Trek7200: new bracket,crank,chain,&shift cables. Deraillers set Trek manual. Good stand results, but stumbles riding up incline

If indeed the "stumbles" refer to the chain skipping on the rear cassette gear, a simple fix is to replace the cassette. I note that the cassette (8 speed seemingly from what I find on the net) is the part of the drivetrain that you did not mention changing. Its gears wear just as do the chainrings on the crank. Similarly to the crankset, the middle gears tend to wear the most as they are the most frequently used.  The cassette gears and chainrings would have worn along with your previous chain, and now the new unworn chain matches the new chainrings, but not the still-worn cassette gears.
Thus, the chain is likely skipping over the still-worn cassette gear teeth, especially (or only) when under load.


Remove bearing cartridge on a Formula RX-142 hub

Ideally you'll need a blind bearing puller to extract the bearing, most decent bike shops should have one handy.  There doesn't appear to be anything preventing removal of the bearing, so the indents are not for bearing extraction.
If you're lucky you can get in from the back of the bearing and simply punch it out with a hammer and punch, as bearings are simply a press fit.
The tooling indents are most likely for the freehub mechanism removal.  You may have to remove the freehub if you choose to go with the hammer/punch technique; they're not always easy to undo, as most designs tighten under pedalling forces.


Practice.

I moved to hilly area a few years ago: I now climb hills by standing on the pedals in a medium gear. I used to climb hills sitting down and "spinning" n the lowest gear, and sometimes stopping half way up to catch my breath.

I used to stand on the pedals for a few strokes before getting exhausted.

Now I can do it (stand on the pedals) for about 100 breaths (long enough to climb a steep little hill).

I deliberately practice on hilly routes. I've never practised only going up and down a hill repeatedly because I fancy that would be boring, but I also avoid sticking to the flattest routes because I'm lazy.

It takes me 20 minutes of riding to warm up, fortunately I start at the top of a hill so the up-hill is after I've warmed up. My most regular ride down to the river, and half an hour along the (flat river), and then home via half an hour of hilly route (ups and downs, slightly more up than down).

It took me quite a bit of practice, if you're younger than me I guess you'd need less.


Noise after hard braking is normal. The rotor heats up and warps slightly.
When you got rubbing after reinserting the wheel, that shows you didn't align the wheel correctly. You need to be applying as much downwards force as possible while tightening the QR in order to seat the axle in the dropouts. The one-sided force from tightening a QR skewer tends to twist the wheel askew, so you need to be pushing down the whole time to counteract this force. You can practice this by repeatedly removing and reinserting the wheel: once you no longer get rubbing, your technique is spot on.
And yes, you should just ignore the occasional noise. There's no safety issue or anything, and unless you've already purchased $1200 CeramicSpeed jockey wheels, there's no point chasing the performance benefits of eliminating minor rubbing either.


Chain wear due to standing while pedaling

The amount of force required to plastically deform a steel chain is much more than a human can exert, even if you embedded the rear wheel in concrete so that all the force went into stretching the chain, rather than turning the wheel.
Chain "stretch" is 100% caused by wear, with grit in the chain grinding down the rivets and sideplate openings. Standing up to pedal has nothing to do with it. If the chain is dirty and its parts are moving relative to each other, the parts will wear down.


It should be quite possible. Even the rear wheel hub might work as is if it really is a cassette (most likely CS-H072 12-28) and not a freewheel. You will also need a new bottom bracket with the new chainset. You may decide whether to keep the brakes or not, it is possible.

Overall it will not be cheap and you will have a cheap frame with a good groupset and potentially cheap wheels. It is up to each individual to decide whther it is worth the investment. Cheaper groupsets, like Sora and Claris are also decent, but have less speeds. Again, up to everyone's individual decision. The no-longer needed components can be sold, but will not be worth that much.

I would suggest to think twice about the 3x cranks. They are not very popular today, because modern modern gearings allow wide range of gears with 2x cranks. The difference between those two chainrings is now most often 16 and that is more than it traditionally used to be. With 10x speeds in the rear the spacing still should be good enough even though modern rear derailleurs allow cassettes with a wider gear range.


Identify year of specialized s-works tarmac?

Looking on bikepedia.com, I can only find listings from 2012 and 2013 for Specialized Tarmac SL4 Pro, or S-Works Tarmac SL4. The frame in the photo seems to have decals for both 'S Works' AND 'Pro' (on the seat tube). This seems inconsistent with any photographs I can see on google images. SWorks frames tend to have 'SL4' on the seat tube instead but I have only seen photos taken from the drive side.

Also, the colour of the red decals on the bike seem a suspiciously similar shade to those on the wheels, which makes me skeptical even further. I haven't seen any google images results in this paint scheme, and expect that you haven't either, hence the question here.

I would ask the seller for more information, for warranty documentation, proof of purchase, a frame number that you can check with Specialized etc. Maybe it's all legit and original, or maybe it's been resprayed. If so, the owner shouldn't have any issue with answering your questions. But if it seems too good to be true, be prepared to walk away.


Several reason come to my mind:

The temperature at which you were using it. LCD displays get notoriously slow at low temperatures. You mention -8°, was it right then when this happened? Things should go back to normal at room temperature. The computer will still be working normally but the display literally freezes. The phenomenon is well known to people who own an early LCD wristwatch. They became unreadable in the cold.

At low temperatures, the battery either 3V lithium CR-type cell or Li-ion rechargeable slow down because of chemistry slowing.
If the battery is a CR-cell it might be reaching the end of its life. Your device may be new but the battery was already inside for a while when you bought the computer or the cell is faulty.Try replacing the battery.

But then since your device is quite new I'd advise you to take it back to shop who sold it to you as warranty is still applicable.


What do I need to consider for a cheap wheel for a Specialized Tri-Cross to use on a trainer?

From your other question we know you have a Specialized Tri-Cross 3x9 with an XT MTB derailleur.

This is what you need to know:

Rim brakes and quick release hub.
Rim diameter: ISO 622 or '700c' - you can look up bicycle wheel rim diameter conventions
Rim internal width: You can go a little narrower or wider than 17mm as tires work on a range of rim widths. Check the min and max rim widths of the trainer tire you will be getting.
Hub width (between the frame dropouts); Your bike will either be 130 or 135mm. It's easy to measure with the rear wheel out.
8/9/10 speed compatible. The cassette freehub body width for all those speeds is the same. On 11 speed wheels it's a little wider to accommodate 1 extra sprocket.

You don't care about spoke count, weight or stiffness so you can literally get any wheel that meets those specs. I'd look around on Craigslist or Facebook for a used wheel - but make sure it's reasonably true and the hub bearings are not worn out. Alternately you can get a new cheap wheel from either your LBS or one of the online bike component stores.


If you have a modern BMX then the saddle should be super low. If it is not then move it at the very bottom.

BMX bikes are very very stiff (100psi tyres, rigid cromo frame, rock solid wheels) so you need to absorb the imact with your feet and upper body. Landing with the rear wheel first (just slightly) helps trigger the feet at the exactly correct time. Another thing that helps is that when you start descending (from the bunnyhop) you extend your feet in order to give yourself enough room for absorption.

If you don't absorb with your feet then the weakest link will have to deal with the whole impact (knees, pedals, head tube of frame etc).

Keep in mind though that parts do fail. Broken pedals and bent rims is not something unexpectable in the BMX world.


How to repair large holes in inner tubes?

I don't think that you will have a problem with the patch ballooning out as long as the tube is inflated while fully mounted with rim and tire. To my experience there just won't be any room to balloon to.

If you fear that this will be a safety risk, I would recommend a new inner tube when the old one has such a big hole. When you are on a ride and have no spare tube at hand, even with a 2-3 mm slit a standard patch should be enough to get you home.


Why does my right Achilles hurt when I use my Sidi S Pros

I've had some bad pain in my Achilles before. For me, it was a problem when I did a long ride with my seat too high and using SPD shoes and pedals. Because of the seat height, I was bending and flexing my ankles to push the pedals slightly at the bottom of each pedal stroke, this is called ankling. If you find yourself doing this, creep your seat down slightly and watch your pedaling form to see if that removes the need to apply force with your ankles during the pedal stroke.


What's the best way to shield a rider from the wind in a group (most aero position in the group)?

When you're in font of the rider that you want to help,  then the more aero you are, the less shelter you give.

Riding in a low body position, head tucked and arms narrow makes it easier to ride at speed, but means that you aren't puching through the wind as much for the rider behind you.

You'll want to sit as upright as possible, arms a little flared with your head held high to push as much of the wind as possible, with the added bonus of this slowing you down as well. If you really want, you could even unzip the jersey a little to have it flapping in the breeze a bit.

The last thing that can make a huge difference is how you pace the effort. The rider sitting in will generally get more of a draft the faster you ride. This means that when riding the flats or downhills, you can go about as hard as you want, then on the climbs you just ease up to a comfortable pace for him. In a headwind, it is very easy to hold a wheel, whereas a tailwind will make it far easier to drop him.

You also want to absolutely minimise surging when you ride. When you want to accelerate, gradually ramp it up rather than jumping away and putting a gap into him. Things which make it much harder to sit on are weaving about while riding or getting out of the saddle regularly, throwing your bike back. If you hold your line and make a hand gesture before getting out of the saddle, then the rider behind can sit much closer to you safely.


In this manual, they state the torque for the Giant Defy seatpost should be around 50kgf-cm (5Nm). I know this is for the carbon frame, but they should be similar.

You can buy a torque wrench for around $30, which you should, because otherwise there is a high chance you will under or over tight it. I know $30 is a pain in the ass, but think this will keep your $1000 bike running smoothly for a long time.


I don't see any chain in the video.  It (most) will do that with no chain. The spring is (hopefully) strong enough to pull an untethered derailleur into the cassette.
Park Chain Length Sizing

Now the derailleur may also be bent but that is something different.

The rubbing in that video is only a problem if it rubs with the chain installed.


Single-speed vs Multi-speed bike purchase

Single speed bikes tend to be very low end bikes--aside from fixies, but those are a different animal altogether.  As such, you almost certainly will want a multispeed bike.  Don't get too focused on having a specific number of gears.  Instead, focus on a bike that meets your needs.  For commuting, you'll mainly be looking at commuter bikes and road bikes, and you'll likely be looking at a derailer bike with at least 16 gears.

Visit some local bike shops with absolutely ZERO intention of buying something that day.  Depending upon where you live, the selection of shops may range from great to sparse.  Get a feel for the place and how they treat you.  The customer experience will range from great to awful.

I strongly urge that you stay away from big box stores and only shop at local bike shops.  You will have a far better selection of bikes at a local bike shop, and service is non-existent at big box stores.

What's available at bike shops in your area may be completely different from what's available in my area.  As such, it's impossible for anyone on the Internet to make specific recommendations.  It's best if you look at the inventory of bikes in shops in your area.  Something that you have to custom order or drive 100 miles to pick up adds a lot of unnecessary expense and hassle.


How to measure and treat BSA bottom bracket housing misalignment?

The threads on bottom bracket shells can have angular misalignment. The threads are typically cut in two operations, one from each side. If the shell is not aligned properly in the jig when the threads are cut misalignment is the result.

Misalignment should be fairly easy to diagnose at least.

Install the cartridge only from the drive side making sure to not cross thread it. If you look at the non drive side you should be able to see if the body of the cartridge is centered in the shell on that side. That will tell you if the drive side thread is aligned.

You can also install the lockring and see if its flange lines up with the edge of the shell (this is not a great indicator of thread misalignment , because the edge of the shell may not be true).


Vintage bike - help with chainring replacement

I believe I have that same crank on a roughly 1983 Schwinn World Sport (see image). I got it used, so I don't know if it was the original, but in any case, mine has 40 teeth on the small ring and 52 on the big ring, so that's likely the size you're looking for.

That said, it might be easier to find a replacement for the entire crank+chain rings rather than match that chainring. Mine is a standard square taper spindle, and many vintage cranks that would fit are available on eBay etc.

If you live in a city with a co-op that salvages old bikes, they often have loads of cranks from that era that would fit.

Furthermore, since the square taper spindle was a standard for so long, a more recently made crank is also an option.

UPDATE: Images online seem to indicate this crank was standard on early 80's World Sports. Given how many of those bikes are still around, which means the cranks should be relatively easy to find, or you could easily find a whole bike and take the crank off if it's really important to you to match your original.


How to pass a bicycle while driving a car

The problem is ambiguity.  Sometimes you'll be unfairly judged by cyclists you're trying to pass.  It will happen.  Sometimes it helps to reduce the sting of the judgement with some perspective on what's going on.

When you’re on a bicycle, cars are death monsters. You spend your time trying to keep distance from them. You wish they would all just disappear. Even when they're trying to be friendly. It’s like you’re walking around in the woods, and suddenly you’re approached by a woodcutter who wants to have a friendly chat with you, but he’s carrying a running chainsaw casually in one hand, and walking really fast. What are his intentions?

Same sort of thing with drivers zooming up to you. People don’t even realize their mistake, because most people have never had it happen to them. Cross-country bicyclists deal with it all the time.  (I am one of those.)

People will cruise up within inches of you at a stoplight and ask “where ya goin’?”, expecting an answer while you’re madly trying to determine if they intend to go straight or turn right when the light changes, potentially obliterating your bicycle and ending your life. If you don’t respond, you’re being rude.  It sucks for everyone.
People will honk their horns at you as they drive by, startling you as you attempt to balance on a narrow strip of shoulder, and unless you look up into their window and parse their faces and their upraised hands, you’ll never know if they were honking because they want to encourage you and cheer you on, or because they hate the sight of you and intend to plow you into a ditch.
People will slow down to a crawl behind you, stacking up the traffic, even though you’ve given them the entire open lane to pass you by, while you ride over rocks and garbage in the gutter to make yourself as small as possible. They will hover there, and you have no idea if they are displaying chivalry and waiting for a clear oncoming lane so they can veer into it and give you a wide, respectful berth – or if they are malevolently cursing you for having the nerve to ride such a ridiculously slow contraption on their highway, and getting ready to scream at you or throw something at you from an open window as they shoot forward. You have no idea because you can hear them, but you can’t see them.  Or if you have a rearview mirror (like I do, and like I recommend every cyclist obtain), you can see them well enough to know there's a car there, but you still can't see their faces.

In all of these situations, people are either trying to be model citizens—or they are planning to seriously endanger you—and you have absolutely no idea which it is until it happens.

I was driving my car across Nevada once.  It was sweltering outside.  I passed a cyclist slowly rolling in the other direction and I knew he would be thirsty.  I turned around at a pullout and went back the other direction, passed him again, then went another half a mile ahead of him before I slowed down and stopped.  Then I shut off the car, got out with the water bottle in my hand, clearly visible, and waited there while he closed the distance.  It was a gallon of water and he was grinning ear-to-ear as I handed it to him, and sure enough he drank half of it on the spot, in one go.  He'd underestimated the heat of the day and I knew he had another 50 miles to go.  We had a great chat about touring and took a few photos together.

I wouldn't have known to approach him that way if I hadn't already had a dozen encounters of my own on long tours.  And I have to take the rarity of this knowledge into account, for however long I ride:  People just aren't going to know what it's like.  It's always going to be ambiguous.  They will always scare you without intending to.  And you just gotta accept that your life is in their hands and hope they mean well.

So, it's a scary situation, and there aren't very many good ways to reduce that fear.  But there are a few:

When you're interacting with a bicyclist, never honk your horn.  If they're new to the road, just the sheer surprise of it might make them accidentally steer into a ditch.  With experienced riders, you can sometimes toot your horn after you've passed them, while also waving to show you're not furious, but usually just waving works as well.  Believe me, they're got their eyes on you at that point, they'll probably see you wave.  And that'll make them smile and feel relieved, which is great.  We're all on an adventure together!
When you see you need to pass them, be assured that they see you and are trying to do what they can to make that pass happen so you can both be rid of each other as soon as possible.  With this is mind, try to hang back as far as you can while still keeping your own view of the situation in the oncoming lane.  The closer you hover by a cyclist, and the longer the time, the more nervous they become.  What's worse, sometimes long-range cyclists attract a lot of attention just because of their gear, and people will hover behind them just out of curiosity, which they find frustrating, especially when there are other cars around to complicate things.  But that's not your situation, and it's rare in general.

Do your best to drift back as far from them as you can until the opportunity to pass presents itself.  The very fact that you are drifting back—that you were closer and now you're farther—will signal to them that you are taking things seriously and understand their perspective.  That said, number three:
Pass as soon as you safely can!  Get out from behind them and get on your way as soon as the visibility and the space is adequate.  If you're not on a busy road, chances are the cyclist was riding in relative peace and quiet until you appeared, and is eager to get back to that, rather than this constant state of panic.  The longer you linger back there the higher his/her panic will rise.  Every cyclist, everywhere, would much rather have you ahead of them than behind.  All that deadly force is then pointed the other way!

Please employ these tactics.  Every cyclist on the road will appreciate it, even if some of them still react badly in the moment.  It's sometimes just a no-win situation that way.  But believe me, most of us really get it—we're all drivers too (unless you're in a dense urban environment where cars are optional)—and we'll truly appreciate that you hung back, then made your move ASAP.  The almost businesslike appearance of this when it's executed well is especially refreshing.  Thank you for asking this!


Electronic bike keeps getting flat tire on the back

If you have an e-bike with a rear hub-motor (and with the battery pack over the rear tire), you should note that you have considerable unsprung weight on that rear tire. You should try to make sure that you have the tires properly inflated -- on the high end of the maximum PSI the tire can handle.

Try to ask your LBS when you're replacing the tire what type of puncture you're getting. If you are getting pinch flats, then you need to think about inflating your tires to a higher pressure. If that's not possible, you can also explore getting wider tires.

If you're getting road debris punctures, then kevlar belted tires will help. Also, as ow3n notes, having some sealant inside your tube might help although I find that this often just creates a huge mess when you get a flat that is too large for the sealant to contain.


Bag for holding valuables on bike while parked?

Leaving valuables on the bike sounds like a very bad idea. Bike luggage just isn't going to be robust enough to resist theft if left unattended, and the whole bike itself may be vulnerable to theft.

What you want is a bag or caddy with a quick release so you can easily detach it and take it with you when you leave the bike. Many saddle bags have a quick release and come in a range of capacities.


Measuring tension in double butted spokes

Tensiometers test deflection and their charts make the assumption that the entire section being used for the test (the entire length of spoke between the tool's two contact points) is a uniform thickness. That way that section is isolated - if there were any of the taper in there, it would throw off the reading. So you always make sure the tool is touching only the thin section, and you use the chart entry for the thin section.


Does Strava display live watts while biking?

Not with the free version — it displays a delayed average. If you sign up for the premium program you get real-time, live monitoring.

What you can do to get live Watts is to use another program (for example the one provided by your wattmeter) to record and view your data live — then export the track to strava after the fact.


How do specific tubeless valves compare to bodging it with a cut-off tube valve?

I've seen it done that way when the whole tube is split and used as a liner to make a tubeless system out of a non-tubeless wheelset.  As pointed out in the comments, if you already have a tubeless wheelset, the couple of bucks you save probably isn't worth the hassle you will experience trying to get the "bodged" valve to seal to the rim.  It might make more sense as an emergency measure if you have destroyed a tubeless valve.


If it's just the wire that's not working, I'd replace the housing and cable for that wire to make sure there is no gunk or anything keeping it from moving freely.

If it's the brake, and it is a rim brake, the first thing to do is play with the screws that are on each arm of the brake. The farther in the screw is, the more tension is on the brakes spring which will help pull it back out. See if you can tighten that enough to get it moving enough.

If not check the mount points on the frame. A lot of the times there's a spring hidden inside the mount point which helps provide the return force for the brake. Generally it's three small holes in the frame which the spring will go through one, and then the spring is also pressing against some plastic housing, so if the plastic is damaged you'll need to get a new brake. If it doesn't looked damage, try changing it to a different hole to provide more return force and grease/clean the whole thing.

I'm speaking only generalities though, a picture or name of the brakes would be great.


Why is there a koozie on this bike's chainstay?

That is a "chain stay protector" and it is installed in, let us say, a non-traditional way.  Typically it would be a couple inches forward of where it is.

As the name suggests, the purpose of the pad is to protect the chain stay from wear and damage from the chain, which can hit the stay with a lot of force when riding at high speed over rough terrain.


Are 130 BCD chainsets stiffer than 110 BCD?

There's little difference noticeable but the chainrings will make a big difference as some cheap ones will flex a surprising amount


Able to shift to final gear on bike, but not on smart trainer

When it's a 10-speed bike involved in this situation, here is the calculus:

If someone put a cassette spacer on the trainer wider than the proper 1.85mm 10 to 11 speed conversion spacer, it causes this problem because then the small cog is out further than the RD high limit screw is set for it to be.
If the trainer does have a 1.85mm spacer and still doesn't work, and both cassettes have any included 1mm spacers on that they came with, the assumption then becomes the hub is locating the small cog in further than standard, which is why using the techncially right spacer on the trainer is seeming to put the small cog out to far. The solution then becomes use a thinner spacer on the trainer.

Make sure your hanger alignment is perfect.


Can a 12 speed Shimano micro spline cassette be used with SRAM Eagle 12 speed components?

SRAM and Shimano 12 speed are cross compatible. The pull ratio is slightly off (offhand I believe it’s 1.76 for SRAM vs 1.7 for Shimano), but it seems to work fine in the real world.
To get the nice Shimano “Hyperglide+” shifting, you would need both a Shimano cassette and chain. It would shift without it, just not as well.
Of course, you cannot use SRAM XD cassettes on a Shimano MicroSpline freehub body or vice versa.


What is the "preload" setting on the front fork suspension?

This fork setting exists so that the fork can be customized to your weight (major reason) and riding style (minor reason). It's simply the initial compression of the internal spring in the fork. The more it's compressed, the stiffer the fork will feel.

Bigger preload compresses the spring more, and so it's best for heavier riders and/or people who need/prefer the stiffer ride (racers etc.)  Lighter riders should use less(-) preload. Less(-) preload will also give you plusher ride, but the bike will e.g. dive more during braking.

Source: http://bicyclethailand.com/setting-the-sag-on-mtb-suspension-forks/


I'm familiar with RSX brifters (brake and shift combo units)  If that's what you have then its likely the grease has gummed up, stopping the under-lever from engaging the release.

You might be able to finangle it a couple times by manipulating the underlever carefully, and you'll feel it catch.   A blast in the guts of the brifter with brake cleaner or similar can help short term too, but for the long term fix its at least an hour of messing around.

Here's a pre-existing answer where I wrote up the full procedure for cleaning a RSX brifter:

STI shifter sometimes doesn't catch in cooler weather

And here's the howto video showing... how to.

Answer: if a squirt of brake cleaner helps, then the full fix should make it right again.


Is there a spoke light that is ultrabright?

the thunderbolt comes stock with rubber straps, basically long-lasting rubber bands. the bike in the video has aerospokes, which would be thick enough to keep the light well secured.  aerospokes are uncommon though; typical wheels have 32-36 2mm steel spokes, which wouldn't provide much to grab onto.

there are plenty of other spoke lights out there which are designed for 2mm spokes.  i would check what kind of wheel you have before you go buy anything.


Up until 1952 serial numbers we printed on the Bottom bracket shell, after 1952 they moved them to the rear dropout until 1971 when they were again moved, this time to the head tube beneath the oval badge. Being on the cusp of years i would check both the BB shell and the rear drop out. This information can be found in an informational bulletin released by Schwinn here.

I doubt you will do to much damage with a wire brush, as long as there is not good paint on the frame, which will be scratched from a wire brush. You may also consider using a rust eliminator such as CLR (Calcium Lime and Rust), it could be sprayed on with a spritzer style bottle and rinsed off with alcohol or water. Light brushing along with this may be enough to make out serial numbers.

Once you find it This web site may help you decipher it's model as well as date of production.


Mark your tire where the tube's valve stem is located, remove the tube, inflate it and put it in a bucket of water.  Look for bubbles. This is where your leak is. Now inspect the tire and rim at the correlating point for something that may be causing the leak.

Good Luck.


What is a sign that my chain needs to be lubricated again?

If you hear your chain squeaking you definitely need to re-lubricate it.  It's also a good idea to re-lubricate after riding in wet weather since the combination of road grit and water tends to strip away the oil/wax.

For more detailed recommendations, see this question:  "How often should I lube my chain?"


You have a Shimano 105 5603 series 10 speed shifter paired with a Ultegra 6700 series 10 speed rear derailleur, as those are both 10 speed they will work together.
Those will not work with a R7000 series 11 speed cassette. Even if you thought you could just select 10 sprockets out of the  11 that does not work. Sprocket spacing is different between 10 and 11 speeds.
Also the HG CN-6701 chain is 10 speed specific and would not work properly on an 11 speed cassette.
Get a 10 speed cassette to make this setup work.


A lot of people do this, enough that at some points it's been a fashion on fixed gears. All you have to do is put the cable through the normal way with the head resting on the back side of the lever, where it will sit in the housing slot. There are some levers that are made to accommodate the cable head there snugly using a removable plastic bit.

The main reason to do it is if you want a flatbar style lever on a clamp diameter they're not otherwise available for, I.e. 23.8, 25.4, 26.0, and 31.8mm, and you either don't want to mess with forcing/adapting a standard 22.2 lever or there's no real way to do it, as in 31.8. If you can just use a 22.2 bmx lever, that's what I would tend to do, because they're generally better brake levers.


Alternatives to Crankset Shimano M523 Octalink 40-30-22T

If you're just riding casually, then a simple chainring replacement is probably all you need.  You don't have to match the styling, just the Bolthole Circle Diameter (BCD) and number of boltholes.     It looks like a 4 bolt pattern, but there are a number of standard sizes (naturally)
Personally I use a 100% printout of the PDF at https://cdn.shopify.com/s/files/1/0230/9291/files/Measure_BCD_5ad6ccfa-f146-4048-ac0f-e2279602c9e1.pdf and then overlay the chainring on the page.  You can see what BCD you need.   From https://www.wolftoothcomponents.com/pages/how-to-measure-bolt-circle-diameter-bcd
The four chainring bolts can probably be re-used without issue, provided you remove them without damage.
Staying with the same toothcount makes things simpler too, though you might choose to change things if there's a need, like if you're spinning out in 40:11.
There's a good chance you need a new chain too.  Based on the wear on the big chainring, its really quite worn.  Depending on how you ride, the middle and grannie ring teeth might be okay, but that big ring needs replacing.
I see no point changing a working octalink BB for something else, until it breaks down, and then you look at what options are available. You have matching cranks already.   If the bike us for a long distance trek or all-day MTB in the back country, you'd want to have decent options so replacing working parts might be reasonable then.  Or if the BB was crunchy and not suitable right-now, then a replacement might be in order.
However I'm firmly in favour of wearing it out - otherwise you're throwing away parts with life left in them still.
Do let us know how it goes too - final followup is always useful.


Completely remove the tire, tube. Check the rim tape is sitting correctly, and remove that. Clean the rim of any debris that might have go inside it and under the rim tape.
With three punctures in the inside take a very close look at the rim tape for any sign of damage. Also check the rim for sharp burrs than may have occurred due to riding on the flat.  If the rim tape is looking good, clean it and reinstall. If in doubt, get a new one.
Its possible that the tube suffered a lot of damage from riding flat, I would put in a new tube, if that punctures, I would then replace the rim tape and tire (and maybe another tube).
Your tolerance for spending money and putting up with ongoing punctures determines when to buy new items. I really dislike punctures, so would be replacing rim tape, tire and tube immediately.


Why does a Shimano centerlock rotor have free play?

The cause is a missing aluminum shim between the centerlock lockring and the
brake rotor.
I removed the brake rotor from the defective front wheel. Then I removed a
brake rotor from a known-good front wheel. When closely inspecting the
lockrings, I noticed something the known-good front wheel has that the
defective front wheel didn't: there was a very thin aluminum shim between the
centerlock lockring and the brake rotor.
When I built the front wheel, having had no prior experience with disc brakes,
so I thought the aluminum shim is something that should be removed and the
centerlock lockring should be tightened without it.
Now I have swapped the lockrings and the brake no longer has free play.
The missing shim probably has been thrown out along with garbage, so I have
to purchase a shim somewhere.


Saddle keep tilting. Which spare to use to replace it?

First thing to do is double check the other side is put together right, namely that the toothy bits are engaging.

If so, probably what's happening is the teeth that are supposed to hold the angle adjustment in place got rounded off from prior incidents of slipping.

These kinds of clamps come in one very commonly seen size, 22.2mm aka 7/8", and a couple weird ones that are mostly the domain of antique bikes. You might as well bring in the old one to match, or put a ruler across it to confirm it wants a 22.2mm post end (different from the seatpost size proper because usually pipe style ones taper at the clamp end). The rail mount part is universal among normal single rail saddles.

Most bike shops with any kind of family/casual customer base accumulate a big heavy box of new replacement clamps because they come with certain brands of  saddle, but most bikes don't actually need them because they have posts with integrated clamps. So from a shop like that they're pretty ubiquitous and cheap.


Can I use a Shimano BL-MT200 lever on a Shimano BR-M446 brake caliper?

The corresponding lever for the ALIVIO BR-M446 caliper appears to be either the BL-T445 or the BL-M425 (depending on the size; 3 finger vs. 2).  You might have more luck searching for those product numbers instead.

The ACERA BL-MT200 seems to have very similar specs to the ALIVIO BL-T445, though based on the angle to the clamp it may stand off the bars a bit further.  Specifically they use the same hose kit, SM-BH59-JK-SS, so the hydraulics should be compatible.  My major concern, however, would be that the Shimano site explicitly notes that the ACERA part has "braking power tuned for entry level riders."

A leak might just be down to the hose - or fittings - though, so you might want to find out if your LBS can service it for cheaper than getting in new levers.


The back brake on my bike is not functional, is it illegal for me to cycle in the United Kingdom?

Yes, technically.

Most sorts of cycle are required to have at least two efficient braking systems, by which the front wheel (or wheels) can be braked independently of the rear wheel (or wheels).

The likelihood of you receiving a ticket, fine, or other punishment is infinitesimal. It could happen, but it almost certainly will not.

Practically, the front brake is much stronger than the rear brake. Most experienced road cyclists almost exclusively use the front brake. Why is it "a bit difficult to stop" in some circumstances?

That said, you should absolutely have it fixed. Having redundant brakes is important for your personal safety. Brakes and brake cables can fail.


Can I change my hub so I can put disc brakes on the bike

We have to assume, as you haven't provided a photo, that the frame has the attachment points for disc brakes already -- certain bikes have a provision for rim and disc brakes and yours could be one of them.
It is unlikely that you will find a disc - compatible hub with the same "flange" dimesions as your current ones. This is where the spokes are hooked into the hub, if you don't already know.
Therefore you will need to calculate the correct spoke length for the new hub and order the correct length spokes in order to build the wheel. It is very easy, and often quite cheap, just to buy a complete disc compatible rear wheel either new or used, unless you want the experience of wheelbuilding.


Freehubs can be removed from the hub and replaced; it involves removing the axle from the hub and then loosening a fixing bolt with a 12mm allen key.
Visit your local bike shop and ask if they have any thrashed rear cassette wheels; if they're cool they'll give it to you free or next to free.  Pull the freehubs and hope to find something compatible; there are several different spline patterns.


Help Identifying this Tandem? Sun Tourer

Looks like a home-made tandem to me.
Here are my reasons:

The captain's seat post has no clamp.  Instead there's a hole, presumably for a bolt to go through the seat post.  That's not done on a purpose-built tandem.  Here someone's cut the clamp off to allow the top tube to continue.
I see a tang at the bottom under the Keel Tube for a chain tensioner.  A purpose-built tandem would be more likely to use an eccentric BB in the front for tension
That tensioner seems to be on the right-hand side of the frame - a normal tandem would have the timing chain on the left side, and would have special bottom brackets to account for this.
The stoker's position has a head tube of its own - normally a tandem would have a special stem that secures to the captain's seat post, bringing both riders closer together.  The larger the gap between riders, the less benefit you get from aerodynamics.
The welding on the stoker's BB housing looks different for the keel tube - specifically its a lugged frame but the keel is butted straight onto the lug, not into a recess.
I suggest you look closely at the rear of the captain's BB shell, for the remains of chainstays that have been cut off.  I do see the stoker's head tube has been extended with new metal that doesn't match, that will also be welded in.  You could also look at the sides of the stoker's downtube for the remains of shifter bosses.
The tube diameter of the additional pipe in the middle is higher than the rest of the frames - so between captain's seatpost and stoker's head tube is noticeably wider tube, as is the keel and the lower stoker's head tube.

The paint job looks like a can of spray paint, specifically where the white fades into the red.  To be fair that's a really hard transition to paint well.
So either the frame builder added some stickers after painting, or they welded it such that the original stickers stayed usable, and only the new welded areas got painted.
Please don't take this as talking down your frame - it will be a loverly bike when you've finished building it.  But don't waste too much time trying to identify the brand, when it could have been made by someone in a home workshop.


You just need to match the size.  Bontrager is just a tire that Trek used for that bike.

The size will be on the tire
The bike comes with a 700x35c
The 700 is the rim size - you have to get a tire that size
The 35 is the width of tire - you have some variance there
For your bike might as well just stay with a 700x35c
For a tube you will get a range like 700 x (32 - 45)


There's no harm in doing so, as long as you identify compatible components.

You do take a hit on cost, by which I mean that components work out a lot cheaper when bought as part of the bike, rather than standalone. So economically it would probably make sense to stuff the money in a piggy bank, and save up for a new bike with better components, since when that time comes you'll get more bang for your buck. But if your pocket is willing to take that hit, go for it.

I haven't looked at your specific case but in general, upgrading from something Shimano to something Shimano will work, as long as both mechs have the same number of gears on the cassette. 6700, for example, is a 10-speed system so as long as 4600 is also 10-speed, you should be safe.

The other caveat to bear in mind (when upgrading brakes/shifters) is that a couple of Shimano mechs have different pull ratios to others. In fact, there was a question about this just a couple of days ago which I remember links to a document explaining what mechs are affected.

Lastly, while I start by saying there's no harm, there might also be no gain either. That's going to depend on you, and on the rest of the bike. So you're right to raise this in your question, but it will result in "no gain" rather than "harm".


Does the diameter difference between road and mountain bike handlebars make some bikes incompatible?

This article and Sheldon Brown are good links to look at for the dimensions associated with handlebars.

In particular, you have to worry about where the stem clamps on, as well as the rest of the bar (where your brake levers & shifters are attached, that is, the grip area) - thus, there are two diameters. The clamp is usually 1 inch for most bikes now (contrary to the first link), but they can differ (older road and MTB bars often use different clamp sizes). Most MTB type components (riser, flat, butterfly, etc.) have a 7/8" rest of the bar while most drop bars (excluding the Walmart ones) are 15/16". So, you can't clamp road shifters/brakes to MTB bars and vice versa.

To summarize the relevant measurements and their applications, see Sheldon Brown's Handlebar Crib Sheet.

In this case, the clamp is right (25.4 mm), but the rest of the bar is 7/8". Your shifters are designed for 15/16" bars. This means new shifters (probably thumb shifters or trigger shifters) and brake levers if you switch to this bar, since you can't really bend STI levers to fit. Also, even if you did manage to get them mounted (with some small shimming or something), the shifting action would be pretty unnatural.

If you want to use trekking bars, I'd probably go with thumb shifters and some short pull brake levers. Note that if you choose to use trigger shifters, they have to be from the Shimano road group (i.e. the Sora flat bar shifters) due to the different cable pull of the road front derailleurs and mountain front derailleurs. Alternatively, you could try a mountain front derailleur with possibly a different crankset (50T/52T rings are big) and use any Shimano mountain bike shifter set, or grip shifts like the SRAM Attack.


Bottle dynamo: the steel wheel quickly wearing down?

The roller of the dynamo should run on that ribbed track under the treads. And the axis of rotation of the rotor needs to point very precisely at the axle of the wheel. (I've always checked that with a piece of string!)

BTW: The roller doesn't look worn to me. It looks as if it had been machined that way, compare with a new one. And you may also find a rubber cap that fits over the steel roller although this will increase the diameter and make the dynamo turn at a lower RPM and dim the light in an unwanted way.


Upgrade/Replacement options for Cannondale Headshok DD50?

"Product Information -- Our Cannondale elastomer kit will make your Head Shox work like new." $42.  http://www.suspensionforkparts.net/eshop/index.php?_a=viewProd&productId=156


Cracked frame riding into the back of car, what's salvageable?

I've worked on a couple bikes that have had frontal impacts.

Check the underside of the downtube for any abrasions or rubber marks.  You might find the front tyre has touched the downtube in the collision, giving you an idea of how far it bent and has come back.

Theres a fold in the downtube and I can see a completely broken top tube, so

  That frame is unrideable as-is.

The unknown damage could include

Front wheel - Check it for trueness both left/right and up/down.  Take the tyre off and check it over under a strong light looking for cracks or damage.  If its aluminium its probably OK, but front wheel failures break people, so you don't want that.
Bent fork tines effectively reducing the rake and therefore trail and handling.
Fork's crown welds have been stressed leading to possible failure later.
Steerer tube may have been bent or distorted out-of-round which will weaken it.
Bearing cups/cones/sealed bearings in headset - they may be fine or they may have imprinted a dent into the bearing race surfaces with impact.  The bearings themselves may have cracked or flaked or they may be fine.
Steerer top-cap and bolts, and spacers.  These may have taken some level of impact and may be not as round or flat as they used to be. You have plenty there to compare, which is handy.

On the plus side I'd expect these parts to be okay (assuming none of them got crushed or incidentally damaged)  so do check them out first before reuse

Brakes, rotors and calipers, lines and levers.
Handlebars, shifters, grips/tape, Stem.
Lights, reflectors and computer/phone
Everything on the bike aft of the drink bottle.  It might slightly scratched/scuffed from subsequent fall, but there should be no damage from the impact with the car.  So your transmission/groupset will be totally fine.

I note that the bike didn't fail you, so don't write it off.

Also, depending on liability, insurance, and so on you might have to discuss ownership with your insurance company.  They may elect to replace it rather than repair it, if you choose to do a claim for an accident.   Also, the car owner's insurance company may have a say in it too.


Schwalbe is one of the few brands that lists tire sizes this way. Their 28's come in two ISO's. Tires listed as a decimal size such as 28x2.0 are a 622mm ISO, while tires with a fractional size such as 28 x 1-1/2 are a 635mm ISO.

635mm are an uncommon size to American markets but can be found on

  "English, Dutch, Chinese, Indian Rod-brake roadsters"

from varying manufacturers and production dates.
From Sheldon Brown

622mm are commonly referred to as 29 and 700C sizes, which are commonly found on current production mountain and road bikes. 29 and 700C tires are interchangeable as long as the rim width can support the size of the chosen tire. For example a 700 x 50 tire roughly equates to a 29 x 2.00 , or in Schwalbe terms 28 x 2.00"

*Answer has been edited thanks to people paying more close attention to the question than I did.


They are telling you what size of lower headset you need in terms of the Standardized Headset Identification System (SHIS).

This is a naming system that tries to simplify headset standards in part by rounding as much as possible to the nearest whole number.

This frame's lower bearing interface is a very common size known under SHIS as IS52, otherwise known as 1.5" IS. The frame bore size is around 52.1mm and the bearing OD is exactly 52.00mm, hence the simplified name IS52. The /40 and the /30 refer to the crown race. If you were using a tapered fork, it's got a fork race seat OD of 39.8mm and a crown race ID of 39.7mm, simplified to just "40" under SHIS. If it were a straight fork,  the fork race seat OD is 30.1mm and the race is 30mm, simplified to just "30".

What's confusing about what they've done here is that on their spec page, for the headset upper they only say "Integrated Campy Spec Upper Bearing (45x45 degree)." They probably should have also said IS42, which is the SHIS name for the same thing. As for the reason they're mixing standards like this, it's because the Campagnolo Hiddenset standard got an early foothold within the BMX/DJ world and is the standard to this day, and a lot of the headset uppers (key logo display points) people will want to use on frames like this use that standard, but they also wanted to make a frame that could take both tapered and straight forks, which wouldn't have been possible with the Campy standard. So you need a more BMX-y upper. If you have trouble finding just the upper, buying a whole headset isn't too bad of a waste of money because you're mostly just paying for an extra bearing, which you use as a spare when the first one wears out.


Bladed spokes are used on rear wheels, which must have cross lacing on the drive side at least. Disc brake wheels obviously require cross lacing front and rear too.

You'll tend to see bladed spokes with low spoke count and radial lacing together because they are all elements of higher performance wheels. However,  I don't see why bladed spokes would not give some (perhaps slight) aerodynamic advantage if used on high spoke count 3-cross wheels.


Replacing an ebike's cable disc brakes with hydraulic disc

Assuming you have eliminated contamination of pads or rotor as the cause you can consider a different calliper.
The bike spec on the website lists the brake spec as “Mechanical disc with alloy 3 finger levers.”
A drop in replacement might be an Avid BB7 or BB5 or Shimano BR-M375 calliper which might improve the strength of the brake without needing to figure out the mechanics of the cut-out switch at the lever.
However, mechanical disc callipers can also depend on good pull ratios at the lever to work well so you might need to figure out how to reproduce the switching mechanism with a new lever if a new calliper doesn’t give you everything you want.
The carrier metal of the pads is red because it looks cool. They are probably organic type pads for when it’s time to replace.


What to check after blowing tire off rim

I'd change it for a better tire, one that's much tighter on the rim.

You inflated out to only 15 psi over its maximum. That kind of force could easily be generated in a quick turn with the brakes on. If the tire blows off in such a scenario, then you'll be underneath the vehicle you were trying to avoid.

Go to your LBS, and explain that you want a tighter tire. They should know which tires are tighter. Don't let them argue with you, this is about the safety of your life.

(While tires and rims are supposed to be a nominal size, some are slightly larger and some are slightly smaller. Having a large tire on a small rim makes changing tires easier, but at great risk. Hence my advice to find a tighter tire).


Lots of chain slack... Time for a new chain? Bad derailluer?

It appears your rear derailleur pulley cage spring is not doing its job. In your picture, it should be pivoted back towards the right side of the picture, maintaining chain tension.

You'll have to remove and clean out your pulley cage, clean up and lubricate the spring and reassemble it. If that doesn't solve your problem, you'll have to replace the derailleur. You can see how to service many brands here: http://www.parktool.com/blog/repair-help/rear-derailleur-overhaul


Switch to a larger sprocket on child bike with coaster brakes

You should only need to replace the sprocket, nothing else. If you put on a smaller sprocket to get higher gearing/slower pedalling you need a smaller sprocket, not a larger one. You may need to remove a chain link.

Those parts should be standard, the same as on an adult bike, and any bike shop should be able to make the switch. Coaster brakes are common in Europe on adult commuter bikes and in the US on "beach cruiser" type bikes.

You're looking at a cog like this:

Which is about $7 on Amazon, so probably $10 or so from a bike shop, plus labour. You could swap it yourself if you're a little confident - just take the wheel off, use a screwdriver to pop the lock ring, swap the cog and put the lockring back (beware: the lockring is a spring and likely to go flying). With an o-ring plier they're easy enough to reinstall or you can use a couple of screwdrivers to push it on. The only hiccup might be if you need to remove a chain link to get it to work, in which case you will need a chain tool as well.

The main issue is 15-20 minutes of the mechanics time, which will cost you. It will be cheaper if you pop the wheel off before taking it in, or at least make sure it's easy to do so (but if that's tricky you probably want the mechanic to do it all anyway).


Shows some wear, but looks OK.

All teeth look symmetrical and so do the spaces between them. Really worn teeth look like a swept back shark dorsal fin or develop a visible burr.

Do a Google image search for 'worn chainring teeth' and you'll get plenty of examples.


Hard to provide an answer based on a picture but I would not commute to work on a wheel like that. If I had a light trail by my house I'd risk a slow ride or two to see how things hold up. But I'd be looking for a replacement wheel (not so easy now that COVID has messed up everyone's supply chains). Also check that the wheel wasn't bent out of true (center).
I'd wager your brakes don't work quite right when they clamp down on that dent. Over time the dent would likely accumulate grime from the road and from your break pads. Then you're in for uneven brake wear on one brake track and pad.  So long term I don't think you can count on using that wheel.


What PSI for downhill bike tires used for road biking?

You will have lower rolling resistance at a higher pressure

A lower pressure puts more tire in contact with the ground for traction.
In the dirt this can be important.

But you are running on the street.
Yes traction on the street is also important.
But your downhill tires are not going to have good traction on the street.

Downhill bike and downhill tires on the street you are looking for low rolling resistance.
So pump them up to the max and no hair pin turns at 20 mph.

If you are going to ride on the street you could mount some street type tires.
And they have tires for a mix of dirt and street.

This is probably a duplicate some where.
I did not search.


Selecting a drivetrain for touring bicycle

As other posters already mentioned: Rohloff seems the way to go...Super reliable and sturdy, but: hard to service for yourself "on the road".

On the other hand: if you have a Shimano (most common) 9 or 10 speed Deore XT drivetrain, it will also be hard to find (and thus service) spares in the middle of Africa..:)

If cost is no subject: forget the Surly (albeit a nice platform), and go for a rim-brake Pinion bike.
Why?:
Super reliable, more then enough spread in gears, it enables you to switch wheels (obviously not possible with Rohloff without losing your gears..) and the rim brakes don't make it a pain in the A@% when your wheel is broken and you want to use an alternative..

Maybe not the straight forward answer you were looking for, but if "the Ultimate touring bike" is required this might be the ticket!


Which derailleur should I use with a Shimano 7 speed freewheel 14-34T megarange?

This one.

Or this one. Or any 7 or 8 speed Mega Range rear derailleur from Shimano.

This issue can also be an adjustment of the B tension screw on your existing derailleur.


Bearing adjustment is part science and part art. It is based on a sense of feel from trial and error. It should feel smooth when spun, with the least amount of play. If it feels rough it is too tight or dirty. I had the most difficulty with tightening the jam nut after I made the adjustment. It seemed that the cone always got too tight while I was locking everything in place. You may find it easier to have a helper hold a wrench on one side while you hold the other cone and tighten the jam nut.


Are there sirens/horns that are like a car horn?

Here are a few loud horns:

The hornit:
A shop I used to work at sold these and they are extremely loud - around 140 decibels, but they sound like a loud beep rather than a horn. It takes 2 AAA batteries. Costs $45 US. The nice thing about this one is the button to press is remote, so you can have the horn on your fork or wherever.

Airzound: http://deltacycle.com/airzound-horn
This one is slightly less loud (115 db), but it has more of a honk to it and requires no batteries - it takes air pressure through your standard bike pump, so there's virtually no cost beyond the initial investment. this one is slightly bulkier as you have the horn itself, the air cannister, which looks like a water bottle, and the tube that connects them. A friend of mine has one and he says it's pretty effective.

There's also this kickstarter: https://www.kickstarter.com/projects/lansey/loud-bicycle-car-horns-for-cyclists
I've never seen this one in person, but the kickstarter can explain it for you. It has 112 db sound and sound the most like a car horn. it's $95 US though.

GaryE also showed this one:

  I use a bike horm from another Kickstarter project. It has a friendly sound and a very loud
  beep: ORP Smart Horn –  Gary E

The loudness is 98 db, but this one also has a light included


The front mounting straps on standard luggage racks are meant to be bent as needed to fit the bike.  It appears that bending them down just slightly and sliding them back in their slots should produce a nice alignment of the rack.


The pump needle broke off, leaving the base in the nozzle. How to remove the stuck base?

I just had this same thing happen last week. I straightened out a paper clip and bent a small hook in the end. Put the hook through the small hole in the center of the needle base and pull up. It came out pretty easily. Make sure you release the tension on the pump head first.


Why are some chainrings specs appended with an 'a' or 's'

From this article:

Type B: by far the most popular one and also the default on Ultegra
cranksets; it comes in 52 and 53 teeth and must be paired with 39
tooth inner chainring.
Type A: comes in 53 as well as 54 and 55 teeth; as per Shimano’s
advice must be installed together with a 42 small ring.
Type E: a VERY rare combination: 56/44

There is NOTHING unusual about the 39, 42, and 44 tooth chainrings. It is the outer big ring that has special gates and pins machined into it for smooth and fast shifting. Since the 53/39 cranksets are dime and a dozen, flatlanders and time-trialists alike may opt for a 42 inner ring for tighter gearing. The more inquisitive like myself are aware of the A and B type Shimano story so we go on Google and search if it is possible to mix and match. And what do you know, the internet says it is, so it has to be true!

As for the 'S', Shimano is Japanese and using an S is very common from Japanese manufacturers to denote a newer or Superior product. Nikon does this with their cameras, Shimano does it with chainrings and component updates, and so on. Shimano has also used S to denote a product is a sprocket/cog and many other manufacturers- some Japanese, some not- use an S to mean single speed.


If I understand the description of the issue properly: the chain hangs on the cassette sprockets slightly at the approx. 12 o'clock position where it should be peeling off to go to the chainrings, then 'pops' as it lets go.

In other words, you have slight chainsuck on some teeth of some cassette sprockets.

If there is a slight manufacturing defects or burrs on some cassette sprocket teeth that is catching the chain, those are probably going to wear off pretty quickly. I'd try to put a few miles on the bike and see if the problem resolves itself.

Something else you should probably check for are stiff joints between links in the chain. Again, some running-in wear on the drivetrain may resolve chain problems.


you need to know the width of the front fork at the axle, to know what width your new hub needs to be. Then you need the diameter of the wheel (mostly stated on the tire, 26" or 28" usually) and if you need a wheel with a braking surface on the rim of the wheel (if you have v-brakes: yes). If you have a disc brake in the front, you need a compatible hub for this. With those four things in mind you can go and look for a wheel :)


Mating Brifters and MTB drive train and disc brakes - Marriage or Divorce

You will need to buy a complete groupset. The SRAM 1x drivetrains have an optimized geometry where the upper pulley is moved slightly to the back. Furthermore the 1x drivetrains from SRAM can't compensate for the chain movement to the side caused by a shift with the deraileur.

As you can see in the links the Rival 1x deraileur is completly different to the Rival 22 deraileur.
https://www.sram.com/de/sram/road/products/sram-rival-1-rear-derailleur
https://www.sram.com/de/sram/road/products/sram-rival-22-schaltwerk-wifli-mit-mittlerem-k-fig

I think even the shifters need to be changed as I am not sure if the use the same pull ratio. The 1x road drivetrains are derived from the MTB stuff.


So you broke the 24T cog in the middle of the cassette? If that is the case i don't think it will be repairable. You may check with Sram Warranty though dependent on circumstance. I have had good luck with their warranty program in the past.

My reasoning for saying that it is not repairable is that on the XX1 cassettes,  the cluster is machined from one solid piece, except for the largest cog which is made from alloy rather than steel So they are not all independent cogs, but rather one large intricately machined piece, making single cog replacement impossible unless it is the largest cog.

From Bike Radar:

  Many of the lessons learned from developing the Red and XX cassettes were applied to XX1. 10 of the 11 cogs are machined from a single block of tool steel. Manufacturing begins with a bell-shaped forged blank. This blank is placed onto a lathe that removes a significant chunk of material and leaves the blank with a stair step profile. Next, a CNC machine removes more material by carving the teeth, shift ramps and the 16 pins that are used to secure the 42-tooth aluminum cog to the steel cassette body.

From Pink Bike


Rear derailleur movement where it is bolted to hanger

I think you cannot do anything with this wobble. I have similar one, opened the derailleur, but inside I just found out that the part that goes around that bolt inside is probably slightly deformed. It is a metallic cylinder - a hole that goes around the bolt, but when it becomes deformed to be slightly wider, it just causes some play of the derailleur on the hanger.
You can test whether my description fits your situation by wiggling the derailleur and looking what actually moves. In my case the bolt and the flat metallic part connected to it stay firmly connected to the hanger and what moves is the actual body of the derailleur (painted).


campagnolo wheel on shimano or sram drivetrain?

I don't have experience with that exact setup. I have used a Shimano-9 wheel on a Campy-9 drivetrain, and it more or less works. With the addition of a shiftmate, you can mechanically compensate for the differences in cable pull. It's a little fussy getting set up right, but it does work.

Also, (not that you asked, just in case someone else finds this thread in the future), Mavic sells a cassette that fits Shimano splines but has Campy-10 spacing, for use on a Campy drivetrain. I'm not aware of a cassette that does the reverse, but it wouldn't surprise me if one is out there.


Podium girls: when did they first appear?

"As soon as cycling races started" is probably one way of answering your question "when and where the first podium girls appeared at a cycling race?"
I had a look at Greek art related to sports. A lot of it shows women which seem to meet the Greek ethos of female beauty. On that basis I would argue the idea of attractive women accompanying male sports winners is as old as sport. It is unlikely the first presence of a podium girl at a cycling race is documented, but I think it is safe to assume they were pretty much always there.
I know it was goddess Nike and not just a civilian, and I'm sorry if you were after a specific event name, date and location but hopefully you can see this as one way of answering your question.
If you were after the oldest specific, traceable record/mention of a podium girl at a cycling race, then you may want to reword your question.
Examples below - possibly NSFW.
From this

From this

From this

From this


The RD-M786-SGS is rated for a big sprocket of max 36T, so if you want to follow strictly Shimano specs, no.
That being said, Shimano has high standards and is very conservative, so it is possible that it works. I personally just installed on my bike a Microshift 9sp 11-42T cassette (no goatlink) on an Acera RD-M3000, rated for 36T max (I had to adjust the B-screw). If you want to do things properly, you may also need to add some links to the chain, especially in a 1x setup. I have a 2x (46/30), I've let the chain as is and try to avoid even more the big chainring/big sprocket combination — I was also fearing that adding some links would cause the chain to swing too much on rough surfaces.
It seems to work well so far, but I haven't tested extensively in rough terrains. That being said, I tried because I have found several comments of other persons saying they have installed successfully this cassette on derailleurs rated for 36T max (including some old Deore and XTs).
I would assume a similar reasoning is also valid in your case.


With most of them the trick is you only unfasten the adapter to get the wheel off, not the caliper itself. The adapter doesn't have any range of adjustment in how it mounts to the fork, so it can be removed and re-installed without disrupting the adjustment.

There may be a post mount only Lefty out there. If so, the difficulty you're having is basically unavoidable.

It's also important to get a pad spacer in there when the wheel is off.

Edit in reply to comment:

So, you have the XTR brakes, I believe BR-M975, that represent one of very few disc brakes ever made that connect directly to IS tabs without any kind of adapter. There aren't many brakes like this and dealing with this design involves some steps that won't be covered in generic instructions about adjusting disc brakes. This design can only be adjusted for alignment by adding and taking away micro shims between the caliper and the fork. It's a little cruel and unusual that you wound up with the combination of this brake on a Lefty, because it creates hoops to jump through that would be troublesome for anyone. The good news is that once you get the shim configuration figured out that results in good alignment, you can keep the shims there on the bolts while the wheel is off and it shouldn't require readjustment when you put the wheel back on.

Such shims can be ordered online or bought from any good shop. There are two types; one (Shimano) is open and has two prongs, the other is like a really thin (0.1mm) washer. You want the washer type because the other one will want to fall off whenever you go to remove the wheel. With the washer type, just screw the caliper mounting bolts back in to the fork a few turns once the wheel is off, down to the loctite.

The goal of the design is that with fresh pads, properly faced tabs, and everything to spec as per the IS standard, the caliper can be bolted to the frame and everything is perfectly aligned without any adjustment at all. This may or may not be achievable on any given fork or hub, depending on exact adherence to the IS spec in terms of lateral position of the IS tabs and the rotor mounting surface on the hub.


Brand new single speed bike has a skip in the free wheel motion or make a click noise once every rotation of the tire

After a month the the freewheel did not improve so I bought and installed a new Shimano freewheel.  The results were night and day.  Gone was the knock when pedaling and the warble of the back tire was gone as well.

The OEM freewheel was like dog excrement and the new Shimano is like pedaling on butter.


Replaced tyre and tube, now the rear gears will not stop

Sounds like you have not put the wheel back in properly and have somehow managed to over-tighten the freewheel/freehub, causing it not to spin freely.

You will have to take the wheel out and check that the axle nuts are done up properly and that the freewheel/freehub works. At a guess you are not using a quick-release lever, with nut-style axles you must tighten up each side gradually - 1/2 a turn each side once the wheel is in place or else you can tighten the axle (instead of putting the wheel in).

Do check for 'play' in the wheel once it is back in, if there is any then you will need to get it adjusted - wheel back out time... If you cannot work out what is going on with it, visit a friendly LBS during a quiet weekday to see if they can put it right for you whilst-you-wait.


How can I develop my abs while I ride my bicycle?

Since cycling doesn't put your abs through a large range of motion, you're not likely to develop your abs by only biking to work. However, depending on how in shape you are, you will probably notice that your overall fitness level increases.


Crank sliding horizontally through the bottom bracket

You need a large allen key, often an 8mm to tighten that centre bolt right down.

It'll pull the crank arm onto the spindle and secure it.

The LH-FSA-AL ring is the self extracting bolt, the internal hex bolt pushes on the back of it to pull the crank off without extra tools. That has a left hand thread so that it doesn't unscrew as the internal bolt unscrews. It only really needs to be tight enough to stop it from coming out, finger tight probably isn't enough though.

You need a pin spanner for this which is a pretty specialised tool, I've certainly never had need to buy one, so you might want to pop down your LBS and ask them to tighten it up.


Do new wheels usually come with freehubs?

Wheels that take a cassette (Road, Mountain Bike, etc) generally come with a freewheel hub. Generally these are Shimano/SRAM compatible or Campy compatible. If it doesn't say, you can just about bet on Shimano/SRAM compat.

The wheelset you linked to does and is Shimano/SRAM compat.

Wheels for fixies/tracks/single speeds usually do not have a freewheel sprocket (or a fixed cog). If it doesn't say, chances are it's not included.


There's been a problem in your situation with preloading the bearings is my guess.  Based on the external bearing cup and a glimpse at the end of the video of your left crank arm, it appears you have a SRAM crankset installed? This video from SRAM, notes that insufficient preload of the bearings before full torque is reached may result in lateral play of the crankset.  This is shown around the 3:30 mark of the video.  While this video features a non-BBright  bottom bracket shell, the similar problem to yours is fairly meaningful and if not the exact reason or answer for your case, I think it'll be along those lines.

The other video that's linked at the end of this paragraph features BBright bottom bracket and compatible FSA crankset install. Significant here is that with this particular crankset and others that mate to the BBright system, bearing seals and wave washers need to be placed and a fair amount of torque--around 45-50 N-m--is required for the fixing bolt.  Missing the washer placement or less than adequate torque will lead to symptoms such as yours.
BBright bottom bracket and FSA crank install

If a LBS did the BB install, it's best to return the bike to the shop and discuss it with them.  The rework should incur no additional cost (IMHO).


Tires that are 27 x anything all have a bead seat diameter of 630 mm, so they should fit on the rim as the tire diameter is the same.  (Assuming of course your current tires (27 1 1/4) fit correctly). That leaves the following questions:

Are your rim width wide enough for the wider tire?
Does your frame have sufficient clearance
If you have fenders, do your fenders have sufficient clearance.

The widths of the two sizes in question are 32 mm  and 35 mm respectively, which is a small change in width, so it is likely that if again if your current tires (27 1 1/4 tires) currently fit correctly, the slightly wider tires should be fine.

Finally, whether or not the Kenda K161 are appropriate depends on what you mean as "slippery".  If "slippery" means wet, then the tire compound matters most (bicycle tires are too narrow to hydroplane), look for soft tacky rubber. If "slippery" means compacted snow, then the lug pattern (see below) could help.  If "slippery" means black ice, few if any tires will be sufficient (maybe the Continental Top Winter Contact, but I have never used them). If "slippery" is actual ice, then studded tires are best.

Kenda K161


Are there any post 2013 studies available that focus on the use of bike lights during the day to prevent collisions with cars?

No. Such studies are rarely done, and it would be difficult to get ethical approval for another one as the benefits have been clearly established. This would mean asking the people not using lights to put their lives at risk merely to reproduce other studies. Even if such approval could be obtained, I think the study should not be undertaken for that reason.

See this existing question for links to the previous studies.

Edit: since people seem to be struggling to understand the question and my answer:

the question was specifically "recent studies", hence the "no" answer.
The ethics of the study might vary between social science and medicine/engineering, but in the latter you cannot generally ask or permit people to take a dangerous action, no matter how interesting it might be. A study comparing, say, constant with flashing lights is more likely to get ethical approval than one which asks people not to use lights, or just dumps them from the study if they do. Some social scientists (eg, economists) have less restrictive ethical rules.
the difference is between passively observing that many cyclists ride without daytime lights, and asking people to refrain from using lights during the day. The latter requires explicitly saying "this is dangerous, please do it", and that is where ethical problems arise.

Imagine the question is, say "is smoking dangerous", or "is being obese dangerous" now. You can't really ask people to take up smoking or become obese (alternatively, that request is unlikely to get ethical approval), and you have to carefully design the study to allow for people who stop being eligible during the study. But, importantly, when you're comparing a fix (a quit smoking program, or a diet change), you need to come up with a control intervention that reveals the (dis)benefit of the chosen intervention without further harming the participants. Normal practice is to compare the intervention under study to the current best practice intervention rather than to nothing. There is even a meta-study of how often trials are stopped early for benefit when it becomes obvious that the trial intervention is significantly better than the comparison.

So for "cyclists using lights during the day" questions, a comparison of best practice (constant daylight lights) to a plausible alternative (flashing lights) is more likely to be approved than one where the alternative is the known-dangerous, definitely not best practice "no lights".


How to fix tubeless tire leak at rim seam

The fix ended up being very simple. After inflating the tire to 30 psi to seat it, I decreased the psi to 15 and rolled the tires like normal over the next couple hours.  Then I dropped the psi down to my running pressure of 5 psi.

The problem simply seemed to be that 30 psi was too high while the sealant was sealing the gaps.  15 psi seemed high enough to push it into the gaps and low enough to let it seal.


Campagnolo Ergopower inaccurate shifting on high and low cogs

The problem is that you have the cable incorrectly routed under the pinch bolt / washer.

You need to route the cable down the same "side" of the pinch bolt, but the washer needs to turn 90 degrees clockwise, so that one "claw" sits in the hole in the derailleur body, one "claw" sits outside the derailleur body next to the free end of the cable and the cable itself should be trapped, in a straight line, under the small extended flange on the washer that has a groove cut in it, for that purpose.

You might need to use a new cable as the way you have it clamped, it's forced a "kink" into it which will probably not straighten out fully and so will always affect the cable tension, slightly, so giving you inaccurate shifting.


Can I remove my thru axle when the lever is disengaged?

Because necessity is the mother of solving problems caused by poorly designed components, I'm answering my own question.
I tried vice grips, as someone recommended, but the alloy in the axle was too soft to get any bite before they slipped off (did manage to mangle the exposed threads though, so that was fun to file off before removing it).
The solution that ended up working was to jam (force) a ball-end hex wrench that was just too big into the open end of the axle, press hard, and turn. For this axle it was a 3/16" (4mm was too small, 5mm was too big). As soon as I got it backed off just a hair the lever engaged as it should, and all was right with the world.
For reference, I also tried this approach using various sizes of Philip's head screwdriver without success. My next plan was to file a slot in the threaded end for my jumbo sized flat head screwdriver. If that didn't work, I was going to buy a reverse-treaded screw extractor. Based on my experience, either of those approaches should have worked as well.
I'm fairly confident that if I had taken this approach from the start I could have salvage the axle (at least until my new one comes in the mail). Live and learn.


Is there an improvement braking from the hoods from Shimano Sora 3500 to Sora R3000?

The R3000 levers have the shifting cables routed under the bar tape as opposed to coming out the sides on the older 3500 levers. If you care for the esthetics then that might be another reason to upgrade.  I'm not sure if the  braking performance actually changed as I don't have older Sora to compare to, but the R3000 levers in my experience seem to offer good braking performance from the hoods. The design of the R3000 levers is similar to the other higher tier models (tiagra, 105, etc) so I assume that the braking performance would be the same as those, assuming the brakes at the other end of the cables were also of the same quality.


Triple chainring + nonstandard sloped cogset. Can this work?

Yes, you could do this and done as you describe I think you'd end up with as many ratios as rear cogs.

Someone once made a single-shifter derailleur system that moved both derailleurs from one shifter (using two cables) and "IXOV" has apparently started doing that again with the "Synchrobox" but all I can find are press releases, not even a company website. They typically use fewer than the maximum number of gears because of the overlaps, but from memory they do give more than just one gear per rear cog.

If you were building a bike this way you might be able to get away with minor back-jumps (a cassette that went 12,13,14,15,13,18,21, say). You might even be able do use a normal shifter with it by using a lever attached to the cable to shift the front derailleur some fraction of the movement of the rear one, but I suspect that would not work very well. If you used a cam instead you could get the larger movements for chainring shifts where you wanted them, but it would be a more complex design.

Using that diagram above to help me think, if you had a 9 speed close ratio road cassette you'd have three gears per chainring:

chainring / cog = ratio

9 speed 12-23            10 speed 12-30

44 / 12   =  3.67        44 / 12   =  3.67
44 / 13   =  3.38        44 / 13   =  3.38
44 / 14   =  3.14        44 / 14   =  3.14
34 / 15   =  2.27        34 / 15   =  2.27
34 / 16   =  2.13        34 / 17   =  2.00
34 / 17   =  2.00        34 / 19   =  1.79
24 / 19   =  1.26        24 / 21   =  1.14
24 / 21   =  1.14        24 / 24   =  1.00
24 / 23   =  1.04        24 / 27   =  0.89
                         24 / 30   =  0.80

That doesn't work too badly, graphed it looks like this:

With a 10 speed 12-30 cassette that also works:


Personally, if your road frame is an out-and-out road bike - I would say you will be faced with several issues.

strength of your frame

Not only will this stress your frame - it may also fatigue the frame. And may cause sudden and catastrophic failure.

tyre clearance

Most road frames will not take a tyre greater than 28mm. Some no more than 25mm.

comfort

The seating position and reach could be altered to make more comfortable - but it will always be a compromise.

Geometry

Road bikes have different geometry to CX bikes. Lower bottom bracket offers lower clearance, steeper head angle makes the ride more twitchy.


This will run in python (only 3.X, not 2.7), a free to install programming language. Simply save the following as a file ending .py - e.g. timetrials.py. Then open IDLE3 (start menu), and open the file (Ctrl+O). Finally, press F5 to start it.

import datetime
from operator import itemgetter

def get_int_input(prompt, min_=0, max_=None):
    """Get a valid integer input."""
    while True:
        try:
            i = int(input(prompt))
        except ValueError:
            print("Please enter an integer.")
        else:
            if min_ is not None and i < min_:
                print("Must be at least {0}.".format(min_))
                continue
            elif max_ is not None and i > max_:
                print("Must be at most {0}.".format(max_))
                continue
            return i

def get_time():
    """"Get a time input as a datetime.time object."""
    h = get_int_input("Hours (0-23): ", max_=23)
    m = get_int_input("Minutes (0-59): ", max_=59)
    s = get_int_input("Seconds (0-59): ", max_=59)
    ms = get_int_input("Milliseconds (0-999): ", max_=999)
    return datetime.time(h, m, s, ms*1000)

def get_results(competitors):
    """Get a dict of finishing times for all competitors."""
    results = {}
    for _ in range(competitors):
        while True:
            competitor = get_int_input("Enter competitor number: ", min_=1, max_=competitors+1)
            if competitor not in results:
                results[competitor] = get_time()
                break
            print("Time already entered.")
        print_results(results)
    return results

def print_results(results):
    """Display the race results in a table, fastest first."""
    linet = '┌' + "─" * 12 + '┬' + '─' * 17 + '┐'
    linec = '├' + "─" * 12 + '┼' + '─' * 17 + '┤'
    lineb = '└' + "─" * 12 + '┴' + '─' * 17 + '┘'
    print(linet)
    print("│ Competitor │ Time (H:M:S)    │")
    for n, t in sorted(results.items(), key=itemgetter(1)):
        print(linec)
        print("│ {0:<10d} │ {1!s:<15} │".format(n, t))
    print(lineb)

def race():
    """Handle race times for a user-specified number of competitors."""
    n = get_int_input("Enter number of competitors (2-): ", min_=2)
    results = get_results(n)

if __name__ == "__main__":
    race()

When everyone has finished, it will look something like this:

┌──────────────┬───────────────┐
│  Con Num     │ Time H:M:S    │
├──────────────┼───────────────┤
│  1           │ 5:4:3.2       │
├──────────────┼───────────────┤
│  2           │ 8:7:6.5       │
├──────────────┼───────────────┤
│  3           │ 2:2:2.2       │
└──────────────┴───────────────┘


A few simple tips:

Whether it's cycling, running or any other physical activity the more gradually you build up your mileage, the better off you'll be in the long run. A good rule of thumb is don't increase your time or mileage by more than 10% a week.
Carrying on a conversation with someone should be difficult but not impossible. If you can't carry on a conversation you're probably pushing too hard.
Consistency trumps volume. 3-4 short rides a week will do more for your overall fitness than 1-2 longer riders each week.
We can not get grace from gadgets. It's easy to get sucked into buying ever newer, shinier and lighter parts. However, if you think these things make a big difference you're fooling yourself. Keep in mind when you're pedaling up a hill you're not just pedaling a 14 or 20 or 25 pound bike. You're also carrying your weight and the weight of anything you have with you (such as water bottles). When you look at a combined bike and rider weight of 170 pounds or more suddenly saving 30 or 50 grams is a minuscule difference. I've wrenched for several professional racers and trust me, most of them couldn't care less about their bikes.
Do invest in cycling shoes and clothes if you're going to do longer rides. Cycling shorts - whether the baggy style or the lycra type - are designed to reduce friction. Cycling shoes with clipless pedals are more efficient and also safer (once you get used them - which takes some practice).
Don't forget to drink. It's easier to get dehydrated while riding than in most other activities. You're moving faster so the sweat evaporates faster and that fools you into thinking you're not sweating that much.
Enjoy riding. I've seen people who bail on a ride because they couldn't get Strava to work. That's insane. Ride because you want. You're not a pro, your paycheck doesn't depend on how fast and how often you ride.


Why Do I Need a Better/Lighter Road Bicycle to Train For 'Fitness'?

Rob, you are correct that a heavier bike will give you a greater fitness benefit over the same distance.

The only real counter-point I have is that the most effective bikes for fitness are the ones that get ridden. So, if some reason a lighter bike would more fun or appealing to you (while still be a "good enough" commuter), than a lighter bike could be a better choice for you.

In my experience, extra weight is not noticed much for commuting, so I'd rather have the durability of CroMoly over aluminum or carbon, and the practical benefits of fenders, racks, lights and bags.

An anecdote: My wife rides a bike with electric assist. You might think electric assist would reduce the fitness benefit, but opposite is true for her. She takes more trips because she has electric assist (including carrying one or two children plus cargo), and thus ends up riding-- and pedaling-- more than if she had an unassisted bike.

Some will suggest that you should get a lighter bike for "social" riding. That depends on who you ride with and what their fitness levels and interests are. I'm personally a stronger rider, and prefer to ride with my wife, parents and older friends, as well my children. For me, having a bike that's a bit heavier improves the social parity and helps to me ride naturally closer to the same speed with the people I prefer to ride with. If you want a hang with "Group A" club rides, lighter would be way the go instead.

Whatever gets you out riding the most is best bike for you.


Non U-Lock that can be mounted for carrying?

Any specific lock recommendation is going to be out of date in a year, so I'll focus on identifying the best kind of lock:

Any cable locks are going to be insecure by nature, but it's unfortunately the only other kind of lock available just now. (I'm not counting big-ass chains with giant locks; those are more for show than for security.)

One of the heavier Kryptonite cable locks is probably your best bet. To beef up the security, I'd get two of them and lock up different parts of the bike. I'm told that keyed locks are harder to crack than combination locks.

However, have you considered getting a smaller U-lock and a long cable? You'd get the best of both worlds that way. Since places to lock up are scarce, you'd usually end up using it as just a cable lock, but it'd give you flexibility in the event you find a good sign or bike rack.

Bike mounts: These tend to fall apart rather quickly. I recommend focusing on a small pag to carry your locks, rather than use a frame mount. There are triangle frame bags and small trunk bags that do the job nicely. However, cable locks have a great advantage over U-locks--you can coil them up and hang them from your handlebars. Unless you have smaller drop bars, it's amazingly convenient.


There are a few studies which show that lower pedaling rate is more efficient (i.e. consumes less oxygen/fuel for the same power output):
1, 2, 3
However, it stands to reason that it’s more tiring for your muscles because they have to produce more force/torque to achieve the same power output.
I think your body is pretty good at picking the right cadence for the current circumstances. Most cyclists automatically pedal at around 90rpm when riding at moderate or high intensity. That being said, I think it can still make sense to train at very low or high cadence from time to time. It’s also a good idea to have the right gear range and gear steps for the terrain you are riding.


If the lever is hard but there is no stopping power, two things it could be (there may be more of course):

Brake fluid was spilled on the brake pads/rotor when bleeding. This is pretty easy to do if you dont take the pads out when bleeding. If you bled them again yourself for the first time you may have done this again (which could be why they are now worse).  Check the brake pads and rotor to see if the have fluid on them. If so it is easiest to clean the rotor and get new brake pads. (This happened to me last week) some people clean the brake pads in an oven but that seems tedious.
Brake pads need to be broken in before they work very well. My guess is that your front brakes could have used thise before you bled them. Easiest way is to get up to high speed and lightly hold the brake for a while the press if hard until you stop. If you have a long hill nearby you could do this there. Or just on the street in front of your house.

And If the o ring near on you bleed screw is busted you should replace that


Essentially you have one of these:

This is an older type of saddle clamp that was popular when seat posts were made from steel rather than alloy. Any saddle bought from a bike shop will fit. The general idea is that the bolt goes behind instead of in front of the post, you tighten it up on both sides so that the top of the seat is level and the seat is centered on the rails. Swapping over a seat can be a 'bit of a fiddle' as there isn't necessarily a lot of room under the seat to assemble all the bits and keep them in place whilst you do up the bolt.

As for saddle choice, you don't have to worry about weight, the elements or the seat getting damaged from being in accidents etc. Therefore you should be able to choose from the heavier/more comfortable seats to find something in budget.


You might want to play around with Bike Calculator a little, and you could find a reasonable estimate for your question.

Regarding the new bike purchase, shop around carefully. You're already past what is considered the clearance season for 2012 models at many traditional brick-and-mortar bicycle retailers. Prime time is August/September of each year. That's when many retailers start their clearance sales.


What shifters are compatible with shimano 9-speed?

According to the Wikipedia page, the following groupset variations were specifically 9-speed:

Dura-Ace 7700 (1996-2002)
Ultegra 6500 (1997-2004)
105 5500 (dates unknown)
Tiagra before 4600 (before 2011)
Sora 3400 (2012-)

As far as other components go, it seems that as long as the cassette, chain and shifters match then the groupset should work. All Shimano rear derailleurs (excluding early Dura-Ace) have the same shift ratio, so they should work so long as the derailleur has enough travel capacity - use one rated for the same or higher number of gears than in your cassette.


Chain skip happening seemingly at random with a new chain

Pedaling while changing gears in important to avoid damage to derailleur and chain.  Gear shifting proper technique by Sheldon Brown.
Shift the gears so that chain is on the middle chain ring(at the pedals) and approximately on the middle gear on the cassette. Verify that the derailer with the chain is vertical, if not adjust accordingly.
Also, it is possible that chain may be skipping if the derailleur is slightly bent - in this case bring your bike in to a reputed local bike shop(LBS) and have it checked out. It may save your derailleur from further damage and possible need to replace it.
Changing to an easier gear just before you climb and spinning pedals (lower effort but slightly higher pedal cadence), instead of mashing on a tougher gear (applying greater force and lower pedal cadence) helps avoid chain skipping.


What are the most basic parts of a bicycle which cannot be upgraded over a period of time?

Certain parts of a bicycle are more easily upgradeable than others, while other types of upgrades require special tools, much more money investments or are limited to whatever standards are used in its design. For some parts, the opportunity of an upgrade coincides with the older part being worn out; in other cases, the replacement is not warranted by this fact.
Let's go from the easiest replacement to the hardest ones. I'll organize them in tiers.

Non-essential stuff that does not affect key function of a bicycle: lights, bells, fenders, phone holders, cycling computers etc. These can be replaced very cheaply and easily.

Contact points: pedals, handlebar grips/tape, saddle. These parts are often a part of one's personal preferences and get swapped immediately after a purchase of a new bike. Many bikes are sold without pedals for this reason, and some people argue the same should apply to saddles and grips.

Regular wear and tear items: chain, tires, tubes, brake pads, cables, bottom brackets. One can upgrade to a lighter chain when replacing a worn one. Tires are often subject to personal preferences the same way as pedals are. One can prefer lighter or sturdier, narrower or wider, smoother or knobbier, all black or tan wall etc. tires depending on what and how they ride. On tubes, one can buy lighter or sturdier ones, or even go tubeless as an upgrade. The same applies to pads and cables: there are aftermarket products which are better in performance/longevity.

Hard wear and tear items: cassettes and chainrings, braking discs. It takes more time, but ultimately, these parts wear out and are bound to be replaced/upgraded. Here compatibility issues are becoming more prominent (even though they already play role in the earlier tiers), and not everything is clearly compatible with everything else. Some parts are likely to be of limited availability. As an example, replacing an 8-speed cassette with 11-speed might bring you to the next tier of costs/troubles, as it will drag everything drivetrain-related with it.

Non-wear components that are at higher risk of breaking: derailleurs, brake calipers and levers, shifters, wheels. Normally these parts do not get worn per se, but they run higher risks of being damaged in minor crashes. Replacement options are often limited by the bicycle design. E.g.: there is no easy way to switch from QR-skewers to through axle hubs unless the frame supports it. Similarly, no safe way to put disc brakes on rim-braked bike.

Non-wear components that are at low risk of breaking: handlebars, cranks, forks, frames, headsets, seatposts. Unless you have a specially nasty hard crash, these parts do not wear out. Replacing them is always justified by the owner's desire to "upgrade" something in any meaning of the word (even if that means changing the color). At this point, the compatibility is the main issue: there are dozens of seatpost diameters and lengths, a hundred of headset dimension combinations, many frame sizes and innumerable variations in geometry, several handlebar diameters and lengths etc. etc. Unless something is explicitly compatible in every aspect of its parameters, it is not.

The presented classification is not universal of course. Certain items can be moved up or down a bit. For example, wheels with rim brake surfaces are rather at level 3 (i.e., eventually worn out). For some people, bottom brackets live for years (thus being on tier 3 or 4), while others replace them every season (tier 2), and so on. I am likely to have forgotten a lot of essential parts as well.


There was an article in the CTC magazine recently about a guy who'd built one. Their website has a FAQ which might be of interest.

Details include:

Tyres/tubes from unicycles
Needed very large disk rotors to make it stop 203mm.
Claimed to fit people of 5ft 3in to 6ft 5in (yes, I was surprised).

Also, I've spotted an example here which looks a lot like the picture in the magazine.