mountain bikes. Think about what happens if the rack fails - I had a mate who managed a large bike shop, he often had customers buying new bikes after they fell off racks. One customer purchased 4 new bikes after the rack fell off at 100km/h with a logging truck following him.

If you do go ahead with one of these be aware of the common failure modes-  the straps on some models often loosen over hours of driving - so long trips pay speacial attention. Also the ones with the rubber clips that hold the bike, do not trust the rubber. Many internet reviews discuss straps breaking and bikes falling on the road. I always use an independent tie down (bungies are fast and effective), maybe I am paranoid. Also many people discuss problems at speeds like 70MPH - think of the wind pressure of a bike movign sideways at 70mph, even on the back of a car its significant (My car uses 2litre/100km more petrol carrying bikes, all of that is drag caused by the bike....).


How long should a road tyre hold its pressure?

Do yourself a huge favor, inflate them daily.

As they are high pressure and low volume they tend to lose air quicker than that of a tube that is low pressure and high volume (MTB).

With daily inflation checks you will vastly reduce the instances of pinch flats, which IMO are typically the result of too low pressure. Butyl tubes, the typical tube, retain their pressure better than their Latex counterpart but still ... check regularly.

This touches on why your tyres leak down (solubility etc):
Is there a difference in having tires filled with CO₂ vs air?


Highly unlikely this is the gearing for you. Standard chainrings on most drop bar road bikes are 50/34 ‘compact’. 52/36 would be considered a higher gearing choice these days.

It’s likely you will need a lower gearing, especially if you live in a hilly area, so consider a 48/32 ‘sub compact’ on a road bike. You may also want to consider bike that can take a wider range cassette. 11-36 cassettes are available on road groupsets.

You may even want to consider a flat-bar hybrid with even lower gearing and more upright riding positions. Find a good local bike shop for advice and to try out some bikes.


Is SRAM road 11-speed 11-42 cassette compatible with Shimano MTB 11 speed?

Yes.

Same number of speeds, same range, same Hyperglide II freehub body compatibility.


Can 700x28c wheels and tires fit in my MTB frame?

An old MTB will have used 26" wheels (559mm rims), you want to put 700c (662mm) rims on it with smaller tires.
We can work out wheel approximate diameters. Assuming tire height above the rim is about the same as its nominal width and the MTB frame will take a 50mm tire.
559/2 + 50 = 329mm
622/2 + 28 = 339mm (+10mm)
The 700c tire might fit but bear in mind you are also raising your bottom bracket 10mm, which will raise your position on the bike and affect handling to some extent. The larger diameter wheel will also effectively increase the gear ratios.
Note that a 27.5" / 650b (584mm rim) with a 32mm tire comes out to the same diameter as the 559 with a 50mm tire.
584/2 + 32 = 320mm
Finding 27.5" wheels with rims narrow enough to take a 32mm tire make be tricky though.


If the screw is just spinning in place, then the thread that it engages in inside the pedal body is worn-out (metal screw and plastic thread aren't a great combo). This means that the screw is no longer apllying pressure to hold the cap into the pedal. Using something small and sharp, you should be able to lever it off to get access to the grease port.


Changing wheel size when adding ebike kit to tricycle

This answer addresses "stability and cornering"

If you do motorise your trike with a hub motor, it will gain 2-5 kilograms in the middle of the wheel.  This is "unsprung weight"  Depending on the battery number, size and chemistry you will also add 0.5-10 kilograms of storage somewhere on the frame.

So your bike will get heavier by ~3-15 kilos.  This is balanced out by the assistance provided by the motor as long as you have power, for regular straight-ahead riding.

A hub motor in a regular bike's front wheel aggravates any conditions.  If you ride in the wet or on damp leaves, its more likely to slide out under you.   I've never ridden a rear-hub motor, but I imagine its similar, and powering through any corners is a bad idea.

The motor is also unsprung weight, in vehicle terms that's the weight that is always pressing on the road with no suspension.  Increased weight makes jumps much harder, and increases the impact of anything like potholes and road debris.

A test you can do is to get some weights that are about as heavy as the kit you want to fit, and got for a ride with these weights on your bike.  Bags or plastic bottles of water might be safest.  This will show you about how it will feel if the battery is flat.

Personal story - I had an electrified MTB for a while, and it was capable of 40+ km/h with pedalling.  I had multiple instances of cars seeing me in the distance and pulling out without anticipating my speed.

Now I have a road bike and can get to similar speeds without the boost, and because I look faster then cars have been less likely to pull out.

I also found it was too easy to take corners at speed.  Several times I turned 90 degrees and found myself halfway across the car lane, because I was riding to preserve my momentum.  Once I was clear on the wrong side of the road, and fortunately only good luck meant no cars were oncoming.

Summary - ebikes are a gateway drug into riding your bike more.  They're a sop to the conscience for those who want to but can't quite.... as such they do have a place in cycling.

Changing the wheel size is well covered in other questions, like:

Kid's bike - Can I put 20" wheel on a frame that was meant for 18" wheels?
Can I change my 28" wheels for 24"?
Can I run a 700c/28"/29er wheel & tire on a 650B full-suspension mountain bike frame?
Can I swap a 29er fork inplace of a 27.5 if I maintain close to the same axle to crown length?

Short summery is "maybe" if it fits without rubbing, but brakes may be an issue.  Geometry of the bike is also changed in various ways.  I'd expect your forks to be too short for a larger wheel, so you're up for replacing them too, if the trike has forks.


any gps improvement on smartphones with barometer?

Barometric altitude is far more accurate than GPS over several hours IF you have it corrected for the air pressure. Air pressure does not vary quickly.
So if you calibrate a barometer to a known altitude (using a marker, sign, map, or very good GPS fix) it is much better than GPS for measuring an altitude profile


How to select an inexpensive road bike for a heavier rider?

I know that you can buy lots of things online and that prices are competitive online, however, you do need to know exactly what you are buying, and, given that you have posted this question here, you might not be there yet...

Please visit your local bike shop, explain to the sales staff what you are looking for, what distance you are having to put in, whether that is going to be all on roads or on trails, whether you are going to be a fair weather cyclist and what you are going to need to carry. Also mention what sort of money you were looking to spend.

Then let the shop show you 2-3 bikes that meet your criteria. See how the bike feels and, if they will let you, go on a short test ride. Ask about the brands pulled out the rack and why the shop sells them. Also, ask about how much the accessories will cost. You might need lights, you might need the tyres changed for the road and you might want a lock. Hi-viz clothing, a track pump and maybe a helmet also comes into the deal, you will be able to better negotiate a price if you include the accessories - a lot of bikes have a price that the shop (online or otherwise) has to sell at or else they lose the dealership rights, they cannot do a deal on that but they might be able to do a deal on the accessories.

Customisations can work out better of buying from the shop as swapped out tyres can be put back into stock. The same with a seat and pedals (if you go clipless).

Remember that your local bike shop have to compete with the online box shifters, they may not be able to do so on absolute price but they certainly can with service. They are easier to get to for a warranty return and they may well put a free service into the price.

Shops also have cosmetically 'shop soiled' bikes that work absolutely fine but have incurred a scratch during their time in the showroom. You can negotiate a price on these, particularly if they are a 'last year's model'.

Size is really important. Given that you are 6 foot+ you will be needing to look at the 'Large' size or maybe the 'X-Large' size. You can only determine which is best for you for a given brand if you go to the shop. Remember they might not have your size in your preferred model on the showroom floor, they may have one in the warehouse or be able to get one in for you in a matter of days. So, just because your preferred model is not there in your size, don't be put off - try the next model up if it is in your size and then try to order the model/size you do want.

As for your weight, that should not be a problem. However, you will need to keep those tyres inflated to the value shown on the sidewalls if the wheels are to survive. The best way to keep tyre pressures good is with a track pump, these come with a gauge and only take a minute or two one a fortnight/month.

After visiting the local bike shop and finding something you want, you can go online and get a better price. This mail order bike will come in a box and you will need tools and a spare weekend to get it right. If you order from the shop then they will do all that for you, usually to a higher standard than you can do yourself. Plus you will be saving postage. If the local bike shop accessories (e.g. lights) are bought with the bike then expect them to be fitted too.

Hope that helps!


You probably need to check that the shifter is working properly, then set up the derailleur. The problem might be that the cable head is not quite seated in the shifter.

Disconnect the cable from the derailleur. Find a place to grab the cable where it is exposed - the downtube is usually a good spot. Tension the cable manually and work the shifter, you should feel it moving the cable for all gear shifts. If it's hard to feel the cable moving, stick a 'flag' of tape on it and a marker of tape on the frame so you can see the relative movement.

Once you are convinced the cable is being moved by the shifter properly, check the cable/housing run. Everything needs to be firmly seated in place.

Something else to check at this point is that the derailleur limit screws are adjusted properly and that the derailleur can make it onto all sprockets. Manually push the derailleur while pedaling the crank by hand (be careful not to catch your fingers though). If the derailleur will not go onto all sprockets adjust the limit screws - the Park Tool process should tell you how to do that.

When you re-attach the cable to the derailleur:

Make sure the shifter is in the highest gear (assuming 'high normal' derailleur) or has let out the maximum amount of cable
Barrel adjusters are screwed all the way (or at least 90%) in
Pull the cable tight to get rid of any slack

You should find the shifter moves the cable nearly immediately as you select the second higher gear. You can then go through the Park Tool derailleur setup process.


Does anyone sell a direct-drive recumbent with no handlebars?

To the best of my knowledge there are no suitable direct-drive hubs available commercially, which means that there are no bikes sold that use them. Schlumpf make a unicycle direct drive hub that offers 1:1 and 1:1.55 gears, but for a recumbent bike those ratios would be ridiculously low. Also, it's obviously fixed gear so without a freewheel it would be even less useful on a bike.

You may be able to convert a standard hub gear to direct drive, using a larger axle and feeding the drive through the centre. Hubs are designed to have drive from one side, and pedalling torque is quote large so this would probably involve a major redesign of the hub (I suspect this is why so few people have built them). Another problem is that hub gears are designed to have 2:1 or more gearing up from the chain drive before the hub. So once you got it working, you'd have lower gears than you expect. Using short cranks is a partial solution to that at best, but it's the only thing I can think of that might help. Greenspeed suggest that 100mm cranks are quite usable with only a slight loss of power (but higher rpm = lower gearing needed)

Your second question, about having no handlebars, is much easier to do. Most front wheel drive, moving bottom bracket bikes can be ridden hands-off, and it's relatively easy to learn to ride without the handlebars at all. The problem is that most countries require bikes to have handlebars (it's an offence to ride without holding them).

One problem I see with the design you link to is that it's partially rear wheel steered. That will affect stability (making the design somewhat harder, but if you're buying one they've already solved that problem). But it will also affect turning. To turn away from something, the rear wheel must move towards it. All rear wheel steer vehicles suffer from this problem. One partial solution is to use a tadpole tricycle configuration, so that the rear wheel is between the front wheels and thus can move sideways as far as one front wheel when turning away from a kerb or other barrier. For a bicycle, the solution is to stop and lift the bike away from the barrier. The problem is that if you run up next to a barrier at speed it may be difficult to stop without hitting the barrier. That's annoying if it's a kerb and you end up sliding along the footpath, but can be dangerous if it's a wall or hedge.

With unusual bikes that someone is selling, I find it's helpful to ask how much someone other than the inventor has ridden one. If they've sold a few and someone has ridden a couple of thousand kilometres on one, then great, it's probably usable. But if it's a great project by one person and you're going to be the first real customer... be very careful.


Answer: No - you can't just move the brake levers up the curve of the handlebar drops.   If you did this, the bar tape would be bunched up above the hoods and skinnied-out below the hoods.

Tools: You'll need a 5mm hex driver (maybe 4mm or 6mm, maybe a philips if its old, or flathead if its ancient)  Some tape to finish the bartape wrap, and sharp scissors to cut the tape.

Method: Unwind the bar tape carefully, reposition the brakes, then do up the bar tape again.  You'll probably put one, maybe two turns of bar tape below the brake hoods that were above the hoods when you started.

The brake cables should move okay - you might need to remove and refix some temporary tape.


Generally speaking, that style of bearing ("sealed cartridge bearing") is "permanently lubricated".  You do not lubricate them and you replace the entire assembly if anything goes wrong with them.

A few people have claimed success by gently prying back the flexible gasket and injecting grease with a syringe, but these claims are subject to legitimate skepticism.

Note that the inside diameter and the outside diameter are not supposed to move relative to the external parts that hold them.  If they are slipping it indicates that the "holders" are not tight enough or the bearing is failing and needs to be replaced.


Which is ideal road-bike size for a person with height 5'9.5"?

Ten thousand expert opinions can't match a single objective test. I'm about your same height and inseam. I have 52cm, 54cm, 56cm, and even a 51. They all fit, and work for me. One manufacture's 54 will sometimes feel like another manufacturer's 56cm. Fit isn't just about frame size. Stem, saddle position, spacer count, all play into it. Ya gotta test ride a couple of different makes and sizes. If you're like me, you're gonna want to write your findings down on paper to review once the "wow, that was cool" factor wears off a bit.


You do have some margin for error with spoke lengths, so do round off fractional lengths.

For spoke type, a double-butted 14/15/14 spoke would probably be ideal, short of that a straight-gauge 14-gauge spoke (straight-gauge is cheaper; double butted is preferable because it puts extra material where you need it, so the spoke is more evenly stressed over its length). If you feel you really need something beefy, go for 13/14/13, although that may be harder to find. Get stainless spokes and brass nipples (aluminum nipples are more prone to corrode).

DT and Sapim are the big names in spokes. The only spokes I've seen that I would specifically dis-recommend had S-hooks at the end instead of a J-bend (and those were hooked because they were aero spokes, so probably not an issue for you).


Why do we sit on saddles that rest on seatposts? (and not on seats that rest on saddleposts)

Like most things in English language, established convention. According to Google N-grams, "saddle post" along with "seat post" was used until 1950s, after which "seat post" became dominant.


For the most part you can just disconnect the lever end, taking off the olive but leaving the barb, shake off any loose drops and pull it through. The system is closed on the other end so it won't come spilling out.

Two other ways if you want or need to do something unusual: disconnect the hose from the lever, attach a bottle to the hose to connect the fluid, position the bike so gravity will do the work for you, open the bleed port on the caliper, and let it sit for a while as all the fluid drips out. Shake it to get the last droplets out before pulling through. You could also blow air through the hose first (not with your mouth) if you wanted to be faster or cleaner perhaps.

Alternatively, cut off the hose above the barb and find some kind of round thing to shove up there to plug it, then pull it through.


How do I mount this Topeak rack onto this road bike with disc brakes?

You have the seat stay mounts on the frame (those are the two thin tubes that go from the rear wheel drop outs to the top of the seat tube). What you need is mounts on the rear wheel drop outs. Typically, they are part of the dropout and/or frame. In your case, you have none.

That being said, the P-Clips and Tubus Clamps will not be useful.

The Tubus Adapter Set for Quick Release Axle Mounting should solve your problem. It is built for a Tubus rack which has two mounting holes at the bottom that are meant to be used simultaneously, thus the two slots. You can choose which one is appropriate once you loosely install the rack and check how level the top is. Installation instructions and a drawing to go with it can be found here.

I should say I have not done this actual installation myself, but I see no obvious reason why this would affect anything else. There are comments from people that have used this with discs and there's a spacer to keep the mounting plate away from the frame, so you should be good.

The only concern I have is there seems to be nothing to prohibit the mounting plate from rotating fore or aft. You may want to invest in a couple lock washers and a proportionally longer quick release.


What are the differences between men's and women's bike frames?

Way back when safety bikes were becoming popular, women wore skirts. Skirt lengths were to the ankle. The dropped top bar made getting on possible while maintaining respectability. Women were considered too fragile to risk hitting the top tube, hence the slanted bar. The trend continued even long after women stopped riding in long skirts.

Modern WSD (women specific design) geometry differs from conventional bike geometry. The difference goes beyond just size. Whether it is needed depends on who you ask. While some women may be smaller than the average male, many are as tall; height is not the only issue. Many women have a different leg to torso ratio than the male average and the frames are built to fit that difference. This is not to say that a women needs a female specific frame or that a male wouldn't fit on a WSD frame. It all depends on the individual physical traits of the rider.


Given that all other things, e.g. type/diameter of the axle, are the same, the difference of two teeth on the middle chainring do not present a problem.


Are there any adjustments for hydraulic brakes?

There is no adjustment for modulation on the Apex hydro brakes, but make sure the lever reach hasn't been set too far in, which could screw things up. Also soft feel, lack of stopping power, and ability to pull the lever easily to the bar can always just mean they need to be bled.


Coaster brake suddenly not working (Nexus 3-speed hub)

It may be a broken brake shoe, or possibly a broken clutch spring. This usually happens when the axle nuts are not tightened to the correct torque (30Nm), or the wheel is put back on without the non-turn washer.

Take it into a shop that has a Shimano dealer account. If you want to fix it yourself, they can order you the entire internal assembly (it comes in one pre-assembled piece, part #1 on this diagram). Make sure you emasure the length of the old axle, and order the same sized new one. With some minimal work (this link), you can remove the old assembly, pop in the new one, and get your girlfriend back to riding.

NOTE: The above video shows how to remove the coaster brake shoes. You are not trying to do that! Simply replace the entire unit.

If you'd rather not do the work yourself, a shop shouldn't charge too much for it, and the work will be warrantied as well. They can also check the hub for any other damage.


New stem, bars & shifters on old Bridgestone 700

you should be able to get a variety of 22.2mm quill stems. For instance SJS have a fair selection (picked because they came up first in a search for 22.2mm quill stem, I have no connection with them). 22.2 is a standard size and still common.
If it has indexed shifters you should have no problems, but Shimano 600 may not be indexed, and might be 6 speed. In which case you can look for thumbshifters with a friction mode or change the drivetrain. The cost of buying new 7 speed drivetrain parts is enough that I wouldn't suggest it - you'll spend a fair chunk of the cost a new cheap bike doing it. If there's a bike recycling group or tip shop in your area you should be able to avoid spending most of the money - old bikes with 7 speed indexed gears are pretty common.


If you have a one month old bike bought new you should be able to take it to the shop you bought it from for a free drivetrain and brake tune up, and to address problems like these that crop up in the first few weeks of ownership.

The click is very loud and occurring at low speed. It does not sound like the indexing being off a little. It sounds like the chain in catching on something  but I cannot see it moving on the smallest sprocket so it's not trying to jump to the next largest sprocket.

I'd look to see if the chain in catching on something around the derailleur cage.

Check that the wheel is seated in the dropouts properly. If the wheel shifted significantly the sprockets will not be parallel to the derailleur cage. Another possibility is that the derailleur hanger has been bent which will also misalign the sprockets and derailleur cage.


Can I use an 1/8" chain on an old 8speed I'm converting to single speed?

Yes, you can use an 1/8" chain instead of 3/32", is the other way around you can't go.
However, it may have problems going through your deraileur, but we can't say for sure. For normal single speed or fixies that's not a concern.
I would use a normal 8 speed chain anyway, it'll probably be cheaper. Only get an 1/8" chain if you get track chainrings, or you want the colored chains, which I've only seen in 1/8" size.


Replacing a tire isn't that hard, but it will take a few times for it to seem like second-nature. If you have a road bike with skinny high-pressure tires, you can expect that the tires will be harder to remove and replace.

This is how I do it on my touring bike, offroad bikes, cruiser, and folding bikes. You'll need a pump to match the valves used on your bike (presta or schrader), a spare tube, and a place to work. Tire levers would be quite helpful.

Deflate the tire (if it isn't already completely flat).
Remove the wheel from the bike. This will probably require that you disconnect the brakes (if you have rim brakes, as the vast majority of bikes do). If your bike doesn't have a quick-release hub, you'll need a wrench for this.
Remove the tire from the wheel, if possible with the tube still inside. You may need a tire lever for this; it's a small plastic dookickey you can get in any bike store for a few bucks, usually in sets of three. You use it to pry the tube over the rim by working the edge of a tire lever under the edge of the tire and prying it over the edge of the rim, then sliding the edge of the tire around the edge of the rim; the tube should pop off when you've completed a circle. Two or three levers makes working with high-pressure tires easier. Once one edge of the tire is off, pull the whole tire and tube off the wheel in the direction of the side you were working with the tire lever, starting on the side of the tire opposite the valve. (Using a flathead screwdriver for this is not advised, as this can scratch the edge of the rim, potentially damaging the wheel. With some lower-pressure tires (such as mountain bikes or children's bikes) you may be able to remove the tire from the rim with no tools at all.)
Search for the object that made the puncture, and remove it. This may be a thorn, or a nail, or a piece of glass, but whatever it is will likely be sharp, so be careful! You may have to feel around with your fingertips, or submerge the tube in water and look for rising bubbles, or even turn the tire inside out. If you replace the tube without finding the object that caused the flat you may well get another flat. (If no cause for the flat is presenting itself, you may be getting a flat from the rim itself or a spoke poking the tube.)
Get your spare tube and put a little air in it, just enough to place it on the rim.  Put it on the tube, with the valve poking through the valve hole in the rim.
Replace the tire over the tube, pinching the tire to be sure that it's not pinching the tube as you inflate the tube inside the tire. Be careful that the tire is inflating evenly; the first few times you do this, you may want to inflate it a little at a time and check as you go.
Once the tire is inflated, re-install it on the bike, and please make sure to tighten your quick-release and hook your brakes back up.
Get back on your bike and enjoy your (for now) shiny new tire!

Watching a video or seeing pictures probably makes this all seem simpler; the other answers provided links to these resources. Bonus: More information that you'll ever need to know about tires and how to replace them: What Every Cyclist Should Know About Flat Tires


Is it possible to tighten/replace my wobbly spider?

The FC-M480, as originally identified in the question, is a 9-speed, Deore level crank. This is a link to Shimano's spare parts diagram. Here is a link to the M460 crankset's parts diagram. Neither indicates that the spider is available as a spare part. For Shimano cranks of this era in general, I don't believe the spider can be practically be separated from the crankarm. The road cranks generally had the spider forged with the arms. As shown below, the M480 and 460 do appear to have separate spiders, but the spare parts diagram indicates that the spider isn't available as a spare part, nor is there an obvious lockring. Hence, the spider is likely bonded (i.e. industrial strength glue) to the crankarm. The image is of an M480 crankarm-spider interface that I stole from an eBay listing.

Note the supplemental discussion in comments: the OP checked that their chainring bolts were tight and that the crankarm was tight on the bottom bracket. When the OP wiggled one chainring, all three rings moved together. Unfortunately, that points to the spider moving. As it isn't secured by a lockring, this likely means the bond is failing. While that is presumably very strong glue and this should be a rare event, this is unfortunately not out of the question. There have been a few reported failures of Shimano's higher-end road crankarms, which are forged in two pieces and then bonded together. In these events, the bond fails, possibly exacerbated by salty air.
It might be impractical to re-bond the spider to the arm. While I've never done anything like this myself, I would expect that the existing adhesive would need to be dissolved. That might harm the anodizing. Then, after cleaning off any remnants of the adhesive, the OP would need to select a proper adhesive, and re-bond the arm and spider. I'm not sure if the application procedures for appropriate adhesives are achievable by typical home mechanics. In any case, it could be possible if you knew what you were doing, but I expect that it would be much more cost effective to buy a new crankset.

As a side note, Shimano's 12-speed MTB cranks appear to all be direct mount. Here, the spider is integrated with the chainring, not the crank arm. You fix the chainring to the arm with a splined interface. If one had that type of crank and bent the spider or the chainring, you'd just replace the chainring as one unit. That requires a lockring tool, e.g. the Park LRT-4, plus a wrench to hold that tool. However, the Tourney cranks in question are definitely not direct mount. If they were, the parts diagram would show a lockring rather than mounting bolts, and they would show the spider arms integrated with the chainrings.
As the OP indicated, the spider could have been bent rather than the bond coming loose. If the spider were bent, however, it would not explain the symptom of the chainrings wobbling together when moved by hand. Also, it would take a lot of force to bend the spider. After all, the spider's arms are short and are relatively thick aluminum, and they have a bunch of chainrings bolted to them that would collapse first under the impact.


To add to Andy's comment, there are so many factors at play that you won't know if a deeper drop gives you any aero gain at all without something like a wind tunnel.

Changing the position may or may not give you a second or two over 100k, but you also have to consider your power output may or may not be less in the "new" position, which could negate any aero gains. If say that's worth considering, to get to your question.

Moreover, I think comfort is a bigger consideration. If you're not comfortable in the new deep drop position your power output will almost certainly be less over any significant distance.

Try it before the race over a shorter distance on a route you ride regularly and compare. Or, get on the rollers with your new bars and have someone watch/record you. Is your back straight? If so that's good. Are your hips/pelvis rocking more? If so that's bad.

To summarize, you're not going to know if it's more aero outright but you can weigh and compare the symptoms/boons of a new position and make an informed decision if it will make you faster.


Buy Time-Trial bIke or convert road bike

The geometry is the major problem with converting a road bike into a TT/Tri bike, road bikes have you sitting much farther back relative to the contact points on the handlebars.

You may be able to offset this with a different seatpost that puts you farther forward (assuming saddle is adjusted all the way towards the front).

Other changes may include a shorter stem, different saddle.

You may be able to make your road bike work, just don't expect to be comfortable mid ride switching from the aerobars to the hoods/drops. You have to pick one and stick with it.


Your valve has slipped partially inside the hole in the rim where it exits. Normally it's on average about 1-1/2" outside the hole. You'll need to inspect the valve body to see if it's cut. You can't put a pump on it because the main body of the valve is stuck. First fix the valve body position, then inspect... Here's how to fix:

Deflate the tire about 90%.
Grip the tire where it meets the rim and pinch it together with your fingers. Do this for the circumference of the wheel. You want the bead of the tire the part closest to the rim to release completely.
Now grab the tire in one hand and the spokes in a another, hands about a foot apart.
Gently pull your hands together in opposite directions. The goal here is to get the flat tire to slide on the rim, straightening the valve. You don't need much about 1/2" to and 1".
Use your fingers to jiggle the valve back and forth to get it to pull fully out from the rim hole. Optionally use pliers but take care not to crush the valve cap threads. If it helps put a valve cap on to pull up and out.
Here's your answer --> With the valve position fixed you can now visually inspect the valve. If you see cuts on the side of the valve body you might have a valve flat that air will leak from.
Fill the tire back up taking care to keep the tire bead on and no inner tube bulging out from the rim.
If you saw cuts in step 6, jiggle the valve and make sure you don't hear air escaping. If you do the valve is damaged, replace inner tube. Optional: A bit of slightly soapy water works here too. Cover the valve body with soapy water. If you see bubbles leaking, that's bad, replace tube.

It's always good maintenance to keep your tires pumped up to pressure. Pay more attention to this if the bike has been sitting a bit. If you ride with low pressure the tire can slip on the rim giving the condition your valve is in. Good luck! :D


The one piece seat-stay/chain-stay construction looks like a Hutch* from the early 80's however, having both the left & right side stays made from one bent tube doesn't match up exactly with anything I have looked at while browsing the BMX Museum. It might be something from the late 70s (they only have from 1980 on pictured there). Or it might be a knock-off cheap copy of the Hutch design. That might be a good place to continue your search.

Based on the eBay prices of some of these bikes, I'd say you've likely got yourself a valuable project on your hands!

*I picked Hutch based on one that was similar looking on eBay that came up in a search for "bicycle gt 4130 cro mo team".


Replacing one derailleur with another type

The derailleur you linked is compatible.

In general, Shimano shifters for 9 speeds or less for off-road series and 10 speed or less for road series are interchangeable if the mounting scheme fits. 7-speed cassette is narrower than 8-speed, but the derailleur probably has enough room for adjustment to fit the wider cassette (edit: actually, it was 7-8 so it definitely should work).

The derailleurs for more speeds require a corresponding shifter to work correctly. Derailleurs from other brands are also not compatible without tricks with adapters, with the exception of some old SRAM units specifically marketed as Shimano compatible.


How to prepare a frame for a new paintjob

A few tips:

Painters don't know anything about bikes. If the paint shop is not specifically a bicycle paint shop, they may still offer to strip your bike of components for you. Don't let this happen! Most painters are unfamiliar with the intricacies of bicycle mechanics, and may improperly remove or damage some components, or not know or have the tools to remove others. For example, I've seen the pressed-in cups of the headset get painted over on more than one occasion.
Remove all the components. If you're not comfortable doing this yourself, a bike shop will be able to correctly do it for you.
Make sure the painters are aware of what needs to be masked off. Areas with exposed threads such as the bottom bracket, water bottle cages, braze-ons for racks, fenders, or brakes should not be painted over! If the paint goes on thick, you might not be able to use these threads without re-tapping them.
Don't worry about frame prep. This is what the painters do know how to do. They'll know the right methods for removing the old paint, such as sandblasting.
If your frame is being sandblasted, worry a little about frame preparation. Figure out what quality tubing your bicycle frame is made of. If it's heavy and thick, don't worry about it. However, if it's a nice, lightweight tubing such as most Reynolds brands, the tubing is in fact very thin at some points, and should not be roughly sandblasted! If the 'sand' is not fine enough, it may dent or severely weaken your frame.


Can I run a wheel with a 130mm hub on a mountain bike with 135mm spacing?

I've respaced a steel road frame from 130mm to 120mm for a track hub. It's super easy, although Mr. Brown recommends not doing this for a change as small as 5mm.

I'd try a 135mm mountain disk hub with a 700c cross rim, this gives you the most correct breaking surface on both setups.

The advantage here is that when you come to put the 130mm road wheel in your cross bike, it still fits. Although your cross bike MUST be steel and not aluminium of carbon.

One last thought, this whole scheme is going to be a bit of a bodge however it's done.

I'd be more tempted to have a pair of shared road wheels, where the stresses are much lower and a dedicated pair of off road for each bike. A 120mm/700c cross set, a 135mm/29" MTB set and a 135mm/700c shared set with slicks.


Can anyone tell me what make or brand this frame is?

Sorry  serial numbers are only helpful if you already know the manufacturer AND they used some kind of system, AND kept records AND EITHER those records are available for searching, OR someone has figured+published the encoding system.

As it stands, I see a BMX frame with rear brake mounts for either U brakes or possibly V brakes if its more recent.  This shows it had rear brakes when built.

The trackends show its a single speed, so no gears.

The large bottom bracket housing shows it was probably a 1-piece crank, not a 3 piece crank like a nicer bike.

Upshot - it could be any brand, but the odds are its a low-grade big-box-store kids bike.   I do hope you have more of the bits than just the frame, else building it up will be expensive.


It depends on your transmission. Some internal gear hubs, for example, are perfectly happy being shifted at a standstill.

For a derailleur based system, you should shift while in motion while pedaling lightly. It isn't ideal to shift under load, and shifts will be sloppier under load typically.

The question of when to shift while riding is a matter of personal preference -- ideally, you want to maintain your cadence or power output, but due to obstacles, you might downshift and get into an appropriate pedal position for continuing riding. It's like shifting in a car -- there are certainly wrong ways, but there isn't necessarily a right way.

For example, if I need to round a corner and slow down before, I might shift down before the corner, get the pedals in a position I can round the corner without striking the pedals on the ground, go around and start pedaling again. But I could also get the pedals in position, slow down, come out the other side and downshift and continue going. Neither of these is wrong, but the first one is likely easier.

It's also a good habit for coming to a stop and starting -- starting in a high gear is not so nice, and shifting down can be a bit jarring unless you build up a bit of speed in the high gear.


Derailleur problems - rear mech slipping forward

I have started to notice a problem in my rear mech - the link arm screw that holds the mech to the dropout seems to slip and cause the whole derailleur to swing forward until the cogs are sandwiching the chain against the sprocket. Now I'm no doctor, but I can easily say that sort of cramping is bad.

Strange that this would be where things are coming loose. My recommendation is to remove the rear wheel and chain and make sure nothing else is coming loose either. If it's just the connection to the hanger, check the threads on both the derailleur and the hanger as one or the other may have damage or contaminants. Clean and lube/locktite the bolt and re-install the derailleur. If you continue to have problems, I'd have a mechanic check it out.

  Secondly, how tight must this screw be? Wrenching it as hard as I sensibly and safely can with a park tool only holds for a while, and then the problem repeats. Also, how would you measure tightness? (I feel like there is an obvious answer there that I should know already...)

Park Tool recommends 8-10 Nm or 70-86 lb-in. You can easily measure this with a torque wrench, you can get a cheap one from a hardware store or go for a more expensive one if you want something that lasts.

  Finally, given the problem occurs on the trail, and specifically I think on landings and rough patches, is there something in my riding style that could help prevent damage. Advice is welcome, but I'm not an absolute beginner.

Just trying to stay smooth is about the only advice you need. And don't land to flat! That puts a lot of stress on everything.


Lightweight foldable shoes for road cycling

I use some of these if I'm touring and want to travel light, I put them in my bag but I reckon they could slip in to a jersey pocket, I'll try after work today.

I've used cleat covers before and, though they protect the cleat, didn't feel they were a proper solution - you still end up walking weirdly because the only contact point is the cleat.


Bike pedals not moving for upright position

Since you don't mention that you don't have a fixie where this wouldn't be possible anyway, if your bike's rear brake has a back-pedalling aka coaster brake, turning the crank backwards is indeed not possible. It is system-inherent.


You can calculate your speed vs cadence using this online calculator. You want your cadence to be roughly 80 rpm (60 being the lower bound).

With a 42t chainring and 14t cog in the back (not uncommon for a 26" mtb -- this is big ring in front, small in back), you should be doing around 31 kph at 80 RPM, so chances are you're either spinning too fast in a too low gear or spinning too slow in a too high gear.


Why would spokes break at the flange early?

I've broken a spoke on a well-built wheel simply from hitting a bump in the road a little too hard. And on a generic wheel, I've seen that when one spoke breaks, the spokes at 90° intervals from it start breaking, even after I replace the first broken spoke. My guess is that this reflects a pattern of underlying stresses. So neither of your spoke breaks surprise me that much.

Since this is a Rohloff hub, you shouldn't have super-high tension on just the drive side due to dishing, so we can rule out that frequent cause of spoke breakage.

It might be fatigue. Jobst Brandt regarded fatigue failures as a consequence of failing to stress-relieve the spokes when the wheel was built.


Recommendations on how to make grips more comfortable?

I really think this is a fit issue (e.g., changing the bar height and/or reach, how you hold the bar) rather than finding softer grips or padded gloves.  Numbness should be taken seriously (as it can lead to permanent damage if left unattended). Padding tends to help deal with issues associated with high frequency vibrations, rather than too much pressure that can result from poor fit. With soft padding if there is too much pressure this just tends to force the padding further into soft tissues, which can exacerbate the numbness.

Ideally, with the proper fit your hands should only lightly touch the handle bars, which should make numbness rare. Excess pressure suggests compensation from incorrect fit.


What are the advantages of bikepacking bags?

They usually keep the bike narrow, suitable for trail riding where branches might snag panniers.

They use soft attachments (usually), so extreme vibration doesn't make undue noise or wear things out.  There are people with damaged racks simply from plastic pannier clips bumping along on them for months on end.

Cheap "bikepacking" (with scare quotes) bags are cheaper than cheap panniers plus cheap racks.

Bikepacking bags also help packrats reduce their load, simply by being more constrained than large panniers.

They're also suitable for rental bikes, when you're away from home.


What should I look for in a good pair of cycling shorts?

What type of shorts?

First you need to work out what sort of cycle shorts you are looking for:

Regular cycling shorts - these are your classic lycra bike shorts, no bibs, no extra fancy bits.

Generally quite comfortable
They do have a tendency to "roll up" under your gut a bit, particularly for those of us that carry a bit more weight than we should.
Obviously a lot easier to relieve yourself with these - probably an important consideration on longer rides

Bib shorts - like regular cycling shorts, but with a "bib and brace" arrangement that go over your shoulders to keep the shorts up.

Even more comfortable than regular cycling shorts as they don't have the tension of the waist elastic around your waist and they tend to stay in place better.
They don't roll up under your belly like regular shorts
They are more awkward to go to the toilet with, requiring you to either remove half your clothes, or stretch them around a bit.

Shy shorts - basically normal looking shorts with a cycling short liner.

Less comfortable on the bike than proper cycling shorts, but still a lot better than non-cycling specific shorts.
More durable, which is often a good thing when mountain biking
If you are not comfortable wearing lycra in public, or are going to be off the bike for a while during the day, they can be less embarrassing to wear.

Undershorts - like regular shorts, but usually made of a lighter mesh fabric to allow them to be worn under other shorts or trousers.

Allow you to have most of the comfort of bike shorts with any of your regular clothing.

What features to look for?

Now, what are the features that you are looking for in good quality bike shorts:

A high quality chamois - these days this means that the chamois should be "3-D" molded and offer a reasonable degree of padding, but not too much.
Good quality material - look for the fabrics that have 4-way stretch rather than 2-way stretch. they will fit your body more closely.
Leg grippers - good leg grippers at the bottom of the shorts will hold the shorts in place without being excessively tight. Often they will have a "tacky" rubber feel.
Number of panels - the more panels, the more the shorts are tailored to fit your body.
Height at the back - not really applicable for bib shorts, but regular cycling shorts should be long in the back so that they don't expose your back when you are bent over in a cycling position. Some cheaper shorts don't do this.
Compression fabric - a more recent trend, but some cycling shorts are being made with a compression fabric that applies more pressure to your muscles to help them perform better.


Chain loses tension on straight drop out

You need to get a tuggnut (also known as a chain tug). Surly has an excellent one that I use. I was getting the exact problem that you were until I got the tuggnut and since then haven't had a problem. They also sell cheaper ones at BMX shops or you can search on eBay for "Chain Tug" and find many cheaper options.

The other bonus is that it makes adjusting the tension really easy. You can dial in just the right amount of tension then take your time getting the wheel straight and the bolts tight.

I would also recommend getting a better spanner so you're not going to ruin the wheel bolts, but even with a ratchet I was still getting slipping. The tuggnut will solve this completely.


I usually ask my LBS when I need spare parts like that. You might have to pay them a buck or two, but a lot of places keep a small stash of parts like that.

If that doesn't work, they might be able to order the part directly from Shimano (or ask your friends).


Can I use a 6mm threaded bolt instead of a bleed valve for hydraulic brakes?

Well you won't be able to bleed your brakes for one thing.  You can buy bleeder screws at auto parts stores.  I've never bought one, but 6 mm sounds like a normal size.  I'd check there.


Higher-end bikes are expected to be used with clipless pedals. However, there are several different standards for these pedals, and all of which have a different type of cleat that fits in them.

Most cyclists tend to stick with one of these standards across all of their bikes, so they don't have to have multiple sets of shoes. Thus higher-end bicycles typically are sold without pedals so that the customer can select the style of pedal that matches their existing shoes.


Help identifying make of steel elevated chain stay mountain bike frame

Roadmaster Techno Trac.
Sears never made bikes, they bought them from other companies like Steyr, AMF-Roadmaster and Murray.

see one here with the original decals still intact (and a broken frame)
https://www.flickr.com/photos/rickpaulos/49958454372/


No, it doesn't seem like much, but that stem won't fit your bars without a shim. Very wise of you to ask. Nitto (and probably others) make shims for just this situation. They cost about $10 US. The old standard for road bikes was 25.4 mm (for the most part), but there seems to be a move towards 26.0 mm.


Adjusting brake rub on a mini-v brake (Giant Propel)

The small screw to the northwest of your red circle in the picture is the spring tension adjuster. Tighten it down to increase the pull on the left side.

You may also want to loosen the screw on the right side if there is a large imbalance in tension between the two arms.

The bolt you tried adjusting simply holds the brake arm on. It doesn't have anything to do with the adjustment of your brake.


Can you change your skewer frame into to thru axle one?

Frame rear dropouts and forks for through-axles are of a substantially different design than those designed for quick-release hubs. Through axles are essentially a large bolt that attaches the wheel to the frame whereas quick releases (and older threaded axles clamp the hub into slots.

Most frames and forks cannot be easily modified, the dropouts are permanently attached. Steel or aluminum frames or forks could be cut and new dropouts welded in, but this of course would be difficult and expensive, especially as through axle dropouts have to be aligned much more precisely than quick release ones. Carbon fiber composite frames I suppose could be cut and new dropouts bonded in, but this would likely be more expensive than modifying a metal frame.

Forks can of course be easily replaced. some manufacturers offer frames have removable rear dropouts that can be swapped for through-axle, quick release other style dropouts.


How often should we add inner tube sealant liquid?

It depends. If you have regular tube tires and the sealant was something like Slime, then in theory you don't have to put more in unless you have a flat. In reality, Slime thickens over time. You can't really add more, so you might expect to change tubes every couple years. Riding your bike regularly will help prevent the Slime from coagulating in one spot and causing an unbalanced tire.

If you have tubeless mtb tires, and used something like Stan's then you should reseal every 2-6 months according to the manufacturer, more often if you have punctures or loss of air.

In either case, you want to keep the total volume of sealant the same over time. Which means you do not want to add more unless some has leaked out or you're able to remove it through other means (this is easy with tubeless tires; it's near impossible with tubes).


How do I know what gear combinations should work without chain rasp on front derailleur?

There are two approaches here:

The standard rule is to avoid cross-chaining. It means that you don't use large with large and small with small. The large sprocket at the rear should not be used with the large ring at the front. In the same manner you should not use the smallest rear sprocket when your chain is on the smallest front ring. In both cases the chain runs quite diagonally or sideways when you look from above. It puts a lot of strain on the drive components and the chain is most likely to rub against the front derailleur plates. With a triple the use of the middle ring is less critical. It may work with any rear sprocket. But still, depending on the position of the chain, rubbing against either FD-plates is possible, so you should avoid the use of the two extreme sprockets.
The previous being quite old school, newer derailleurs and narrow chains are less affected by cross-chaining, if you leave out the higher wear of the drive train. Especially modern indexed front derailleurs don't have just three positions but two for each chainring or even three for the middle one. You can notice these if you carefully actuate the shifting. You will notice that when the derailleur is as far right as possible, a slight touch of the lever will have the FD move inboard ever so slightly without throwing the chain off. This position is meant to be used with the larger rear sprockets. It will only work with carefully adjusted indexing of the derailleur which may be fiddly. Some makes, like SRAM have FDs with a special geometry of the plates that doesn't require trimming where electronic shifters trim the position of the FD according to the position of the rear derailleur

Note: in the days of non-indexed shifting and down-tube levers it was customary to the adjust the position of the left lever slightly when the 'ear-meter' registered noise from the chainrings.


Burping v/s bleeding hydraulic disc brakes: is it safe?

You aren't assured of getting all the air out of the system.  If your bubbles are further down and this doesn't remove them, you may actually introduce more air than you remove when you replace the cap.
You won't effect a fluid change this way.
You won't replace the crush bolts and other pieces swapped at the true bleed that are        potential sources of failure.
If something happens and you bump/spill some fluid, you are SOL for replacing it.
If you have a leak that has introduced air, this may not help any.

Not to say this isn't a decent method to try for a home mechanic as an initial troubleshooting step if you are into it.  It may be done faster, with little to no cost, and may help some issues.  However, you are correct, it does have several shortcomings.


How much is a mass production aluminium road bike frame worth?

There is no specific way to calculate the worth of a frame when taken from a complete bicycle.  The market will tell you how much it wants to pay for such a frame, but the theoretical calculation of "The frame is worth the complete bike price minus the price of all other components'" is wrong.  Firstly it's wrong because it ignores assembly and value-add pricing.  Secondly it's wrong because it ignores the steep discount you get when buying a complete bike.

Imagine asking how much the chassis of a Ford Explorer is worth.  If you try to buy all the other parts separately, the total will be more than double what a complete vehicle would cost.  Bikes are a bit like that.


The Park  BBT-22 should work, but if you don't already have one, you might find the Shimano TL-UN74-S cheaper.


Do Kevlar Belts really offer puncture protection?

Kevlar fibres do resist cutting, and the kevlar belts in my tyres have certainly stopped lots of sharps (mostly glass and flint).

What it won't protect against are pinch flats (which you can avoid anyway by keeping your tyres at the right pressure) and, if it's just a central belt, it may not protect against sidewall cuts either.

There's generally a tradeoff between ride quality and puncture resistance FWIW: my tyres are lighter and faster than Schwalbe Marathon Plus (for example), but also less tough.

If you want anything more than generalities, you'll need to name those tyres and ask about them specifically.


How do you download OSM maps to Garmin Edge?

You can get map files that work on Garmin devices (I haven't tried with Edge) from this site. You can select predefined areas (countries, provinces) of the world you want, or create custom selections of just your area. They generate a map of your desired area and send you an email when its ready so you can download it.


Is there any reason I can't convert a 36/46 to a 36/52 chainring?

My guess is: since 50/34 and 11/32 works well, because it is commonly used, so should 52/36 and 11/32. Same tooth difference (16) between the front chainrings. Same total capacity (read further).

Take a look at this technical document
For Item 11 (inner chainring), it says Chainring 36T-MB for 46-36T/52-36T
For Item 12 (outer chainring), it says Chainring 52T-MB for 52-36T
I think you can conclude from that: 52-36 is supported by Shimano.

Now for the rear derailleur:
Ultegra RD-6800 comes in two cage lengths: short (RD-6800 SS) and long (RD-6800 GS)
Use this post as a guide to choose between the two.
Your total capacity becomes 32 - 11 + 52 - 36 = 37.
That's the maximum for the long cage.

Now about the chain:
This video illustrates perfectly how to determine the correct chain length. It shows that you need to use the inner chain ring and the smallest cog on the cassette (36-11). If you follow this rule, your chain length should be OK. Indeed the rear derailleur will be stretched even further than it already was in the other extreme (52-32).

Also an interesting read: Sheldon Brown's take on derailleurs


How do I remove the freewheel side of a flip flop hub?

You need a freewheel removal tool.

That looks to me like it will take an FR6, but you should measure first if you're planning on buying. Although, this will likely be the only time you ever use it unless you open a bike shop.

Your local bike shop will almost certainly have one of these and be able to whip it off it no time. They might not even charge for such a small job.

Sheldon brown has instructions on the rest the removal. Basically, you just need to put the tool in a vice, place the wheel on it and turn. He recommends using a quick release skewer to secure the tool, but you have solid axles so just be careful.


What should you do if you find a bike that appears to be stolen?

As private citizen you cannot do much more than reporting it to the police.

If it was stolen and the theft reported, the legitimate owner may have it back.

If it was thrown away, there is the chance that the police will arrange the removal.

(Both points strongly depends on the country where you are located. In some places police officers may simply laugh back at you for reporting a suspected stolen bike, but again, if you take it you are breaking the law, too)


Yeah, I managed to do this one one of my bikes once. There was no way I could brute force the chain from between the cassette and the spokes.

My suggestion would be to use a vice, or do you have one of those Workmate things?

The first thing I'd do is to break the chain and get the whole "wheel and chain" mess away from the frame. It just gives you more room to work. Then, I'd clamp the teeth of the cog in the vice (as I say, I've had good results with my Workmate). Then you undo the lockring, which admittedly can be fiddly. If it has been on a while it will be tight, as you have discovered, and you might need to use a mallet to coax it loose. (I have tried chain whips in the past too, but never even bother nowadays, a vice is far more efficient.)

If you don't have any way of clamping the cog, the only other suggestion is to take the wheel to a shop, who will use their vice to loosen it. With the right tools, it is really only a 30-second job so you may be able to sweettalk them into doing it for free.

Lastly, you should probably spend some time thinking about how this happened. Could be you just got a jump because the chain was loose, but it is probably worth checking your chainline to satisfy yourself that everything is ok.

You might also want to check your spokes for any damage from the chain.....better to replace them now, while you've taken things apart, than have them break later.


Just replace it. The part is called quill stem, it is not threadless-compatible, and it is still widely used. The only type of quill stems I heard of have 1 inch diameter, so you can just find one that is of the same/similar height and length.

The simplest is to take it to a local bike shop and they will do it for you. If you want to replace it yourself, get a wrench that can undo those two bolts at the top of your picture (hard to tell, but I think it is something in 12 - 15 mm range).

Unscrew the stem from the frame and from the handlebars; grease the new stem's shaft that goes into the fork with any sort of machine oil/grease you have; then screw it back into the fork and attach the handlebars.

It may happen that the fork-stem surfaces have rusted together if no grease was used at installation time. In this case, you will have a hard time removing the stem. Look for advice on this site how to help it.


Sorry for an answer that should be a comment (need to get my bicycles.SE rep up before it'll let me do it right).

I see (open the asker's image to view larger)...

A Marzocchi Bomber fork, construction and decals look like a late-90s Bomber Z1 (http://www.retrobike.co.uk/forum/viewtopic.php?t=198026, though slightly different from the pictured "bam" model).

An FSA headset.

A ROOX seatpost (http://www.roox.at/COMPONENTS/COMPONENTS/Seatpost_overview.htm, though I didn't try to find the exact model from as little as visible.

A Cane Creek rear shock.

Cheap department store bike was my first guess, but the identified parts seem a bit better than that for as little as I pay attention to who is selling their brand to junk bike makers.

Hope this helps!


My tires are 700x23/25C. What does 23/25 mean?

Some manufacturers (e.g., Specialize) offer two width measurements (e.g., 700x23/25c) to indicate that the carcass is 25 mm wide, but that the tread patch is equivalent to a 23 mm tire.  I believe this is done to create a more supple tire (larger volume tires can be run at a lower pressure) while reducing rolling resistance.

Another possibility could be to indicate width/height profile differences. A tire profile that is perfectly found tire will be the same in both. I don't know if any manufacturers are doing this.


Is it possible to avoid anaerobic 'burn' on ascents?

Get an app like strava to log your rides, and see your progress on those climbs.

I have a climb near home which took three hours first time I did it.  I rested a bunch of times on the way up, and got passed by dozens of riders.

Over the last three years I've improved to the point I can do the climb in 40 minutes non-stop, still get passed but I'm passing others, some of whom look shattered.

Remember it never gets easier, you just go faster.  Some logging will help show you your improvements, because it never feels faster at the time.


Choosing hubs and rims for training road wheels

Front hubs on mountain bikes and road bikes are all the same width, 100mm (except for some downhill hubs with through-axles). So you could use either type, they would fit in your forks fine.

Note nearly all current mountain bike hubs are designed for disc brakes, so include mounts for attaching a rotor. You can still use them on a bike with rim brakes, just don't fit a rotor. The disc part would increase the weight a bit, so they will be a bit heavier than an equivalent road hub. Also the disc mount means the hub is not symmetrical, so the wheel has to be dished. This makes it a bit more complicated to build, ie it needs different spoke lengths on each side. But this doesn't really matter, you can still build a strong wheel with either sort of hub. And disc mounts would be useful if you wanted to fit disc brakes in the future.

As for which hub, generally mid-range Shimano hubs are good. eg Deore or LX for mountain bike, or Tiagra or 105 for road. Usually they just work fine for years, with hardly any maintenance. Shimano hubs typically use cup-and-cone bearings, so they can be serviced, and the bearings replaced, but this may be a bit fiddly.


Would the shimano freewheel removal tool be roughly compatible with a Sram/shimano cassette?

The freewheel tool is of a smaller diameter to a cassette tool but the splines don’t fit the cassette lockring because the spline dimensions (width) don't match, as seen in this photo of the freewheel tool viewed through the back of a cassette lockring. The lockring is resting on the tool without engaging:

So you can’t use one tool for both, and modifying one to do so would be ineffective, I expect it would slip under torque.
Whilst it might be possible, depending on tool & lockring tolerances, to hammer the freewheel tool into a cassette lockring, I wouldn't do that myself; the correct tool doesn't cost a great deal and saves damaging tools/parts.


The Good or less worn tire should go on the front wheel as indicated in this Sheldon Brown Article on Tire Rotation
Although the article does hint to the fact that you should not be really rotating tires to the front wheel that may have been used on the rear wheel.

The only time tire rotation is appropriate on a bicycle is when you are replacing the rear tire. If you feel like taking the trouble, and use the same type of tire front and rear, you should move the front tire to the rear wheel, and install the new tire in front.
The reason for this is that the front tire is much more critical for safety than the rear, so you should have the more reliable tire on the front.
If you have a blowout, if it is on the rear tire, you have a very good chance of bringing the bike to a controlled stop. If your front tire blows, you can lose steering control, and a crash is a real possibility.


Does chain tension change how hard/easy it is to pedal?

If the tension is too high, the drivetrain will bind. If it is too low, the chain will drop (which is dangerous on a fixie, since it can catch and lock up the rear wheel relatively easily).

You basically want the highest tension such that the drivetrain doesn't bind.

See Sheldon Brown on how to set chain tension properly.


Seems like I'm a Necromancer again...

Most likely a spacer. No, I take that back; Almost certainly a spacer. With the Hybrid cassette fitting correctly, it's quite often that they are slightly thicker, even by a couple of millimeters. An easy way to check is to check the limiter screws on the deraileur if you haven't adjusted them. If there's too far away from the wheel for where the jockey wheels line up, it's probably missing a spacer. If not, it needs a thicker spacer or more, assuming the gears were properly set up before you took it to pieces.

Also, good call, taking the cassette off to clean it. Too many times, people leave it on their wheel using a degreaser to clean it, and it breaks down the grease inside the hub and freehub body! Annoying because I usually get asked to replace them when it happens, then I lecture them about all the problems from doing so..... Boring!


Is it safe to attach a flashlight to a helmet?

All of the mounts from reputable manufacturers thatI’ve looked at are either rubber or Velcro or have a quick release that’s designed to tear free on impact.

Paracord is incredibly strong - some have a tensile strength of over 200 kg /550 pounds.

The concern is that your head might hit an object (such as a low tree branch) and the light or mount will snag on it, whipping your head and neck back. The neck vertebrae don’t like this motion.

Also, in an accident the helmet is designed to slide along the ground preventing torque to the head. Your paracord might also snag and cause the helmet to torque your head.

Note it would take a freak accident for this type of injury to occur. An individual might be fine with accepting this type of risk personally. A manufacturer who has domestic assets that could get seized in a lawsuit might not be willing to accept the risk, thus they err on the side of caution. On this forum, we can’t say “it’s fine” — that’d be negligent but we could say that many people would find the risk acceptable but ultimately it’s your call.

Tl;dr: ideally, you’d want your mount to have a full break-away design.


what's the reason for different front and rear tire sizes on a XC MTB?

Yes, it is common on mountain bikes to have a wider front tire.  This is to avoid "washing out" in corners.  Plus the extra air volume provides more cushion and increased comfort for your hands (even if you have suspension).


Failure in venerable spoke at nipple: causes?

If a spoke breaks, it'll go at one end or the other, because that's where the stresses are concentrated. Breaking at the nipple end isn't particularly unusual so I'm not sure there's any specific cause you should be looking for. (Both the spokes I've broken went at the nipple, for example.)


Upgrading 8 speed shimano Acera RD-M3000 to 11 speed Deore XT M-8000?

Yes, as long as your bike has normal 135mm spacing, there's no obstacle with frame spacing or other frame compatibility. Despite the addition of new rear end/spacing standards, compatibility with standard 135 QR frames hasn't been dropped.


I purchased a "new" bike from my local bike shop that is five years old--should they have disclosed this?

If it's actually used, as in previously owned with real mileage, they should have disclosed that. If it's in new condition, or new condition with some amount of the discount being for shop wear or due to being a low-mileage return, then I would say there's nothing disingenuous about omitting the manufacture date unless asked directly.

For better or for worse, it's not the standard practice in bike shops to include the model year on the sticker, as is seen for example on a car lot. Maybe it's a reasonable question whether that makes the whole industry that much scummier, but following the practice doesn't make any particular shop especially scummy.

Many who work at or run shops don't have great feelings about the industry's general insistence on model year cycles. The way it tends to play out is the model year cycle is one of the back industry's tools to generate sales based on perceived obsolescence, whereas we in shops know if a bike was good and worth standing behind 5 years ago, it very probably still is today. Meanwhile, however, the model year cycle creates a need in the retail environment to constantly worry about selling through stock before it becomes last year's model, an artificial panic which really doesn't do the retailer any good in the end. This is only to give some background about common attitudes in shops on the topic.


How to store a bike outside and still avoid rapid decay?

A small shed seems like the best option if you have space–some insulation inside the shed would help stop condensation.

A bike kept outside will rust given enough time, its gears, etc. will also not like being wet all the time.  Just as importantly, it is more likely to get stolen if it is just left outside, and I would always rather get on a dry bike than a wet/cold bike.


Fixing rear-wheel puncture on belt-drive bike

It looks good except I think you will have to loosen the tensioner. You won't have to spread the frame. When the recessed allen head bolts are removed you risk damage to the very end of the threads due to the belt tension. It is unlikely you can reinstall the tensioning assembly with tension on the belt. Due to the complexity of this kind of flat repair you may want to consider some type of puncture prevention be it tires, tire liners etc. I have used a technique of repairing a puncture without removing the wheel. In this case a rider on my local trail had a flat, bolt-on wheels, and no wrench.  You flip the bike upside down. Work one edge of the tire off the rim. Pull out the tube and patch and replace as usual.  Instead of working your hands around the wheel you spin the wheel as you work your way around. It appears in the photo that you may not have to remove the shifter cable. There may be enough slack to work it around the frame and effect the repair.


Rough up the paint with sandpaper, and then use Aircraft Remover to get the paint off, if you try to sand it, you'll go crazy. DO NOT use aircraft remover inside, and wear a filter mask, it will make you sick if you don't. It will rip the paint right off.

http://www.rustoleum.com/product-catalog/consumer-brands/auto/paint-chemicals/aircraft-remover


It's a legit company. Many of the bikes they sell are not really name-brand bikes—they're house brands. As I understand it, Mercier and Windsor are old bike marques that went defunct, and BD bought the names and sell their bikes under those names. There is a certain misplaced snootiness about this, since almost all these name-brand companies outsource their manufacture to a few giant factories in China or Taiwan and slap their own decals on. BD's other bikes are remainders from other companies, I think.

Many of their bikes skimp on the specs, substituting lower-cost parts in places you won't notice (like the bottom bracket). Of course, lots of name-brand makers do the same.

Finally there's the assembly. I don't have direct experience with BD bikes, but I've read unkind things about the quality of assembly. Since you're buying a pig in a poke when you buy mail-order, you don't have a chance to see if the wheels are true and evenly tensioned, that sort of thing. In that respect, you really are getting something worse than you'd get from a reputable local bike shop.

If you know what you're getting when you order, they're fine. But you could be buying a bundle of problems caused by poor assembly. You're definitely not buying name-brand cachet. And might not be buying a bike with quite as good specs.


Last no helmet ride in the Tour de France

Helmets were entirely optional until 5 May 2003.
On 5 May 2003 the following rules were introduced https://web.archive.org/web/20160304090208/http://oldsite.uci.ch/english/news/news_2002/20030502i.pdf

During competitions on the road, a hard shell crash helmet shall be
worn. Except where there are legal provisions to the contrary, riders
taking part in international events for elite men of class 4 and above
may, at their own risk, remove their helmet during the final climb
when the finish of the event or stage is on or at the summit of that
climb, subject to the following conditions: 1) the climb in question
is at least 5 km in length, 2) the helmet may not be removed before
the start of the climb,
3.2 Rider taking the start without the required helmet

Elite men's road races in class 4 and above 200 to 10 000 [CHF fine], plus 50 points deducted from the UCI individual classification [a TdF win is 1000 points]
Other cases: start refused

3.3 Rider removing the obligatory helmet during an event

Elite men's road races in class 4 and above 200 to 10 000 [CHF fine], plus 50 points deducted from the UCI individual classification
Other cases: expulsion from the race and 100

Therefore helmets were mostly compulsory, but elite riders could remove the helmets legitimately on a climb, however they had to be retrieved immediately by a team member.
This rule was certainly in place for 2003 & 2004 https://web.archive.org/web/20040804001045/http://www.letour.fr/2004/docs/reglement_us.pdf
This was changed either on 1 August 2004 (post 2004 TDF) or 1 January 2005
https://one2onecad.files.wordpress.com/2013/02/uci-bike_-equip_-regs_.pdf

Except where legal provisions determine otherwise, riders taking part
in UCI WorldTour events may, at their own risk, refrain from wearing a
helmet during individual time trial races taking place entirely on a
mountainous course. Every discussion regarding the qualification
«entirely on a mountainous course» will be decided by the
commissaires’ panel.

This meant that organisers COULD designate a climb where helmets were not required, but this was not necessarily the case.
It appears from video evidence that for 2005 helmets were optional on certain climbs, but from 2006 onwards this was no longer the case.
The provision was deleted entirely from 1 January 2015
http://web.archive.org/web/20180716223921/http://www.uci.ch/mm/Document/News/Rulesandregulation/16/80/73/1-GEN-20150313-E_English.pdf


What are the pros and cons of suspension seats and suspension handlebars?

Suspension seatposts and stems have relatively limited travel--I think most suspension posts have about 20 mm of travel--so they're not so much intended to absorb big bumps as iron out road buzz.

Most suspension posts and stems are heavier (perhaps not so heavy as to bother you), more expensive, and sometimes more finicky to set up.

You're already running pretty fat tires, although perhaps you could go up to 2.5" ones. According to the tire pressure optimizer it looks like you could use 40 psi in back and 24 psi in front, which would smooth things out a bit. There are some light-casing tires that are noted for giving a smoother ride (they deflect more readily around road irregularities), although I would hesitate to recommend them for riding over bad roads.

It's hard to answer specific questions about your bike without knowing more about your specific bike.


How can I remove the small slitted nuts to open an old rear hub?

With an angle grinder and a flat file you can easily make a tool for this purpose from flat iron (preferably hardened):

If you use hardened flat iron, make sure to spray or dip it in water regularly too not lose the tempering when grinding. The small tip that fits into the slit of the nut needs to be finished with the flat file since the angle grinder doesn't reach to make it the right angle.


Can riding without a chain damage a bike?

What harm could it possibly do? The cranks are held firmly in place by the bottom bracket; the back wheel is held firmly in place in the drop-outs. The chain is completely non-structural: all it does is transmit power from the pedals to the rear wheel.

The only issues I can think of are

make sure you know how to remove and replace it, obviously;
I pretty much guarantee that you'll fall off at least once because of this. You know, as an intrinsic part of riding a bike, that putting forward pressure on the pedals has various effects and you use those effects subconsciously to control the bike. Now you're riding a bike where putting forward pressure on the pedals just spins them with no resistance. But, hey, you're practising tricks so I assume that falling off isn't a deal-breaker. :-)

Benedikt Mokroß adds

You're going to hit your knee on your stem a lot. Been there, done that.


A tubeles plug will not hold in a bicycles inner tube.

A tubeless plug is a short string of butyl rubber. About 1 cm in length and 2 mm wide. To fix a punctured tubeless tyre it is pushed with an awl into the hole. Together with sealant in the tyre it is good to seal cuts of up to 5 mm.

The inner tube's walls are too thin and too stretchy to seal it that way. The reasons are similar to those in my answer on sealants in inner tubes: https://bicycles.stackexchange.com/a/64642/30402

Fixing a clincher tyre that contains an inner tube with such a patch will not seal the puncture. Air would still escape through the valve hole, gaps in the rim, along the tyre bead, and countless other spots.

Fixing a small hole in clincher tyre when an inner tube still holds air is not necessary. The tyre itself doesn't need to be air tight. It just needs to hold the tube inside and provide a good contact patch to the ground. The plug cannot fix large holes in a tyre (check tyre boots). In such a case the threads of the carcass are ripped and the tyre loses the strength it requires to resist the pressure of the filled inner tube.


Rear derailleur hitting spokes in 4 largest cogs

Your problem is the thick sheet metal derailleur 'hanger' is in fact badly bent. On cheaper model derailleurs the hanger is built into the derailleur rather than the frame.

Don't ride it in this state, the derailleur getting caught in the spokes will smash it and probably damage the wheel too. Also the chain may catch in the cage with similar results.

You should be able to take the bike to a repair shop and get professional and courteous service, no matter what bike you are riding. Your money is as good as anyone else's.

If you want to address it yourself, all you have to do is bend the derailleur back. If you turn the bike upside down (on something soft that will not mar the seat or bars) you can look down the line of the chain. The derailleur cage should be parallel to the chainrings. Hold the derailleur at the top, not by the cage, you don't want to bend it.

You do want to be careful because the hanger will only be able to take so much bending before it get weakened.


turbo trainer on wtb 27.5 sx19 wheel is it possible

Trainers are hard on bikes and on tyres/tires.  You want a cheap hard-wearing tyre for the rear.   Grip and tread are mostly irrelevant, and even a mostly worn tyre is probably fine.  Get every bit of usage out of the rubber.

Some people choose to have a spare rear wheel to swap out for convenience, because that's less work than swapping the tyre.

Others have a dedicated trainer bike permanently mounted in the trainer. Sometimes they even have no front wheel, purely for space saving.

Aside - Consider setting up a fan to replicate the passage of air.  Its hot and sweaty working on a trainer without airflow.


What's the real difference between cheap and expensive helmets?

No, usually expensive helmets are lighter and more comfortable because have more ventilation.

So, if you plan to ride for long hours it's better to buy the more expensive helmet that you can afford, otherwise - for short rides - a cheap helmet will do the job.


How to protect rear derailleur while mountain biking?

They make bash guards for derailleurs which mount to the frame which protect a derailleur in a crash like

but these are dangerous in that they transmit a hit to the derailleur to the frame (and frame damage is typically less repairable/ more expensive than a derailleur damage).

Usually, what gets damaged in a crash is the derailleur hanger, which can be bent back into shape with a special tool at your bike shop (Park Tool DAG-2 for example). You should never pull the derailleur into shape by the cage (this is the weakest part of the derailleur and can damage it more). On non-steel bikes, this is often a little replaceable part which is designed to deform in a crash so hopefully your derailleur makes it out alright as does your frame (so if you can't bend it back into shape, you can replace it).

Typically the Shimano Deore level is what gives you the best hit taking ability for the price, though it depends on how you fall and how the derailleur gets hit and stuff. The best thing to do is "don't fall". But obviously, compatibility within brands and budget dictate what to buy.

I'm curious as to how the derailleur is "bent", and how you're straightening it though. It would be good if you updated your question with a diagram or picture of your "bent derailleur", along with the type of bike you're riding.


Torque wrench specs & features for small to medium jobs

Would a beam style wrench be just as good, or more suitable than a click-type?

Definitely not. With a beam-style wrench you have to accurately observe where the pointer is on the scale. That means you have to be looking straight-on at the scale. Bicycle bolts are at all angle and orientations, which means looking at the scale will be very awkward.


Any experience about radially-laced hub flanges actually breaking?

While it is possible for a hub flange to fail due to radial lacing, if the wheel is built properly, to proper tension, it doesn't happen, generally.

The reason it happens is because the amount of material between the spoke head and the edge of the flange is least when the spoke is pulling directly to the edge.  Under normal usage, the flange has more than enough strength, even when laced radially.

However, if the wheel is laced with too much tension, or if the wheel is placed under abnormal stress, like when used for braking on a fixed gear, then the hub flange is more likely to fail when radially laced, than when laced with a proper crossing pattern.

It can still fail, even when crossed, but it is far more likely when laced radially, due to the smaller amount of material, and more direct tension on the flange.

I have used radially laced wheels, mainly for BMX racing as a kid,  I have had only one failure of a hub flange, though, and that was on a Bontrager Race XXX Lite rear wheel in 2003. That wheel uses a radially laced, paired spoke pattern, which I do believe contributed to the failure.  They are also excessively high tension wheels, due to the low spoke count, and I think it took both the radial pattern, and the excessively high tension to cause the flange to break.

I hope that helps.


Does changing the clipless pedal float change the speed of disengaging?

Although it would make unclipping faster, there are a few other things you can tweak to get the same effect without changing cleats.

Maybe you need to reduce your clip tension so it takes less force to unclip.
Practice the instinctive clip-in/out. You really don't want to have to consciously think about "I need to unclip NOW". Rotating your feet outwards needs to be subconsciously linked to your "danger is imminent" response. Riding MTB with clip pedals is a good way to learn this habit.

Changing to a more restrictive cleat will require you to be much more precise with your cleat setup as the comment says, for fear of knee injury or even worse, reduced power. You might also not like the lack of float compared to the yellow cleats. On the contrary, you may realize you actually prefer less float, making it overall a win-win situation.


Can't really tell much by your video. We see you clicking up & clicking down, but you don't appear to be turning the cranks. The gears will not shift unless the drive train is in motion.


How has hardtail MTB geometry changed in the past 10 years?

I'm not sure about the geometry, I doubt that it's changed much. But I suspect that the question you really care about is in your last sentence.

You've got a perfectly good bike, other than the busted fork, and it fits you. A newer bike will perform better, but it won't be a huge difference. If you haven't ridden off-road in 5 years, your atrophied skills will be holding you back way more than your equipment.

If you want to buy a new bike, and you have the cash, then by all means do it. But don't let them con you into believing that everything becomes obsolete when the new model comes out.


I keep breaking the tips off my presta tube stems

I also use a Joe Blow on my prestas.  After I had a couple valve stems bend and/or break, I started making sure I only unscrew the stem a little bit.  My theory was that by unscrewing the stem all the way up, it was easier to bend or break when pulling the pump head off.  Haven't had it happen again since.


Are Shimano R7000 chainrings (50 and 34T) compatible with Ultegra R8000 crank?

Yes, they are 100% compatible. See https://si.shimano.com/api/publish/storage/pdf/en/ev/FC-R7000/EV-FC-R7000-4331A.pdf https://www.bike24.com/p2284436.html
R7000 & R8000 chainrings are a 'B' match, that is different materials but compatible.
With a 50/34 compact, then the rings are 'MS' pattern. Previous generation are 'MA', which is incompatible.
There is a high chance you can use the even cheaper/heavier RS510 chainrings, which are also 'MS', however I haven't seen that confirmed.


Replacing rims with a 3mm effective diameter difference - can spokes be reused?

It is completely normal to replace a worn out rim by transferring the existing spokes to a new rim - it's slightly easier than relacing the wheel, since you can tape the rims together and transfer each spoke one by one (slacken off the tension on all the spokes of the old wheel before you start!). A 3mm difference in ERD will correspond to about 1mm in ideal spoke length - unless the existing spokes were too long (ideal is top of spoke at bottom of screwdriver slot) this shouldn't be a problem. Washers under the nipple heads (eg Sapim polyax) would help compensate if the spokes are on the long side. Going the other way (smaller to larger ERD) too-short spokes can be compensated for with longer nipples - although for a 1mm difference I wouldn't bother.


This could be due to the cones on the axle coming loose. The cones screw onto the axle and prevent play in the bearings. If they are too loose the hub will be able to move independently of the axle. If they are too tight the wheel may not turn freely and you may damage the bearings by crushing them. See here for more information on how to properly adjust the cones.


What are the best MTB Tennis Shoes ? (without clippers)

You should look for shoes with as soft outsole as possible. Ones specially made for cycling are available from bike stores, labeled "downhill mtb shoes". Skateboard shoes and approach shoes from climbing department also work well, choose one that fits your style.


Chainring offset - chainline - of Alfine vs. Ultegra/Dura Ace

The Alfine has a chinaline of 42.7mm for a single crank and the Ultegra 43.5mm for the double and 45mm for the triple.

For the double the chainline is measured halfway between the 2 rings so the outer ring will be even further out, but the inner further in.

Sheldon says "With typical 5 mm chainring spacing, this puts the inner at 41 mm, the outer at 46 mm".

1.7mm or 3.3mm both sound like a long way for a belt drive to me. But I'm not an expert there. You my be able to use the BB spacers to offset the whole crankset 1.7mm towards the drive side, but I'd rather not go down that route.

This is all assuming there's no extra molding on the cranks or rings to get in the way.


What makes WD40 work well for grip installation?

Any liquiid-fluid works for grip installation.  The liquid temporarily decreases the surface friction between the grip and the bar, and then departs.
Personally I use soapy water which evaporates over time, leaving the slightly tacky soap behind to discourage twist in the grip.
WD40 has some mild petroleum products in it which may damage some rubber compounds. I've never seen that myself, but I don't spray WD40 on grips either.  This might subtly texture the underside of the grip at a microscopic level (this is a guess)
WD40's lighter components would flash off over some hours, leaving behind the waxier protectant layer which acts as a weak glue, same as the soap I use.

My other tool for removing grips is a very long thin flathead screwdriver.  Poking it in at the end between bar and grip allows a channel for the fluid to move along the length of the grip, where it dissolves the residue from installation. and some sharp twists makes the grip loose all the way around.


Why is lactose never mentioned as a fuel for cycling, either for short fast races or endurance?

Glucose (dextrose is the same thing) has a special role in metabolism - as well as being a nutrient sugar in its own right it's a vital intermediate in breaking down more complex sugars, starch, and glycogen, our bodies' main store of carbs.  This all means we're able to get energy from it very efficiently (excepting cases of diabetes).  This is why energy drinks (the ones with calories in, not just caffeine and flavouring) use it.
Maltodextrin, used in energy gels and some energy drinks, is pretty much just a string of glucose molecules.
Fructose is metabolised rather differently, but the pathway is connected to glucose metabolism, so it's not exactly parallel.
Sucrose is a glucose and a fructose joined together, so also a very available source of energy.
Lactose is broken down by lactase (in those individuals that produce it) into glucose and galactose.  The latter in turn then ends up as glucose by a variety of routes, probably slower release than glucose, but faster than starch. It would appear to offer no advantage as a parallel source of energy to glucose, while not being any cheaper and intolerable to some people.
So if you like it, you can certainly get energy from it, and milk can often be bought easily - on a recent warm ride it would have been the only way for me to get a chilled non-alcoholic drink in one shop (but I don't like it as a drink so I had an ice cream and water instead).  For a manufacturer trying to make money, it would make their products more expensive for no sales benefit.