Do OnGuard MinPin Locking Skewers provide adequate security?

I haven't used them myself, but I've been asked to remove a broken set. A customer came back to their bike and discovered that a thief had tried to force them and failed. But not before breaking both front and rear lever mechanisms. I got both off without damaging the rest of the bike at all, with a cutting disk in the grinder they come off in seconds. Anyone can buy a battery grinder for $99 and youtube has a collection of "bike thief being ignored" videos so I'd rate these as "casual thief" resistant.

Also, the "locked" mode is exactly like the "stuck" mode of a normal set of QR skewers. Unless someone knows that they're the special locking ones they'll just apply more and more force until something breaks. So every time you take it into the bike shop or put it on a vehicle you will need to attach a note to the bike to that effect. I hope they come with stickers or something.

Given that you're looking at spending money at all, I suggest something more effective. A  set of Pitlocks cost about $105 from Peter White (US) or 95 euro from pitlock.de. And they're made from hard stainless steel so a cheap battery grinder will take a long time to grind one off.


Is it normal for an Inner tube to bulge when inflated?

Yes, inner tubes do that. They are like balloons, except that the butyl rubber they are made of doesn't stretch like natural latex rubber.

You are not supposed to inflate tubes outside a tire. Tires have fabric casing to withstand the pressure.


Can I put my 2.1" 29er tires on a wheel with 25mm inner diameter?

According the Sheldon need 25mm for a 2.1"

A downhill wheel tends to be strong (and heavier)


Either the L screw which limits how far the derailleur can move towards the wheel is too far in or the cable tension is too low.

Try to increase the cable tension first by turning the barrel adjuster on the derailleur counter-clockwise. However, it looks like it’s already pretty far out. If it’s at the maximum you have to shift to the smallest cog (highest gear), screw the barrel adjuster all the way in, unclamp the cable, pull on the cable as far as possible (pliers help) and then clamp it again.

If the cable tension doesn't help you have to turn the L screw counter-clockwise to allow the derailleur to move farther. Don't turn it out too far or the chain will fall over the cog into the spokes.

Park Tool offers a good tutorial here: https://www.parktool.com/blog/repair-help/rear-derailleur-adjustment


Are single-speed bikes better equipped to handle cog/chain wear?

I'd transform the comparison between single-speed vs. multi-speed (derailer) to SINGLE-CHAINLINE (single, fixed, or internal-geared-hub) vs derailed (assumed always multi-speed).

Then, there are ONLY advantages for the single-chainline bike:

Overall material is thicker. On the other hand, the need to pack a lot of gears in a cassette requires that the cogs are relatively thin, and so the chain, and that means wearing out faster.
Chainline is usually away from the rear wheel. On the other hand, the lower gears of a derailed bike make the chain get very close to the rear tire and get more dirt (MUCH more dirt in case of a fat-tired knobby mountain bike slowly building up mud during an off-road climb in the granny gear).
The chain doesn't catch so much road grime, (because) in the other hand, derailed bikes literally rub the chain against cogs in order to shift. Also, the cogs that ARE NOT being used keep exposing their oiled surface to the elements, gathering dust and putting it in contact with the chain as soon as it is shifted to that gear again.
The chain is always in line, so theoretically there is an even stress on the pin/inner-plate working surface, that's where the wearing happens after all.
It takes at least double the time, work and cleaning materials to clean a derailer drivetrain compared to single.
As already said, a single-chainline drivetrain can be enclosed.
Single-chainline usually won't skip when you install a new chain.

So, I would say that for COMMUTING or for utility use in general, a single-geared or internally-geared bike are excelent choices. I have both setups and don't regret.

I don't regret giving up gears in my fixie because it is lightweight and efficient, and I can go fast if I want, and go up most hills if I want (of course not at high speed then).

And I don't regret throwing some serious money for an internally geared hub, because the original cog lasted for at least 20 thousand kilometers, and I saved A LOT of tinkering with the drivetrain (such as cleaning, adjusting, and replacing parts).

Hope this helps!


What format should I select for automatic upload to Strava?

TCX and FIT are designed for fitness activities, so they can contain more fitness data than GPX.

eg TCX or FIT supports laps (splits). So your device could record a new lap whenever you press the lap button, or automatically after a set distance, eg every 1km. Also they support pauses, if you want to stop the activity at one point, then start again later. Whereas GPX is essentially just a series of points (with timestamps).

I am not sure whether Strava actually uses the laps or pauses recorded on the device, I suspect it will recalculate them anyway, based on the GPS points and time.

As standard, GPX does not support heart rate, cadence or power data. But this can be added with extensions. The most popular format for these extension was created by Garmin, it is also supported by a variety of other software/websites (including Strava). But some devices might record heart rate/cadence in a different format in the GPX file.

TCX or FIT can also contain summary data, for the whole activity. eg the total time, distance, calories, device used, type of sport. Some of this is used by Strava, eg to display the device, or automatically select the activity type.

TCX and GPX are both XML formats, which can be fairly inefficient in terms of file size. But this does mean they can be easily edited, eg in a text editor. FIT is a binary format, so is much smaller file size, typically about 1/10 of the size. File size is usually not a problem anyway - even if you are recording at 1 point per second, a 3 hour activity would be about 1MB in GPX format. So not really an issue, unless your device has very limited memory, or a slow internet connection for uploading.

So in general, you probably won't notice much difference between formats for uploading to Strava. Though TCX or FIT may give you a bit more data. And FIT would be a smaller file size.


Tall rider - good cockpit/body position for downhill

Are there other aspects that are causing you to position yourself wrongly on the bike?

I was taught that to get the best brake angle you should stand behind the seat, feet on the floor and reach for the bars. Extend your fingers forward to continue the line of your arm and the lever should be rotated to touch under your fingers.

I'm a short person so I'm not that qualified to say how a tall person should alter things but beware of over-reaching. As mentioned before, you'll get a more direct feeling from your steering with a short stem but a little less stability. I wouldn't go for a longer stem personally.

You may be able to raise your bars a little if you have spacers above your stem. Failing that, so you have a bike shop locally that would let you borrow an ex-demo or second hand bar? Could you try some bikes out in a shop to get a feel for reach? Some shops have turbo trainers that could at least give you and idea of how different frame sizes feel.


They very likely were talking about your front shifter's trim stops.
Your shifter has 3 or 4 positions despite there only being two chainrings. As you shift around in back, the angle that the chain enters the front derailleur changes. This can cause rub. The trim stops exist to change the front derailleur's position enough to eliminate the rub. In other words, when the system is set up correctly, you've got one or two stops in it that shouldn't be moving the chain. (Almost every STI now has 4 but I'm blanking on whether Claris is 3 or 4.)


Norco 7.1 charger with rockshox 30 gold tk. Can I upgrade to rebas

3) If changing a fork, you should aim to have the same effective length when riding.  If your fork ends up longer, its able to exert exponentially more force on your head tube.

Also, a longer fork will raise the front of the bike effectively slackening the head tube angle and giving you more trail.   The rake angle of the new fork may also add or reduce trail.  Either way, yes changing fork is likely to change handling.

Ideally you want the bike to have the same silhouette from the side before and after changing the fork.

Breaking that down, you want the same trail measurement before and after to keep handling the same.  The top tube should be the same angle from the horizontal before and after, and the wheelbase should be the same.

If you fit a longer fork with the same size wheel it will look more like this.  Note this is 2 degrees of rotation centered around the rear axle.

The upshot is there is now more trail, so your bike will resist turning more, until it gets to about 25 degrees of steering input and the front wheel will then try and turn sideways hard, because it wants to "fall over"

Upshot, you want the trail value to be identical before and after, and ideally the forks no longer than original.


carbon vs aluminium frame vibration absorption? bumpiness?

Aluminum has gotten a bit of a bad reputation from the early generation of frames which were overly stiff. This is less the case today as manufacturing technology fixed most of these earlier problems, and bicycle designers can create formed aluminum tubes that provide compliance (i.e., vibration absorption) in one direction (e.g., vertical compliance) and stiffness in another direction (e.g., lateral for power transfer).

Aluminum frames are actually an alloy (mixture of metals) and the there are a number of different alloy composition available, with each having different metalergic properties (e.g., stiffness or compliance, strength, etc). Frame manufacturers tend to choose an alloy that suits the intended use of the frame so they will often use a mix of alloys across their frame lineup.

Tubing shape also has an impact on vibration dampening. Earlier generations of frames that were famous for being overly stiff used relatively straight tubing.  Modern frames often use hydro-formed tubes that have carefully crafted shapes to produce compliance in one direction and stiffness in another.

Essentially the compliance you feel in a modern aluminum frame was likely intended as a design feature by the manufacturer or the result design constrains such as cost.

Carbon is not a panacea for compliance either as the ride quality of carbon is directly related to the layup process (i.e., how layers of carbon fibre are compiled together with epoxy).  This is a very expensive and labour intensive process, where it is easy for manufacturers to cut corners in order to save money.  From the outside most (everyone?) cannot tell what, if any corners, were cut.   In the end the compliance of the frame is directly related to the manufacturing process, just as it is with aluminum.

Similar to aluminum the compliance you feel in a modern carbon frame is the compliance intended as a design feature by the manufacturer or the result design constrains such as cost. You will have to ride the frame to see how it performs.

Now if we go back in time to the 80/90's both the carbon and aluminum frames, which both employed relatively straight tubing (earlier carbon frames had straight carbon tubes that were glued into metal lug joints), then yes as a general rule carbon was more compliant.  If we compare modern frames (of similar quality - key point) from the same manufacturer with the same intended use case (another key point) then the gap in compliance will likely be quite small.

GCN has a good video overviewing a lot of the points mentioned above.


Not able to get crank bolt into bottom bracket spindle

The picture of the left side of your bottom bracket without the bolt is not real clear, but I wonder if there's a round obstruction partially blocking the opening and preventing the threads of bolt and BB from engaging. Normally there is a mm or 2 of unthreaded counter-sink at the beginning of the spindle's hole prior to the threads beginning.  While it could be a photographic anomoly, I could see some of that counter-sink--or some threads themselves--galling and upon removal of the original bolt, get spun up at the opening, creating a partial blockage. That would cause the symptom you describe.

At any rate, here's example of a replacement bottom bracket (not a recommendation).   You'll need to select the correct length of spindle, but as you see, they're relatively inexpensive and replacement is appropriate regardless of the reason the bolt won't engage.


How to store bicycles outside during winter

Here's my solution.  Take off wheels, pedals, and handlebars, and place the bike under the bed.  Ok, that may not be the right solution, but it might point you in the right direction.  If you start taking parts off your bike, you can fit it in a pretty small place.  You might even want to consider taking parts off and storing everything but the frame inside your apartment.  Take out the bottom bracket and leave that in the house.  Wheels can be easily stored inside.  The seat/seat post is dead easy to remove and can be stored just about anywhere.  Basically you should store as much inside as you can.


Does changing gear relation produce different speed at same applied power?

Yay! Another physics question.

Restating the question: if the rider power input is constant, does the bicycle velocity change if the drive-train gear ratio is changed?

Let's assume the road surface, wind speed, gravity etc. all remain constant. Bike and rider are on a surface with no gradient.

Short answer is that constant power results in constant velocity regardless of gear ratio. Gear ratios change angular velocity and torque but because the product of the two is constant power remains the same.

Power at the rear wheel = power provided by rider - power loss in drive-train.

If the power loss in the drive-train does not change with gear ratio selected, the power at the rear wheel does not change and hence velocity does not change.

Of course, the power loss in the drive-train will depend on the gear ratio selected to some degree. I believe the chain travelling more slowly around a larger sprocket consumes less power (I'm not sure on this so somebody please correct me if I'm wrong).

However the power needed to overcome air resistance and wheel rolling  resistance is much greater than drive-train losses (if the velocity is not very low), so a change in drive-train losses will not effect velocity very much.

Update: addressing this statement from the OP (edited), as I think it's crux of the misunderstanding.

...with a smaller [rear sprocket] you obtain [higher] velocity than with a bigger [rear sprocket], applying same human power...

That would be true if human power was replaced with pedaling rotational speed.


Compatible heart rate sensors for CC-RD420DW

Cateye uses proprietary sensors, so I'm afraid that generic ANT+ sensors won't work.  Although it's possible someone has made a copycat sensor that works with Cateye, I doubt it.


My experience as a bicycle mechanic in the Netherlands: don't mess with it.

If it is an Shimano, it will probably run >100.000 km. If it is a Sturmey Archer, SRAM or any other well known brand, it will mostly do >50.000 km as well.

If there is a small hole for lubricant, only do this once a year or so, with some thin grease, but not oil. Oil is to thin.

If it doesn't shift well, first look at the cable. You probably only need to adjust the tightness of the cable. If this doesn't work, de-attach the cable. Every hub must work correct in the smalles or biggest gear without a cable attached. If this still doesn't work, the hub is broken. (Happens almost never.) If a 3-gear hub is broken, it is easy to take apart and build together again. And finding which gear or bearing is broken isn't difficult either. Finding a bearing balls is easy to, but finding a spare gear is probably not so easy.

Main point: leave it as it is.


It should be easy to replace your wheel. The wheel is a 26" (this is a standard mountain bike size wheel), and you will also need to match it to the right cassette. from looking at your bike, its likely a 7 or 8 speed cassette. Your local bike shop should be able to tell what size cassette you need based on your rear deraileur, which wasn't stolen. With wheel, tire and cassette you are probably looking at a $100+ repair if you buy it all new. If there is a local bike co-op in your area that can help you with used parts and labor then you can probably do this for $30-50.


Does frame size inside a particular model affect the ride characteristics of the bike?

The idea here is that a frame is typically originally designed in a 56cm frame, or the equivalent median size for the "average size" rider.

When the frame design is tested and finalized, most manufacturers minimize the changes they make when creating the molds for additional sizes.

This can result in small sizes having a harsher ride than the median, and large sizes having a softer feel, and slightly less power transfer. This is accentuated by the fact that most riders on a small frame have less weight and mass with which to flex the frame, and larger riders have more.

Really high quality manufacturers, like Storck bikes, for instance, use progressively shaped and manufactured tubing, which allows for the ride on the smallest frames and the largest frames to have the same ride characteristics of the median original design.

I am not personally familiar with the manufacturing techniques of Pinarello bikes, but their unique frame and tubing shapes would indicate to me that they would need to design each size independently, which would give a consistent ride characteristic, regardless of size.

Pinarello is known for the stability of their ride, but also for having a heavier than average frame weight. A 56cm frame is typically around 1800 grams, while the Scott Foil or the Storck Fascenario 0.7 G2 are 1050 grams and 1200 grams respectively.

It is more important that the ride characteristics match what you want from the bike, than how much it weighs, of course.

Have you ridden and been fitted on the bike you plan to buy? If not, do so first.
(Full disclosure: I manage a shop which sells Storck. This is not an ad, but it is why I'm familiar with the topic.)


Absent some kind of abuse or extraordinary stress (like falling on top of the bike while it's lying on the ground - stressing the tubes from the side, riding with a friend sitting on the top tube...) a carbon fiber frame should outlast the rider.

Lennard Zinn covered durability of Carbon Forks for Velo News a while back.  Here are some quotes from that article in case the link breaks:

From Kestrel

  For carbon forks in
  general, there should not be any
  limited life span, as carbon
  composites themselves are not subject
  to fatigue failures as metals are. So
  the fatigue life of a properly made
  carbon composite is 'infinite'.

From Look

  There is no limitation because carbon
  has a natural flexibility. It can be
  used a hundred years while maintaining
  the same stiffness.

From Easton

  The good news is the fatigue life of
  carbon fiber is immensely more than
  that of metals. While the writer
  expresses concern about his carbon
  fork lasting as long as a metal
  component, there is nothing to worry
  about in terms of fatigue life on a
  composite fork.

Having ridden since the early 80's I've been through this twice, once with aluminum frames and now with carbon fiber. As high end competition bikes were made of the materials there were questions of durability.  Over time, as the frames became widely available, those concerns were shown to be largely baseless.

I believe most frame builders warranty carbon frames for life now. I personally know of at least two riders with carbon fiber bikes that have been ridden in excess of 100,000 miles.

That said, you should periodically inspect the frame for cracks and wear, especially at stress points like around the bottom bracket (just like you would with any frame).


How do I get rid of weird rubbing noise on my cx bike?

What has probably happened is that when you used the brakes the wheel shifted slightly in the dropouts. The disk brake pads run really close to the rotor, so even a tiny shift can be enough to cause this problem. The solution is to open the front QR lever with the bike upright. As you do that you will probably hear a little "clink" as the wheel settle back into the dropouts. Then tighten the adjustment knob on the other end of the QR axle before closing the lever. More detail here and here with diagrams (and even an animated gif!) or in even more detail at Sheldon Brown's site

The design problem that causes this is serious, and is discussed by people like John Allen and my view is somewhat more forceful than his but otherwise compatible.

You can download the manual for your brakes from the Tektro site and use a 5mm allen key to adjust the fixed pad (the one closest to the spokes) and the barrel adjuster on the brake cable to adjust the other pad.

There are a few descriptions of how to adjust the brakes on this site like this one and on sites like Park Tool (who like to shuffle things round so that link will be broken in a few months)


New Shimano 105 hydraulic brake loses pressure

Unfortunately, bleeding it is the first thing to try.

It's common for new bikes out of the box with hydraulics to require bleeding. Shops do it frequently during assembly, or good ones do at least. Factories don't do it consistently perfectly. There are a bunch of possible reasons, mostly boiling down to time.

Shops handle a lot of bikes and have their own time pressures. Letting a new brake through that needs a bleed is an easy mistake. That rear hydraulic STIs veer towards a long and not-the-firmest lever stroke anyway doesn't help.

Checking torque on the hose fittings at each end is also prudent, but probably not the problem.

The STI bleeding procedure has some steps involving lever positioning that need to be followed to do an exhaustive job. It's not difficult but it is different from MTB systems. Hopefully you'll be able to get it done under warranty by a judicious mechanic. If not I recommend following the procedure exactly for your brake from the dealer manual you can find at si.shimano.com.

Defective ceramic pistons are hopefully not the problem, but they do happen with the Shimano road hydros. If pad/piston movement doesn't seem right after bleeding, that's the next thing to investigate. The telling symptom for issues with them is stubborn or inconsistent piston movement combined with a crunchy feeling when resetting the piston. There are questions here about this.


If I'm riding on the road, and there is a red light but a walk signal in my direction, should I go?

Only cross if you are walking and pushing your bike.  If you are riding, you are a vehicle and generally you are required to obey all traffic control devices in the same way any other vehicle operator is. There are exceptions, like the Idaho Yield laws, but generally you have to behave like a car.

The other thing to think about is that the more you behave like a vehicle, the more predictable you are, and the more predictable the behavior of other vehicle operators will be.


I took a pretty quick look at the map, but I'm going to make a kind of general suggestion: If this is a trip that you're only used to traveling by motor vehicle, you might fall into the trap of thinking that the route you're used to is the only route available. Bikes can go lots of places that cars can't, and lots of places that cars just as frequently don't.

If you're just starting out, I would suggest avoiding the highway; it will just be really un-fun and discouraging. What I might suggest is that you start taking your bike out in the evenings, and start looking for other possible routes. You could even do some of this on your drive home.

The heat and the lack of shower space is something that really depends on your comfort. You should be able to avoid the heat of the day, and you won't be out long enough to really worry about dehydration, but you might want to at least change your shirt when you get to the office, and have a towel or something to wipe yourself down.


Does a Sturmey Archer 2 speed kick shift hub let you backpedal?

The original Sturmey-Archer 2 speed kick-back hubs are coaster brake hubs and do not allow much movement backwards before the braking happens.  Track standing on a coaster brake would be tricky because the pedal position would always rotate in the direction of travel and you would eventually end up at the dreaded 12 o'clock position.

The new versions have two models;

◎ Type S2 2-speed freewheel hub ,without brake
◎ Type S2C, B2C 2-speed hubs ,with coaster brake.


Will dual pivot caliper brakes work on cantilever fork?

You need fork with approximately the same axle to crown length (i.e. the fork legs are the same length as your current fork), with a proper brake mounting hole at the top of the forks. The hole in the forks in the picture is for mounting mudguards or fenders and is not suitable for mounting a caliper brake.


I would cut a bit of 10mm or 12mm plywood to fit underneath of the main frame section and use cable ties to hold it onto the frame. Probably at the level of that bar across the back of the trailer.  That gives you a lip around the platform as well as a very slightly lower centre of gravity. Having lots of cut-outs where things are attached to the button of the frame isn't too much of a problem.

Ideally you'd find a plastic bin that exactly fit into the space but that's very unlikely to be possible. You will most likely find that the bin you get either sits too low and scrapes on the ground, or is too small on one side to work properly. If you go this route I suggest getting one the right width to sit on the main frame members and not worrying too much about how long it is. Having two bins next to each other might also work.

I think keeping the cloth cover will be handy, it will help keep your load in place as well as giving you some shelter from light rain.

Be aware that kiddy trailer load ratings are not the same as cargo trailer load ratings. No-one is expected to add exactly the load rating of children (look, it holds 2.3 children!), and people tend to be more gentle with children than with cargo. So a 30kg cargo trailer will probably hold the same weight as a 50kg rated kiddie trailer before it starts falling apart.

The reason they cost so much is that people won't buy a cheap, heavy, solid trailer. Instead they buy cheap, light, flimsy trailers and wonder why they fall apart. I built 12 of the heavy style and it took more than a year to sell them even though they cost the same as the flimsy junk ones. That as an educational experience for me.


Why is part of this Derailleur loose? (Sun Tour Cyclone II)

It is hard to give you the exact reasons why this is happening, but your derailleur body lost a good mechanic connection with the cage. Maybe the screw that holds them has just became loose, or maybe it has gone bad, or maybe your derailleur is just old. Hard to tell from the pictures.
I don't want to be pessimistic, but repair will be hard, as manuals and parts are hard to find, and I suspect even if you successfully do it there will still be too much slack for this part to perform adequately.
It sure doesn't hurt to try. The only link I can point you to is for an overhaul of a Shimano derailleur, here. These components aren't too different and this should give you a help.
In the meanwhile, I would start putting some money on the side for a new one, the good news are that if you can't fix yours you can get something really cheap. If you ride a lot, it is better to invest in something a little bit better.
Good luck!


Can a carrera valor mountain bike be converted to disk brakes?

Assuming this is your bike, the answer would be no.  You could technically add disk brakes on the front, but it would require changing the forks to ones that had attachment points for disk brakes. You would also have to change the wheels/hubs to ones that are compatible for mounting the disk.  There is no good method of adding disk brakes to the rear as this frame is aluminum and adding disk brake mounting points after the fact isn't a good idea.

Why do you feel that you need disk brakes? V-Brakes can perform quite well if they are adjusted right and are good quality. A good set of v-brakes will work better than a cheap set of disk brakes.


To answer your specific BMX Bike
The King Gap XL 2021 will support pegs. It's safe to say that any freestyle BMX bike will support pegs. If you were buying a BMX race bike, there's a chance it doesn't support pegs; BMX race is more focused on being lightweight than freestyle BMX.
Can I put pegs on any bike
No, you need to have a certain type of axle to put on pegs. It won't work on a dirt jumper / mountain bike / road bike for example. The axle needs to stick out from the fork / dropouts to have room to house the peg. There's a nut that screws onto the outside of the peg, so if the axle doesn't have the thread, it won't work.

Now compare that to a MTB axle - this is a 15 x 110 boost axle, which is super common on MTB front wheels.

Words of advice
Buy plastic pegs so you don't ruin skatepark ledges


What are the strengths, weaknesses and/or recommendations for a BLB Mosquito Saddle?

Looking at the BLB Mosquito it is marketed as a "race" saddle which in the world of leather saddles seems to be short hand for narrow with the expectation that your cockpit setup has lots of handle bar drop (handle bars below saddle). Depending on the width of your sit bones, these saddles can be uncomfortable in a more upright position, as I have learned.

BLB Mosquito Race - side view

Brooks B15 Swallow

The BBL Mosquito also looks remarkably similar the Brooks B15 Swallow saddle.

As an owner of a B15 I can must advise you to carefully consider this saddle decision as it is really designed for race bikes. I am relatively average in stature and on the lighter side for weight.  I found this type of saddle was only comfortable in a racing position (i.e., 5-10 cm of drop on the handle bars).  Anything higher and my pelvis would rotate enough that the my sit bones would strike the metal rails.

Now everyone's anatomy is different, including sit bone width.  But for more general applications and for a more diverse array of body types, I think you should consider a wider saddle such as a Brooks B17.  Either that or measure the width of the BLB and compare it to the Brooks B17 to ensure the saddle is a bit wider.

As far as build quality, I haven't the foggiest about BLB!

Leather Saddle Caveat

Most seem to be drawn to leather saddles for their looks. I am so-so on the looks, and a much bigger proponent on the comfort, once you choose a model that is appropriate to the application.  This is where all the marketing speak has let us down.  The descriptions on  how the saddles can be expected to fit is basically non-existing.  This is unfortunate as the saddles can be quite uncomfortable for some application/body type combinations due to the fact the saddles work as a hammock and use a solid rail.

This is where modern saddles can be better as they can be expected to provide adequate comfort to a larger array of body sizes due to the use of padding. That said, once you get the kinks worked out, in 15+ years of competition and 20+ years of cycling, I have never found a more comfortable solution.


Contact a local club.

Most have regular training outings (weekends, evenings), you'll meet other racers who'll willingly teach you the tricks of the trades, the local routes and just the espirit de corps which makes competing all the better. (As well as recommending the best local events.)

Everyone was a beginner once, although not everyone remembers that. If there are no online chat rooms for clubs in your area it might just be worth going out cycling in the local area of a weekend morning and trying to see groups in similar kit and just asking people. Especially if you can find where they stop for tea!


Can mountain bike dirt remaining on different parts for long time damage the bike?

The main concern is water, and any other substance that might promote corrosion, such as road salt.

Leaving mud or dirt on the frame provides material for water to soak into. Even if you let it dry out it would held water for longer than it would take to evaporate otherwise, and can soak up more water later.

You obviously want to get grit and dirt off of your chain and sprockets as it sticks to the lubricant and promotes wear.

Bearings do have seals, so if you are careful with degreaser there should not be a problem  getting it into bearings and affecting the grease or other lubricant.

Update:

As brought up in comments there are areas that are more prone to damage through corrosion than others. Fork stanchions in particular.


Can anyone help me identify this bike from 2002?

This bike looks like my 1998 Specialized Stumpjumper based on color, setup and my guess that the logo behind your left leg is a Specialized S. That's the best I can given the blurry photo and the mud on the frame.


Need help with gears and wheel alignment

The rear spacing on most single speed frames is 120mm. The dropouts usually face backwards and can't take a derailleur very easily. Is your bike like this?
If so, a hub gear may be the best option. You can get a 2, 3, 5 or 8 speed hub gear that fits a 120mm rear end. This will maintain the clean look of a single speed, especially the 2-speed, that needs no extra cables.
If you try derailleur gears, you will need to create a hub setup that has enough space on one side for the sprockets/freewheel. You are unlikely to be able to do better than 5 gears, and mounting the derailleur will be a challenge unless you find an adaptor fit for purpose.


Replace my stock crankset and cassette for a 22-32-42t crankset and a 11-40t cassette on recumbent trike?

The issue here is going to be clearance between the frame and chain in the extreme gears. The smaller chainring moves the chain down towards the front crossmember, but from the images I've found online I don't think that will be a problem. The drop from 30T to 24T alone gives you a 19" bottom gear. In order for the rear derailleur to keep working you need to keep the gap between the biggest and smallest chainrings about the same, but you are planning on that anyway - right now 52-30=22T, you want 42-22=20T so that's fine.

At the back you have the issue that you need to clear the frame with the bigger cog, but you also have 10 extra teeth worth of chain involved. The jump where 11-30 becomes 11-40 might not work with your current derailleur, or might not allow you to use all possible gears. I suggest getting a 12-34 cassette instead, as the 11T cog wears out faster and the extra tooth will help you keep the rear derailleur happy. With 34T instead of 30T you get a slightly lower gear without going too far for the derailleur.

If you don't install extra chain, you probably won't be able to physically get into the 42-40 gear, and the drivetrain will wedge itself solid if you try. That can damage the trike, either snapping the rear derailleur off or bending it into the rear wheel.

But if you add the extra chain the opposite happens - in the 24-11 gear you have so much chain that the rear derailleur can't take it all, and you end up with chain dragging on the ground. If you run over the chain the rear wheel will stop and you'll slide along on the chain, wrecking a section of it.

Note that quite a few recumbent riders do this, because the gears where this is a problem are not really useful gears. It's generally better to have the extra chain, because you can shift back out of the bad gear and keep going, but if you wedge the drivetrain it can be annoying to fix even if you don't damage anything (often requiring you remove the rear wheel, or release the boom so you can slide it back and loosen the chain enough to free it).

You will also need a few tools do to this, specifically a chain breaker (and some extra chain links), a cassette removal tool, and some allen keys.

I suggest contacting Catrike first, as they will know exactly what you can do with the trike, and likely sell you the parts for about the same price as an online shop would. Then you can try taking the trike to a bike shop if you have one nearby, or start watching youtube videos showing people changing cranksets and cassettes. All the bike bits like gearing work the same on your trike as on a bike, they're just in different places. So all the instructions you'll find online should help, you just have to remember that "the bottom bracket" is actually out the front :)

Answers here like "is my chain too long" will give you ideas about how to work out the correct chain length after you've made changes. Some of the answers on "cross chaining" talk about why those gears don't matter (they duplicate other gears from different combinations of front and rear cogs).


Aside from getting a TT specific bike,

1) Get a new seatpost which allows for more saddle adjustment

2) Get a new saddle

are probably your options best options. I don't think the padding will help. When you added aero bars, you changed the riding geometry, and pretty much aside from swapping out stems/bars and tweaking heights there, your only other option is a new saddle and/or seatpost.

I don't think the padding is a good idea, given that you shouldn't be sitting on that part of the saddle anyway.


It's almost certainly going to be more cost effective to replace the whole bike, and selling the current one.

There are potential problems with both brake caliper and derailleur compatibility going to flat bar shifters.

Aside from replacing shifters, drivetrain and bar, drop bar road bikes have shorter frames than flat bar bikes, because the rider's hands are placed forward of the stem head on the drops or hoods, but a flat bar places them approximately level with stem head. You may find the seat to bar distance is too short with flat bar installed.


What large chainrings are compatible with Shimano FC6603 crankset?

The FC6603 seems to use a standard 130 mm BCD 52t chainring for the outer ring, unlike the special ones used on some other Ultegra/Dura-ace cranksets.

You can buy such rings from  most major brands. Look for ones marked 10 speed or 11 speed.


Brakes make sounds when:

Pads are worn out and metal plate of pads makes contact with the wheel.
Pads or wheels are dirty and greasy.
There is some loose part in braking mechanism.
Pads are rubbing against the wheel.
Overheating caused by long and hard braking.
Pads are wet.

To fix each of problems listed above do this :

Replace the pads.
Clean pads and wheels with some brake cleaner, degreaser or rubbing alcohol.
Tighten the loose part.
Straighten the wheel or align the pads.
Try to not brake if isn't necessary, or get better brakes that could handle the heat better.
If you are riding in wet conditions there is nothing you can do about it.


Buy second-hand bike in or near Frankfurt

I actually grew up near Bad Homburg, and have bought a used bike there. (You do realize that depending on where in Frankfurt you want to go, the way there from Bad Homburg can be quite far?) The two biggest bike shops there are Fahrrad Denfeld and Fahrrad Diehl. At least some years ago, both of these shops sold used bikes as well, and for reasonable prices. I think I bought one from Fahrrad Diehl for 150€ that I used during my 5 years of studying

Communicating in English should not be a problem in either Bad Homburg or Frankfurt, especially with people from "younger" generations / who are < 50 years old


Does a helmet-mounted light affect the safe functionality of the helmet?

I found something on the homepage of the Bicycle Helmet Safety Institute. They have an article about bicycle helmet lights, listing the pros and cons of them:

Summary: Lights on bicycle helmets can be useful, but must have a breakaway mount.

Especially about the breakaway mount:

The importance of breakaway mounts
The first and most important rule for mounting a light on your helmet is that it must break away readily when you crash or catch an overhanging obstacle. If it does not, you risk having your neck jerked when it snags on the pavement or tree. Besides jerking your neck, that can add to the g's of the shock to your brain when you hit pavement.

Although there are no studies mentioned how dangerous it is when the light does not fall off during a crash, some manufacturers test their lights to break away during a crash:

Only one helmet manufacturer we have spoken to provided their lab test levels, Uvex, proving that they actually have an internal standard. And the light manufacturer Jet Lites has a standard requiring their mount to break away when loaded with a 5 pound weight.

This shows that it is important that the light falls off during a crash, but unfortunately most manufacturers do not care. Which seems to be a problem:

Some manufacturers use hook-and-loop straps to hold their lights on. We have seen some that wrap through the vents and under that seemed unlikely to detach when they should have. But again, there is no standard for that.

Source: http://www.bhsi.org/helmetlights.htm


How is "correct" tire pressure related to tire volume?

If you ignore the strength in the tire walls (pretty much zero for bike tires) then the pressure (which = force / area ) multiplied by the contact area of the tire on the road must be the force you are putting on the road (ie. the weight of you and the bike).

So for a large tire contact patch you need a lower pressure to support your weight, for a small area narrow tire you need a much higher pressure


I suggest taking it back to the shop you got it from, as it looks like a manufacturing defect. Since the bubble isn't visible on the inside it's clear that the layers of cloth inside the tyre have separated, and that's not supposed to happen. You should be able to get a warranty replacement.

Sheldon Brown has an explanation of how the tyre is made that may help you picture what's going on: http://sheldonbrown.com/tires.html


Which parameters should I track with bicycle computer so I can analyze changes in my riding?

You will obviously be able to get this from your trackpoints, but it can be useful (depending on the frequency of collection of trackpoints) to take speed - directly from your front wheel tacho if possible. This just gives you a higher degree of accuracy.

Other nice to haves:

accelerometer input - both fore-and-aft, and left-and-right - these can give a good correlation between the movement of the bike and the cadence and gear readings so understand how the power is being transmitted to the road.


Rear derailleur noise in big/big combination

Drive trains with a front derailleur system are designed with to have overlapping gear ratios ranges for each front chain ring to allow you to spend most of your time riding with the chain not stretched to the extremes of your rear cassette.  Riding in your largest gear on both your front and rear is call Cross Chaining.  Cross Chaining puts unnecessary stress on your drive chain system by forcing your chain to work through extreme angles to propel your bike forward.

Additionally, you'll get a grinding noise when using the most extreme gear combinations as you are forcing your chain to go from front to extreme back.

Best best to avoid that sound is to practice shifting both your front and rear derailleur.  Starting out, it may feel awkward but your bike and ears will thank you ;-).

It is worth spending some money at the mechanic to give it a good inspection to make sure everything is in safe working condition as well.  Nothing is worse than having something break when you are riding.


I agree with Nathan Knutson's comment that this looks like cable friction, but I suspect confirmation bias has everyone looking at the wrong portion of the cable routing.

  The mechanic I spoke to said that this was a problem with the design of the Allant 7.4. The shifter cable comes out straight at the same angle from the chain stay. It gets bent upward and sits in contact with the quick release nut. The mechanic told me that the problem was due to the sharpness of the angle that the cable was routed after it exited the chain stay.

The rear derailleur cable routing isn't perfect, but it does not look that bad either. There is nothing inherently wrong with the cable housing touching something.  The problem can arise if the housing is severely kinked, which doesn't appear to be the case, I beleive the manager is correct in that this is likely not the culprit.

You also said:

  The shop I bought the bike from has replaced every single component involved in the rear gears (possibly not the external sheath at the back? The manager told me this couldn't be the cause of the problem). The cassette, derailleur, chain, shifters, shifter cable core (now using a thinner core) have all been replaced.

This still leaves a couple possibilities:

Cable housing from the shifter to the frame has a kink.  You made no mention of whether or not the cable housing (cable outer) was changed.  If the housing is a bit short and/or the handle bars get over rotated this can damage the housing.  This however should have been obvious from inspection, and I would hope a reputable shop would have looked here first, long before cassettes, derailleurs and shifters!
Inside the frame, you are missing a sheath or the cables inadvertently became entangled during assembly. If the cables are tangled, then this would cause extra friction. You might be able to see this by activating one shifter and looking for movement on the other derailleur. Friction could also be increased if an internal sheath is missing. Most internally routed systems will run the cable inside a sheath to reduce friction. If is missing, then the friction is higher.
The shop changed the inner cable, but depending on how this was done, they might have missed these type of problem (e.g., you pull the new inner cable through by using cable that is currently in place).

Typically, internal cable routing results in straighter cable runs and should provide better shifting for longer than external routing.


SRAM Twist Shifter Paired with Shimano Rear Derailleur

No, SRAM grip shifters will not work with a Shimano road derailleur.

The SRAM 11 speed grip shift units I found online use what SRAM calls x-Actuation which means a derailleur actuation ratio (length cable pulled to derailleur movement) of 1:1.12. Shimano 11 speed road uses 1:1.4.

Source for this info: https://www.artscyclery.com/science-behind-the-magic/science-behind-the-magic-drivetrain-compatibility/.

However, I think you probably have deeper compatibility issues that I should point out. If your bike is vintage then is will have narrower hub width than modern bikes, 120 or 126mm perhaps vs 130 or 135mm. An 11 speed cassette will not fit on a narrow hub which makes me think you actually have a lower speed bike. As the number of sprockets increases the spacing decreases, therefore you cannot use a 11 speed derailleur/shifter combination on a sprocket cluster with less than 11 sprockets, as the sprocket spacing will be wrong.

The basic rule of derailleur and shifter compatibility is the shifter speeds need to match the number of sprockets, and the derailleur needs to match the actuation ratio the shifter expects.


My front rotor seems to be making a grinding noise, I have a relatively new bike and I’m not sure what’s causing it

It could be that the brake caliper is not aligned properly. It is a simple procedure described in this video by park tool
How to Align a Hydraulic Disc Brake on a Bike


Is it ok to use a 9spd link on a 10spd chain?

The problem you might run into is too much movement in the link. This will not show any problems for a while, maybe months, but the more movement there is the more damage you are causing the link and it will eventually fail.

Depending on what you are doing at the time when it fails, you might just be inconvenienced and have to walk home or, in my case when I was 18, launch yourself over the bars at 25 MPH, slide down the road and open your elbow to the bone, spend 3 hours in the ER digging out all the gravel, have a wound that smells like rotting meat, and a scar that takes up 25% of your arm 20 years later... Swap out the link when you get a chance, or better yet, buy a new chain, WAY cheaper than an ER visit!


Tektro Brake will not extend pistons after bleed

You're bleeding them wrong.
Tektro has been making decent hydros, but the clarity of their published bleed procedures has still left a lot to be desired, so I don't blame you.
Their published instructions differ a little across models, but what I do for most of them is put a bleed block in, position them such that the port on the lever is the highest point and the port on the caliper is the lowest point, put a syringe on each end (starting with the new fluid in the caliper end), and push the fluid up while applying gentle back pressure on the lever syringe plunger. This is where you'll see most of your bubbles. Then if what came out is dirty, I remove and drain the lever syringe, replace it, refill the caliper syringe, and repeat until I'm getting clean looking fluid all the way through. Then I push it back and forth a few times, keeping the syringes upright to collect the air. You could bonk on the caliper and lever with a soft tool to loosen bubbles if you want, but I typically find it not necessary. When you're not getting any more bubbles in either direction, remove the syringe from the caliper end first and close the port tight, then the lever end. Once both ends are sealed, squeeze the lever with the bleed block still in, and it should be rock solid. I never actuate the brake lever before this with Tektros.
If you only have one syringe (the Tektro consumer kit only comes with one), I believe you do it by setting up a collection bag at the lever end and pushing fluid up from the caliper, but to be honest I never do it this way so I may be missing something.
No bike brakes today are bled without a bleed block in place between the pistons. You don't want the pistons able to move around during the bleed process because then the fluid will be overfilled and your pad gaps will be all screwed up. You can improvise one by cramming whatever in there and holding it in with tape or a rubber band. Or, in most cases a Shimano block of the same pad type will go right in too.
Actuating the lever like you're doing in the video with the caliper bleed port still open is going to cause the exact behavior you're seeing of shooting fluid out of the bleed port without moving the pistons. The pistons have some resistance to overcome from the seals etc, but the fluid will move freely. There's not really a circumstance I can think of where it makes sense to squeeze the lever with the caliper bleed port open.


This is the tool you're looking for:

https://www.ebicycles.com/bicycle-tools/frame-sizer/bmx-bike

It's not a linear calculation, but it would be fair to say that a rough estimate is: start with a 22.5" top tube for a 6' adult male, and add/subtract half an inch of top tube for every inch of height.


How to install a chain that has a pre-fitted pin?

Shimano 11 speed (5800) should be assembled with a Shimano chain connector pin. The pin is pushed through and the end breaks off.  9/10/11 speed chains outer plates are too narrow to reuse pins.  There is literally no margin for error.  You actually break part of the pin when you push it out, as such it won't stay in place if reinserted. A missed shift can easily pry the outer plate off the pin causing the chain to fail.

I suspect you were sold a used or pre-installed chain, where they pushed the pin partially as a "service" to you, but if you reinsert that pin in all likelihood the chain will fail at some point in the future.

Shimano chain connector pin

UPDATE

The online retailer (guessing chainreaction) may also be selling an OEM (Original Equipment Manufacturer) chain:

  CRC supply OEM chains which have a short rivet pin partially inserted ready for use. Never had a problem since I learnt how to use this rivet. You have to be careful that you get it in the right position first time when using your chain tool, as there is no room for error, when compared to the long pin type of rivet. If you try to adjust the chain pin it soon comes loose.
  It isn't just a removed pin, as these are always too loose to use, as part of the rivet shoulder breaks away during removal.
  Mind you it's always handy to have another way of joining the chain if you don't get the pin right first time.
  I find that you have to just take your time when pushing the pin through the last bit to avoid going too far through.
  -- Forum Thread

I have never personally had access to OEM (equipment purchased by bicycle manufacturers) so I cannot confirm whether or not this is how the chains come.  Either way, the forum thread suggests assembling with these short pins can be difficult (other answers discuss how to do this).  You may wish to purchase a connector pin as this is how Shimano intends home mechanics to assemble chains.

To clarify this short pin may not be the same as a pin that has been pushed out on an assembled chain. But it is hard to verify what the OP has.


What is this crank and BB on this bike? And how do I take that sort of crank off?

The bottom bracket is a external bearing type in a threaded bottom bracket shell. I think it's likely a FSA Mega Exo as it's paired with a FSA crank, but could possibly be Shimano Hollowtech II.

You have removed the bearing pre-load cap, which does not retain the crank. To get the rank off undo the pinch bolts. On Shimano cranks there is a little tab of metal in the slot that fits into a groove in the axle. This needs to be removed to slide the crank off. Not sure if FSA cranks have the same feature.

The crank will probably be quite hard to get off the axle, a few tabs with a mallet may be needed.


I have never had experience with an RS Revelation fork, but you might find this forum post useful. Common solutions seem to be taking the fork apart, cleaning, and re-oiling the o-rings. Good luck!


Does one replacement automatically require another?

The short answer is no, it shouldn't. Only if it's worn out too.

With regular cleaning of the drivetrain 1 cassette usually lasts 3 chains and 1 chainring usually lasts 2-3 cassettes, assuming you replace the chain before it's too late.

Bottom brackets have no direct relation in terms of wear to the above components, but it rather depends on the following factors: quality, weather conditions, how often was it powerwashed, the terrain you ride on, your pedalling style and if it's a serviceable unit, then how often was it serviced.
A Shimano Hollowtech BB should last between 10 to 20 thousand kilometres.

Signs of a worn BB: The crankset is properly installed, but it's still loose. Clicking sound with each pedal stroke. Roughness when turning the cranks.

My personal advice: If you're worried about the BB being worn, but it doesn't have any signs, order a new one and store it in the closet until the old needs replacing. It should be an easy job to replace ( if you have the tools, otherwise take it to your LBS) and there's no need to do it together with the crankset.( Removing the crankset is 1-5 minutes, so it won't add that much extra work, but you save money and help the environment.)


First thing to check for is sharp foreign objects embedded in the tire that poke through to the inside. These can be small enough or not protrude enough to be invisible, but can poke a small hole in the tube over time.
As this has become a chronic problem I'd thoroughly inspect the insides of your tires. Remove tires from the rims and turn them inside out. Use bright light and run your fingertips along the interior surface feeling for small sharp objects in the rubber. Run your fingers both directions to catch objects embedded at an angle.


Where to find a 14.4 mm long and 16.9 mm wide hub cone?

If you visit your local bike shops, there is a slim chance to fund a replacement. On the other hand, the most reliable and time-efficient solution is to replace the whole axle. In my region, the options are an Weldette unit for about 7.5 EUR or a M-Wave axle for about 2.5 EUR. Do ask around.


Cycling on the sidewalk/pavement fines in belgium/netherlands

Fines in the Netherlands for the two most instances of wrong "place on the road" most likely to apply, are at the moment € 55,- although there's always article 5, which says you shouldn't endanger others on the road.

I couldn't find any definitive data on Belgium.


When wearing a helmet (and you're in Australia, so I assume you are) I almost always use an undercap, be it a classic styled cycling casquette, a skull cap or, in winter, a thicker beanie, perhaps with ear protection.

In summer a casquette works well because I find that the sweat does form on the peak, but can then either drip off or evaporate more easily.


What to use to clean your chain (and cogs)?

A degreaser, whether aerosol or not, is an excellent way to remove grease from the chain.

http://www.finishlineusa.com/products/citrus-cleaner.htm

http://www.finishlineusa.com/products/speed-clean.htm

The degreaser will reduce the amount of elbow grease required but be careful and use a set of nitrile gloves to protect your hands.

My simple chain cleaning method is as follows:

Shift into the big ring and little cog, wet the rag with the degreaser

Grip the chain (lower portion, going from big ring to the derailleur) with the rag, focusing on holding firmly onto the outer plates.

Turn the crank putting the chain through the rag. Readjust as necessary as you remove grease and grime from the chain (ie. don't keep rewiping schmutz back onto the chain).

When sufficiently clean, remove the rear wheel from the bike and place it between yourself and a wall (ie. tyre against your stomach/tyre against the wall keeping the wheel propped between yourself and the wall) over a garbage can.

Using a thin screwdriver or a cleaning tool ( http://www.parktool.com/products/detail.asp?cat=4&item=GSC-1 ) clean the grass and grease build up from between the cogs of the cassette/freewheel. Lightly apply degreaser to the brush portion of the tool and scrub at the cogs to free up the grease/grime.

Using a rag, with degreaser on it, insert the edge of the rag between the cogs and 'saw' back and forth with your hands thus spinning the cassette and fully wiping the whole cog. I typically move from top to bottom of the cassette (keep the grime flowing downwards).

Wipe down cassette, hub and any spokes/rim that could have been contaminated. Reinstall the wheel in the bike and one last time wipe down the chain with the degreaser rag.

And typically ... that method suffices for cleaning any of my bikes. The one caveat is that I typically don't let the chain get grease/grime covered and thus this takes about 3-5 minutes max and works really well. The worse your chain, the more you have to do.

You might want to look at your derailleur pulley wheels and using a flat edge against the pulleys as you spin the crank, remove the grease rings from the pulleys.

You might want to pre scrub the chain (similar to how you did the cassette) to loosen the grease/grime on the chain. A tooth brush w/ degreaser or the GSC-1 mentioned above would be sufficient.

Andddd... that's about all I've got for now. There are a plethora of other methods using chain cleaning tools, removal and soaking of the chain and nastier solvents but for the majority this method seems to work fairly well.


My rear disk brake doesn't lock in place. Don't know whether hydraulic or mechanical

You mention the brake is brand new.

Have you "bedded" the pads in?
Bedding involves riding down a hill and feathering the brake lightly.

The other possibility is pad / disc contamination. In particular oil.
Discs can be cleaned with appropriate solvent.
Pads can be cleaned by baking (faced down) on grease proof paper or gently heating over a flame to burn off the residue.


I live in a place where it frequently floods. How can I keep my chain from rusting?

If you're getting knee-deep floods it's destroying the bearings along with the chain.  You need to hang the bike up somehow.


Riding from San Francisco to Los Angeles

Assuming you're riding the Pacific Coast route, North-to-South is clearly the favorite over South-to-North, at least among Crazy Guy on a Bike users. I'm not sure why that is. I'd recommend reading some of those tour diaries to see if they explain the reason.


Is it normal that I find it hard to skid?

I assume that by "riding fixie" you also mean "riding brakeless", or at least trying to master stopping without using brakes, only using your legs and modulating your weight. Changing the gearing is also a way to make it easier or possible, as I will try to show below.

To make any wheel skip, the friction between a tire and ground must exceed a critical value for friction force Fgliding. Below that value, friction force is defined by equation F = µN, where µ is a constant coefficient depending on the surfaces in contact, and N is reaction force, which is equal to the weight loading that wheel.

Under the drivetrain braking, the deceleration force (== tire/ground friction) will be equal to the force your legs apply to pedals multiplied to a constant. This constant is defined by your front and rear teeth count, cranks length and wheel radius. Basically your drivetrain is a lever, to which you apply one force at one end and get a transformed force value at another end. You cannot load your pedals more than you weight (more or less). Thus, your legs and body can create a limited amount of equivalent stopping force at the rear wheel, let's say Flegs.

If Flegs < Fgliding, you will be unable to skid. You'll still be decelerating, but the rear wheel will be turning while rolling (not sliding) over the ground. Because it is a fixie, pedals will also be turning "against your will", forcing your legs to obey their rotation.

To make it skid, you'll need to either 1) increase Flegs, or 2) decrease Fgliding. To affect the former value, gain weight or change your gearing combination. To affect the latter, you can either reduce µ, which is exactly what happens in the rain, or reduce N by unloading your rear wheel.

To illustrate it a bit differently, if you throw your rear wheel just high enough so that it does not contact the ground at all (N= 0), your will be easily able to stop its rotation with legs while it is in the air: a wheel's inertia is obviously less than that of the whole bicycle + yourself. When the wheel lands back to earth (N > 0), it will be stationary (relatively to the frame), while the ground at the contact point will be moving relatively to it (because the whole bike has not yet stopped). This non-zero relative speed between the ground and the wheel's contact point is the definition of skidding: instead of rolling, the wheel slides. The re-obtained non-zero friction will cause the wheel to gradually start gaining its rotational momentum again; but that cannot happen instantaneously. It will continue skidding until the speed of its contact point becomes zero, at which point it has again regained its full rolling contact and speed.

This is exactly what happens when braking a mountain bike over an uneven terrain. The bike "flies" for short moments from root to root, stone to stone. Wheels' rotation, while in air, is halted/slowed down by applied brakes. Upon landing wheels produce this "skrrt-skrrt" sound of spinning back while skidding for short periods.

Given that there is a small negative gap between values of rolling and sliding frictions, this state of the wheel gliding can be made "stable", not temporary. If you find a sweet spot where the rear wheel is loaded just enough so that Flegs = µN, you will be able to skid continuously until a full stop.

Sheldon Brown describes the same physics behind the process, while giving a bit of details on how to place your body and pedals to unweight the wheel: https://www.sheldonbrown.com/fixed.html#skip . Pay special attention to health warnings he gives about doing it on that page: "Heavy-duty resisting is widely reputed to be bad for your legs, and to be counterproductive for building up muscles and coordination for forward pedaling."


I feel long rides exclusively in my quads, should my calf muscles be doing more work?

I don't think you have a problem here. Physiologically, your thighs are the engine room of your legs. They are designed for endurance and power and can keep working at a high output for extended periods of time.

Your calves are more for short bursts of power, such as jumping or sprinting. They can't sustain high power output for any length of time. In distance cycling, your calves should be fairly passive. Attempting to work them harder will probably just result in fatigue and injuries.


Shimano Dura Ace FC7900 crankset with 11 speed group?

The FC7900 crankset is from a 10 speed group.

Nobody's going to stop you from doing this and having it work -- Zinn has done it and claims that it works. Manufacturers will will say otherwise claiming weaker FD springs or very slightly different chainring spacing.

Since you already have the crankset, may as well put it in and try it if you want to use it.


why do my pedals keep turning when i freewheel?

The friction between the bearings, pawls and lubricant in a freehub or freewheel are usually enough to turn the pedals when the wheel is spinning. If you hold onto the pedal and the wheel freewheels normally, probably there isn't anything to worry about.

Of course, if the wheel stops freewheeling altogether or the friction to resist the wheels turning becomes noticeable, then inspect the freehub bearings and pawls. Increased resistance at the freehub/freewheel will often result in the rear derailleur being pulled completely taut when the pedals are stopped.


Rim tape doesn't quite meet, but covers all spoke holes - OK?

This is usually ok. as long as it has strong enough adhesive to stay in place. It's better to overlap it, of course, but as long as the spoke holes are covered it should be ok.

A bigger issue is that usually, when the tape comes up short, it means that roll was designed for a 26" wheel, and is going on a 700c rim. If that is the case, make sure the tape is not too wide, because if it is, it prevents the bead of the tire from seating, by filling some of the space in the beadlock on the rim.

If it curls up on to the side walls of the rim at all, that is not a good option. There are different widths for 26" tape, so even if it is 26", it can still be the correct width.


Trouble Removing bottom bracket. Is it my Tool?

Assuming you've got the right direction you're turning and its still not budging, use some penetrating oil and/or  borrow a breaker bar/vise (and use it carefully).

One of the things with your style of tool vs the park tool style of tool is that you can't get as much torque on.

In the case of aluminium, its conceivable that theres some corrosion, but dissolving it or heating it might be tricky depending on other types of materials involved.


How can you recognize a department store bike?

As per @Mikes Answer, but a bit more than fits into a comment.

Only buy a bike with the brand/model of major components able to  be researched.

On a Mountain bike, shocks are a dead giveaway, and if rear suspension, look at the shock, although they sometimes don't have a model, the good ones always have a brand. From there, pictures will get you close enough. Also look at the geometry - if it looks like a light weight motorbike it's rubbish (Unless it's a top end down hill rig)....  keep in mind age makes a big difference here, so search teh internet for parts of similar ages.

Brakes - Disk brakes should have a brand/model than can be researched. Rim brakes usually have something, but it's always a bad sign if not.

Seat / Seat post - worth a look, not a bad sign if no brand.

Drive train components can be tricky, many shops put an expensive rear derailleur on an otherwise cheap bike (That is all many people look at). Look at the cranks, the front derailleur, the shifters etc. These will usually have model information somewhere.  Wheels and hubs - again look at the brand/model - most came out with labels.

One useful guide is overall weight - lighter bikes cost a lot more. BUT make sure you compare like for like. No point comparing a carbon frame to a steel frame and assuming the carbon is better because it's lighter.

For a novice stick to a brand/model that you can get the details off the internet. Look for a bike that has signs of light or no use. Everything should work smoothly and reliably. No groans, squeaks, clattering of any sort. The problem is any of these can be a sign of big money or a 2 minute tweak to fix and it takes expert eye to tell the difference.


Should I remove foreign objects from my tyres if I'm running tubeless?

In general, I would recommend removing thorns and other debris even if the sealant is holding. Tubeless sealant is typically latex based and designed to adhere to rubber, not glass or wood fibers. As mentioned in The Benefits of Going Tubeless the sealant could fail to seal around a foreign object and leak air until it is removed. While not immediately obvious a poor seal could allow a slow leak which will require reinflating the tyre more frequently. The usual argument against removing thorns is that you will be reopening the puncture and losing air as the sealant plugs the hole again, however given you are free to do this at your leisure you should be able to reinflate the tyre at the same time.

The major reason to remove foreign objects instead of letting them build up is in case you get a puncture so severe you need to use a tube. As DWGKNZ mentions in their answer to How do you fix a puncture on tubeless tires? if you leave thorns in the tyre you will need to remove them anyway when putting a tube in and it'd certainly be more comfortable to remove the majority at home instead of on the side of a trail.


All Shimano chains I've fitted recently have come with a special connecting pin in the box, rather than a pre-fitted flat pin.

This dealers' manual for Shimano 11 speed chains only describes use of the bullet-shaped connecting pins: https://si.shimano.com/pdfs/dm/DM-CN0001-02-A-ENG.pdf

You can buy packs of 3 or more. Fit one then to avoid long walks, keep the others in your wallet or in your puncture repair kit.


That is the seam where the two edges of the rim were jointed.  Cracks, as you have noted, do not form in such a perfectly uniform way.
As long as the edges remain closely butted together as they currently are, you are good to go.


I slightly wrecked my bike - looking for parts - how do I start?

Before you start, check very closely at the top and down tubes, about 1-2 inches behind the head tube welds.

Your frame may be damaged in these spots, which is totally counter-intuitive.  A steel bike will develop two rust rings here after a front-end collision.

Use a magnifying glass or a jewellers loupe, and a bright light to look for any cracks or distortions.  A metal ruler can be used as a straight-edge to look for sharper bends.

Spending money on forks may be wasted if the frame is damaged.

That said - I rode a steel bike that had frontal damage for several months.  You need to make a judgement call once your inspection is done.

Can't build a house on a poor foundation; can't build a bike on a damaged frame.


No! Don't do it!

Certainly not with aluminium / alloy bars. Any bending stresses the internal structure of the metal, weakening it. Even in a metalworking shop, I would be doubtful of the safety of the product. I hesitated to say final product because the result could be ... final. For you.

Even with steel bars, I wouldn't do it. With steel bars we used to bend them slightly to have our preferred shape. But the wall thickness of steel bars these days is so low that I would not recommend even slight bending. With such low wall thickness almost no amount annealing or other treatment will restore full strength.

The other thing you mention is using plain pipe. Since it's not high-tensile steel (it'll be plain carbon steel), to be strong enough it will have thick walls and be heavy.


How do you deal with flats in the winter?

Prevention (good tyres, good inflation, regular checks).

For most rides, walking isn't an option, while I do sometimes run my commute, I use the bike because generally I want to get home. So a spare tube and CO2 is obligatory - with practice and a decent place to work (which can't always be guaranteed at the side of the road) I can change a tyre in less than five minutes.

In colder weather (at or around freezing) I ride with thin liner gloves inside cold weather gloves and I find I can change a tyre with them still on; this both keeps the fingers slightly less cold, but also a little cleaner.

If you're operating in a climate that regularly sees weather that's cold enough that five minutes without gloves is not an option, chapeau. But I think I would be looking for run-flat options (e.g. goo) and some way to get me home quicker than on foot!


Busted my bike hub & derailleur (I think) - how bad is it?

Updated based on your edits and comments.

The severed piece of metal circled in the 3rd image is one of the cage plates, and was originally attached to the lower (idler) pulley bolt.  Beyond replacing the derailleur, there is no additional damage there.  It really does appear that you may only need to replace your derailleur (and chain).

Other items to check out, at least to verify that nothing else is broken:

If you can spin the wheel and it rotates cleanly on the axle and is straight and the spokes are unbroken, straight, and under even tension then the wheel is good. (If some of the spokes are deeply scored you may want to replace them anyway.)
If the freewheel spins cleanly, and there are no bent teeth or wobble then it is okay.  (Though if you're replacing the chain it may need replacing anyway depending on wear.)  Based on the way the derailleur bent it's not likely it damaged the freewheel, but it's still worth checking.
If the frame itself is not bent (the distance between the dropouts hasn't changed, they are still evenly vertical and level with one another, and the stays are all straight) then it's fine.  (If it's a steel bike then a small amount of bending is survivable, but if it's aluminium it's trash.)
Obviously the derailleur is trash, but the derailleur hanger might be too.  (It's hard to tell from looking at the back side like this.)  You'll probably want the shop to make sure it's not twisted, which would cause the derailleur to mis-align.
You need a new chain, no question, since it sounds like a jammed link is part of the sequence that caused this.


According to Slowtwitch Shimano needs one junction A in the system otherwise it won't work.

You can skip junction B.

It may cause some interesting wiring.

The 6700 series (EW6770) junction may make things smaller/easier.

This is the same answer for all current e-tube di2 systems. (6700,6800,9000)


Bumpy ride. Is it the casing or the inner tube?

OP said:

  Well I still had a warranty on my wheels so I've changed them. They
  stopped being true I think. When rolled at high speed the wheel
  (without tubbing and tire) was very unstable.

Hooray for warranties!  Remember, always keep your receipts, and don't procrastinate or the warranty window may close on you.


When shifting both left and right shifters, what's the preferred sequence?

It doesn't really work to ask or answer this question independent of rear cluster gear count, range, and chainring tooth difference. In particular, road compact vs standard front gap leads to totally different strategies with shifting.

The more gears in back for a given cluster range, the less downside there is to just staying in the same chainring chosen based on the terrain you're in. The technically most optimal gear may still be on another ring, but there are efficiency and enjoyment downsides to doing all that back and forth shifting to stay on top of it. This effect has increased marginally with each speed generation.

The greater the chainring gap, the more rear shifting you need to do if you insist on sequencing your gearing exactly. That's a big reason why compact really took off in the days of 10 speed and not 5 speed - with 5 speed rear ends you're priced in to doing that sequencing, but with 10 it matters a lot less.

Also the greater the ring gap, the more gear values you're going to have back to back on the same ring at the extremes of the bike's gear range. For example, on 11-speed 34-50 11-25, the top 6 or so gears are all on the large ring and the bottom 4 or so are all on the small, so there's going to be a lot of the time where the most optimal sequencing involves no front shifting at all. Compare that to five-speed 42-52 13-25, where the only the top 1 or 2 and bottom 1 or 2 gears are on their respective chainrings. Again, you're then priced in to hunting around.

If you want to master this topic, studying different setups in a gearing calculator like https://www.sheldonbrown.com/gear-calc.html is a good idea.


Climbing or aero bike for a light rider?

Generally, being light weight you probably have more of a deficit on the flats, which would point to an aero bike. That is your frontal area per watt per kg will be higher than a larger rider who is heavier, can turn out more watts and has a bigger frontal area but also has a  a relatively lower frontal area per watt per kg.  As such, an aero bike would addresses your main deficit, would likely provide a bigger overall gain.  Delving further into the details we can again see that an aero bike will likely provide the biggest gain in most situations.

GCN (who's test riders were former pros - i.e., spindly and light weight) tested a  scenario very similar to what you are asking. They compared a "climbing" to an "aero" bike over a time trial with a mix of climbing and flats.  They found an edge to the aero bike by about ~1.5%.

  Caveat: The results of course lack replication and are subject to confounding variables (e.g., potential weather differences, psychological effects due to the study not being double blind). The effect size may also depend on the brand of bike as not all "aero" bikes are equally aero.

One thing that was not tested in the video was simply putting on a set of deep section wheels on the climbing bike to see how much of the difference was simply wheels.  There are plenty of videos showing there are sizable gains to be had, for example GCN playing with Zipp 808s (embedded below). This again points towards aerodymanic gains being potentially more important.

A nice feature of the test is that it nicely illustrates the impact reducing your workload (e.g., drag ) can have on human threshold performance.  With the more aerodynamic wheels Simon could maintain the same pace (i.e., speed) as non-aero wheels, but a lower total power output. The lower power output meant he could complete the workload (i.e., fixed velocity of 41.12 kph) for a longer period.

Humans are lousy machines.  Our ability to do a maximal work decreases over time (e.g., maximal power for 50 minutes is less than maximal work possible over 20 minutes). Our ability to do maximal effort falls off exponentially relative to duration. Below is a figure that illustrates this concept (Figure 1). The theoretical maximal power (i.e., maximal performance) is expected to drop with extended duration. The critical power (CP) is the maximal power that can be produced indefinitely and is much lower than what can be done over a shorter time interval.

Figure 1. Theoretical maximal power output by length of time the power can be sustained.  From Golden Cheetah.

This gets us the crux of why an aero bike will likely lead to bigger gains. Any time you can reduce the workload (e.g., decreased drag) you can increase the amount of time you can sustain a given speed. At threshold, an increase your workload (e.g., increased drag) shortens the duration over which you can functionally complete that workload (i.e., shorter period you can maintain a given speed).  Because races are at threshold, this has important consequences.

Now the question remains, which is a bigger workload, fighting aerodynamic drag or the extra work required to pull more weight up a given grade.  I would argue that drag will often be the biggest component. As you can see as soon as you start to go faster (i.e., racing time trials) aerodynamics becomes a larger component of your total workload if we ignore gradients (Figure 2).

Figure 2. Proportion of total power used to overcome rolling resistance and aerodynamic drag over a range of speeds. From R. Chung: At what speed does Aerodynamics of a bike come into play?

Next we need to assess the gains of a lighter bike on a climb. If we compare the difference in weight between a climbing bike and an aero bike, the differences is relatively small compared to your total weight. Probably at most the weight of a water bottle (lets argue a 1 kg difference). Using Bike Calculator, assuming you are  light (i.e., 60 kg) a 1 kg difference in the bike weights would require a sustained grade over 10 degrees to see a difference close to 1.5%  in velocity (see Figure 3). This means you need long, steep, sustained gradients to generate the performance difference observed in the first GCN video. Few if any time trials are structured like this, which implies a climbing bike is actually a highly, highly specialized tool.  You can verify this in the field by doing test time trial with and without a water bottle to estimate the effect this weight has on your realized performance.

Figure 3. Difference in speed between a climbing and aero bike for a 60 kg rider and a bicycle weight difference of 1 kg. Bike Calculator was used for the calculations.

Finally, I believe psychology also plays a huge role.  If a bike feels better to ride you will often perform better on it because of psychological like effects.  In fact there is more and more emerging evidence that perception plays a huge role in realized fatigue and therefore performance in endurance sports (see Fatigue Induced by Physical and Mental Exertion Increases Perception of Effort and Impairs Subsequent Endurance Performance).  If the bike doesn't "feel" good, you have to concentrate more and this can negatively impact performance. This could go either way in terms of aero vs climbing bike.


Your freewheel seems busted from what you say, it happens when the cogs are worn, nothing much to do there.

Everything is reparable but it sometimes takes a lot of time for not a lot of gain. Question is what is the value of your wheelcircle and from picture i'd say that's and old aluminium one. I don't know how that is where you live but in my neighborhood you can get a "brand new" used one for under 5 bucks. If the freewheel is busted you have to replace the entire bearing, meaning you have to take the entire wheel apart and then do the spoking from scratch. If you have a bit of experience and tools that is a good 1-2 hours of work, if it's your fist time count merely your sunday afternoon on it.

So my conclusion is : get a new wheel and recycle this one into an artistic project of some sort :)


Many of the expedition/endurance race fat bikes will come with rack mounts.  If you plan on "packratting" and carrying groceries, you should avoid the seatpost only options.  They generally have low weight restrictions and can also have issues with the bags flopping into your wheels (they are often missing the side panels regular pannier racks have).

If you look around a bit more, it should be fairly easy to find fat bike companies making rigs that are rack ready.  At most of the winter endurance races, racks and sometimes panniers are common.  The Surly Pugsley (the original production fatbike) still comes with rack mounts (rear AND front).


Can you identify this freehub from a 2014 Boardman CX Comp?

I made a guess. it turned out correct:
Trek/Bontrager (Select) Freehub Body 561948 (repl W268886)
Available from Pedalon (where I ordered from) or GB Cycles (from whose catalogue I figured it out).
GB Cycles listed a few similar alternatives but they can be discounted:

561949 is 11-speed (although worryingly listed a 130mm OLD, whereas my bike is 135mm OLD - but there are no sizes on the 561948)
W268886 has been superseded by the 561948
W211339 has sealed cartridge bearings

I'm still waiting for Boardman to come up with an actual part number or Halfords reference, although it's a moot point now.
I've only actually done a quick test fitting tonight, but the freehub fits the existing hub and the cassette fits on the freehub, so I think I'm good.
Not a direct answer, but I called up Boardman. Not entirely surprised they didn't have a part number, but they were able to offer up a reference with which I could order from Halfords. They have me the usual runaround, but hopefully should have something that fits middle of next week. In the meantime I guess I'll continue getting fat.

Boardman's reference on Halford's system: 341740
Receipt description: "FHB CB/Car/VD Splin F th"
Cost: £19.99

Except it turns out that doesn't fit. Different gender. Drat.


Protocol for downhill cyclist overtaking a car?

Please accept my apologies on behalf of cyclists. Hollerin' something at a motorist who was trying to figure out how to handle an obviously unclear situation was inappropriate. Thanks for doing your best and not killing any cyclists that day!

In general, I agree with the other answers here that you handled this fine and there isn't some magic you could have worked to make the situation go away. Having frequently cycled one of the curviest and steepest highways in the US, I have often been in the position of your cyclist. I also know from a drivers perspective of the same road that there are not a whole lot of obvious moves.

The primarily impetus for any action should probably be on the cyclist. As a motorist being aware helps a lot; but don't try to do anything fancy. Keep it simple. Watch for what kind of move the cyclist wants to make and adapt, but be consistent yourself. He's trying to guess how your car is going to behave -- if you change patterns on him, all bets are off.

The easiest place for a cyclist to pass is usually the place where cars naturally go the slowest. This means curves. Straights are hard because cars speed up (and try to pass each other). While we do have to follow the rules of the road, passing on a double yellow curve is sometimes the safest thing to do on a bike. Inside curves (left turns for US folks) provide the most visibility and a chance to cut a shorter path than the car. The best thing you can do is stay all the way in your lane and take the curve easy. Let the cyclist make the move. You don't have to be in the shoulder or pulled over or anything, just keep your own company and don't wander all over the road yourself.

It's ok to brake. Cyclists have brakes too and there is no physical reason we are forced go fast or follow close. If you want to be extra nice, when you do brake, touch the brakes lightly at first so your brake lights come on early and gradually add pressure to slow the car. In fact, if a cyclist is following you too closely and you are uncomfortable, tap the brakes a couple times to signal you need room to brake. You don't have to actually brake, but the brake lights are the best signal you can give to indicate you want the cyclist to add some distance.

Turn signals are confusing, but usually a right from you means you are going to pull over and a left means you can see the road is clear to pass. However, these are not set and stone and the cyclist still needs to make a judgement call. Hazard lights are even more confusing: I would save them for indicating true hazards.

To make a long story short, drive normally and safely yourself, and let the cyclist take care of the passing.


Correct spoke tension for DT Swiss EX 471 26" 32h rim paired with Wheelsmith DB 14 spokes

I believe DT has a blanket recommendation of 1200Nm for all their rims, or 122 kg-f. You could email them to corroborate but that number should be safe.

Use the tensiometer chart for the thin section of your spokes. By the same token, always position the tensiometer such that you're isolating a thin segment for measurement. If you had any of the thick section in there, the spoke would deflect differently and the measurement would be useless. Wheelsmith spokes have long butted sections with very short transitions, which makes it easy. DT spokes are the opposite, making tensiometer position fiddly at times.


Replace rear deraileur without breaking the chain

You're likely to destroy the derailleur by doing that too many times.

KMC and Wipperman both have 10 speed quick links which are a better thing to do. Note that you'll need a chain big enough for the larger cassette (or, with a quick link have 2 chains).


What are the steepest, highest, most miserable road ascents in the world?

Road climbs are graded according to elevation change and overall length. The classifications start at "category 5" and go upto "category 1" and finally "Hors Category". Here's a list of "Hors" climbs from the Tour de France throughout its history. These are the hardest road climbs that are doable (at a non-embarrassing pace) by elite athletes.

Generally speaking, cat 5 and 4 climbs can be found in places with non-mountainous geography. Cat 2 through Hors climbs are hard to find in anyplace but very mountainous areas. If you do a cat 3 climb on a group ride-- it will be remembered and talked about. Going up a category usually means that both the grade and the distance is harder. I believe that hors category climbs are sometimes classified as such because of the conditions of the road (eg gravel/dirt is much harder at 15% than asphalt).

You can see informally categorized grades if you use the Strava app (it tells you the category of the climbs you did on recorded rides). If you're interested in challenging yourself this is an excellent way to measure and compare progress because top times are recorded for each categorized climb.

Here's an example of a ride with very heavy climbing yet "only" cat 3/4 hills, it was the Rapha 2011 Gentlemen's race (video). For non-elites, this would be a tremendous accomplishment.


There shouldn't be any amount of liquid oil in the shifter, just some grease.

Looks like some grease is getting out of the holes in the rubber grip and onto the outside.

Regular detergent is not strong enough to wash away grease. You need a proper degreaser product. The citrus based ones are quite good, and available at regular hardware stores.

Obviously the rubber grip needs to be replaced. It's letting grease out and - maybe more importantly - water in. With a Walmart level bike, replacing the whole shifter isn't very expensive. Figuring out what exact model the shifter is can be  difficult though.

The rubber grip should not be worn after a year's light use. Perhaps it was damaged by something sharp. You may be able to glue the holes shut with a rubber cement.


How do I figure out the right size seat post for my bicycle?

The most important characteristic will be the seat post diameter. To determine it, measure the internal diameter of the seat tube, that is, the one which the seat post inserts into. Make sure you do not confuse it with the tube's external diameter, it is not needed.

Use a precision caliper for that, your measurements must be accurate to 0.1 mm. Do several measurements and then find their average.

Available bicycle seat posts diameters vary from 25.4 mm to 34.9 mm; maybe even wider or narrower posts exist. When looking for a new seat post, choose the one that has the diameter closest to your measurements.

The next characteristic would be the post's length. Generally, the length you want depends on your frame size (measured as letters XS, S, M, L, XL or numbers in cm/inches). Unless you buy a super-short one, however, there is less opportunity for a critical error with length. If nothing else, then a seat post that is too long can often be cut to be shorter. But if you make a mistake with diameter, it would be harder or impossible to accommodate that post to the frame.

The majority of saddles are compatible with the most of seat posts. Typically there are two metallic rails on the saddle and a clamping mechanism on the top of the seat post. In certain disciplines, like dirt jumping bikes, a saddle may be integrated to a seat post.


Is it normal to need to replace my brakes every few months?

That seems too frequent and perhaps something else is going on with respect to cable tension that is preventing you from applying maximum force through the brake assembly.
For instance, if you still have material left on the pad and just feel like when you pull the lever in all the way that you are not slowing, then perhaps there is too much slack in the cable in relation to the resting position of the lever.
On my bike, I can use my barrel adjuster to get the pads the right distance away from the rim such that I have very little play in the lever before the pads touch the rims. If you have more than 1-2mm between the pads and the rim, then that is too much space.
Hope that helps and for a frame of reference I have several thousand miles on my Shimano 105 brakes, but I don't have too many major descents where I am really pushing them.
---- Edited Due to Pic Posting-----
Yes you have disc brakes and with the rust on there, it looks like you potentially could have a caliper that is sticking. I assume the pads are worn to the backing material when you take them off correct? If so, most likely a caliper that is not releasing for some reason or another.
I only have experience on car disc brakes, so will let someone else comment regarding the bikes, but if you have a sticking caliper, replacement of it/faulty parts perhaps is best vs. eating through pads and eventually the disc.


MTB Shimano MT610 crankset with 32t: possible switch to 30t?

Yes, you can swap for a 30T chainring. The Shimano page (link you provided) states that the crank arm is compatible with a 30T ring, and they provide a link with a part number (Y0K430000) to the exact Shimano chainring that would replace your 32T.


How will swapping drop bars to butterfly bars affect bike fit?

Not really. The rear position on butterfly bars is about like riding on the tops with drop bars (or riding on flat bars), and that seems to be the "default" position, as that's where the controls are mounted. The outboard position is a bit like the ramps on drop bars, although higher up and much wider--road bars are rarely more than 440 mm wide, butterfly bars are more like 580 mm wide--in order to have the same reach in this position, you might want a shorter stem. Drop bars don't really have an equivalent to the forward position.
There's nothing wrong with using trekking bars, but I think you need to evaluate them on their own merits, rather than as an approximation of drop bars.
Drop bars these days tend to have a much shallower drop than when that bike was built, and I'm guessing that bike has a quill stem, which means it's easy to raise and lower. You might be able to get a relatively upright position even with drop bars.


Of course the more the cleat interacts with other surfaces, the more it wears.

My experience with SPD-SL cleats is the "primary unclipping foot" wears down a bit quicker, although I usually replace both at the same time (partly for convenience, plus I find the yellow "walking grips" wearing out more evenly, so are worth replacing as a pair)

Similarly, the pedal on the primary-unclipping side will likely wear quicker - for example, after around 15,000km:

The SPD-SL pedals show wear nice and clearly; you can see I primarily unclip my left foot. The left pedal had significant vertical movement, and was overdue for replacement.

  Is the action of inserting the cleat that damaging? or is it the standing on the right foot while waiting?

These will cause different kinds of wear, typically.. What is causing the wear should be pretty obviously if you look closely at how the cleat attaches to the pedal, or what contacts the ground when you stand (easily done if you take of the shoe, and clip in with your hands!)

For example, with the SPD-SL cleat:

The yellow bits (1.) will wear from standing, whereas the area that rubs (2.) will wear from unclipping.

Different types of cleats will be different, e.g the SPD "mountain biking" shoes have a recessed cleat, so standing will not wear the cleat.


Is there way to fix a disc brake rotor if slightly bent?

Yes. Disc brake rotors can warp a little in use, or get bent from impacts and straightening them is routine maintenance.

The basic procedure is to find spots where the rotor is bent inboard or outboard, and carefully incrementally bend it back. There are tools made for this purpose (e.g. Park tool DT-2) but the job can be done with a large adjustable wrench.

There are many tutorial and how-to videos that show you how to perform the procedure. Here's one from Park Tool.


Removing top cap and stem from Acros headset?

Nevermind, yes I am an idiot. You literally just pry the top cap off.


Restoring the original color of metal and chainrings

I doubt you're going to be able to get the original color of the metal back, and the rust is pretty much aesthetic, so don't worry about it.

If you really want to try this, you'd likely need to take the chainrings off the bike (which may require a crank puller, which you likely don't have), use something like phosphoric acid to remove the rust, then either paint them or powder coat them or something to prevent the rust from coming back. By the time you've done this, you could have probably bought a cheap new/used crankset that was rust free to begin with.

Or, you could just leave it and not worry about it, like a normal person.