Does fitting mudguards / fenders improve aerodynamics?

It complex.

The aerodynamics of a bicycle and rider through the air at the speeds involved in cycling mean the factors which determine drag are primarily:

the size of the bike + rider,
the shape the bike + rider presents
to the air flow, and
to a smaller degree, the texture of the surface
of the bike + rider.

Size

Size is pretty straightforward, a larger object (as determined by frontal surface area as presented to the air flow) of the shame shape and surface texture and relative air speeds has greater drag, and the increase in drag will be in proportion to the increase in size.

So one method of reducing drag is to make the bike + rider smaller. Riders do this by using narrower wheels, tyres and components, and most notably by changing their position on a bike, with the most obvious example being riding a recumbent bicycle.

Obviously competitions of different types (UCI, triathlon and others) have rules which limit the scope of equipment and positional changes possible.

Adding a fairing or guard increases the size of the overall bike + rider, so on this basis it will increase drag, however as we shall see, whether it does in fact increase drag (or indeed reduces it) depends on its shape.

Shape

Shape presents a more complex set of interactions on aerodynamics. Air at these speeds does not "like" surprises, by that I mean objects that present rapid changes in the air flow such as sharp edges or angles on bluff bodies. These create a lot of turbulence in the air flow and this in turn creates a larger difference in the total pressure in front of and behind the object than when air is less disturbed as it flows around a smoother object. It's this pressure differential that largely (but not solely) determines the total drag.

You can reduce drag by creating a more streamlined shape, hence the development of deeper section wheels, streamlined shaped tubing and other components (handlebars, helmets etc). So even though an object's size might be larger, it can still present less overall drag because its shape is more streamlined. This is why speed record recumbents are fully faired with a long teardrop shape, and are a lot faster even though they are physically larger than the bike and rider they enclose.

Hence a fairing or guard has the potential to make drag better (or worse) depending upon its shape.

Surface texture

Finally, the surface roughness also plays a small role in aerodynamics of cyclists as this relates to what we call the surface frictional drag. The more aerodynamically shaped an object, the more this element comes into play. For cycling it's a minor (but not insignificant) component, one for which more attention is paid when size and shape have been optimised given the constraints in play (e.g. competition rules). Simple things like using tight fitting clothing (e.g. skin suits), or more sophisticated use of surface textures and air trips. We can expect that the surface texture of a fairing or guard would be relatively smooth to present minimal frictional drag, although there is potential for the use of strategically placed air trips.

Wind direction

All three of these factors are complicated by the fact that when cycling air does not always flow in the same relative, i.e. head on, direction but can flow around a bike + rider at a different angle to head on (e.g. when riding in cross winds). Aerodynamically this has the impact of changing the effective size, shape and surface roughness of the object presented normal to the airflow. So what was a better aero choice in head on conditions may now become a worse choice when the air flow is at an angle relative to the cyclist's direction of travel.

So, what's the answer?

I don't know. And neither does anyone else.

Guards and fairings add size but have the potential if well designed to present a more streamlined shape and reduce frictional drag. They also have the potential to make a shape less streamlined overall and to compound the additional drag presented by their increased size. Adding to the complexity is how they impact aerodynamics when the relative direction of air flow varies.

The only way to know is to measure drag using a wind tunnel and/or via validated field based aerodynamic testing methods, and/or by doing so virtually via computer modelling (use of Computational Fluid Dynamics techniques - CFD). When testing modest changes of equipment or position, it requires well honed methods and analysis techniques.

Once thing I have learned from performing aerodynamics testing is you can never really be sure what the outcome of such modest changes will be until you test. And retest to make sure.

Showing the results of one test, of one type of guard/fairing on one specific set up and rider only ever tells you the answer for that particular set up and rider. It is not an outcome which can be applied universally.


Note that you cannot swap wheels, since the front wheel has a different hub from the rear ones.  You could presumably swap tires, but there would be little point in this unless the front tire for some reason has a much thicker tread than the rear ones.

If the brakes are rubbing on the rim it may be that the rim is warped and needs to be "trued", or it may be that the brakes are out of adjustment somehow.  (Rim brakes can be tricky to adjust.)  It's also possible that the axle is simply not seated squarely in the notches of the fork.


Yes, you should definitely cut the head out when you get back to your house, and then patch the tire.   Whether you want to install a tube, instead of continuing to run tubeless.


How long should MTB disc brake pads last?

There are different types of pads, even to fit the same model of brakes.

Sintered metal pads last longest, but are noisiest, often to the point of not being worth the better durability.

Resin pads are softer, and will last less mileage, particularly in wetter weather, but still should last far longer than 100 miles.

I would say that the rotors are damaged from being ridden metal on metal before, and need to be replaced, along with new brake pads.

Your mileage will vary based on weather, braking habits, pad type, riding style and terrain. But you should normally get 500-700miles from a resin pad, and 1000-1250 miles from a sintered metal pad.


For 9 speed or below, SRAM sells the Powerlink, which is a reusable way of opening and closing a chain. You can open and close these a few times, at least for the life of a chain.

For 10 speed and above, SRAM sells the Powerlock, which is a one-time use way of closing a chain. It is not designed to be opened and closed, and it is not suggested that you re-use it.

Do people re-use Powerlocks? Sometimes. Do they get away with it? Fairly often. Do they come apart? Also reasonably often. Would I recommend it? Of course not -- they're cheap, just buy a new one each time. It's generally going to be worth the potential costs of dealing with chain failure when you're out riding.

If you want to use a quick link for a 10 speed+ chain thats able to be opened and closed repeatedly, try the KMC Missinglink for 10 speed chains or the Wipperman Connex link. Both are designed to be reusable. (*)

(*) Officially, chain manufacturers don't recommend mixing brand X's chain closing mechanism with brand Y's chain when X!=Y, but people have generally found it safe to mix quick links between manufacturers. So, with this in mind, I'd still recommend the KMC or Wipperman if you want to detach and reattach the chain repeatedly.


How do you check your road bike tires for wear?

If you're not getting regular punctures due to the thin-ness of the tire or the fabric of the tire is showing/damaged, you can keep the tires on (Sheldon). Unlike a car tire, a tubular tire just requires the tire portion to prevent the tube from getting cut up. And road tires should be smooth since you don't need tread.


There are several criteria when selecting a front derailleur. Top, bottom and now side cable pull. Some Shimano models are both top and bottom compatible. The mount type, seat post clamp mount (correct diameter or have an adapter), bottom bracket mount or direct mount. The derailleur must be compatible with your crankset size. This is usually specified by a maximum number of teeth. It must also match the number of ring gears on the crank (double or triple). It must also match the chain 8,9,10 etc, speed. There is some overlap on 7 and 8 speeds that will work with both.


How to adjust when i am 5'5 foot tall and having a 42 cm roadbike frame?

That sounds like an extremely small frame for you. In fact, it sounds like an extremely small frame, period—frames usually aren't sized that small.
Every manufacturer is going to have its own sizing guidelines, but in rough terms, I would expect someone of your height to ride a 52-cm frame.


What bottom bracket is this and why does it have a lockring?

It's probably a cup and cone bottom bracket with the splined tool interface rather than wrench flats or pin holes. Most recent ones are like this, I believe as a function of what tools now make up the standard arsenal at bike factories. Or it may be a cartridge BB with a lockring, which have existed but aren't common. In either case, you remove it by loosening the lockring and then removing the cups.


I divide between two extremes:

Riding long distance with lots of stuff on good pavement: load the bike;
Riding short distance with not so much stuff and/or on rough road: load the back;

Of course, there are some additional considerations:

If the road is so harsh you must stand up to manoeuver (off-road, back-country, XC, etc.), load yourself. The bike suffers less (tires specially), and you can avoid falling from lost control;
If you have lots of gear and proper tires, loading the bike help to ride more stable and comfortable, since the cushioning effect of the tires (suspension) is enhanced by the added bicycle mass;
If you ride short, loading back is much more pratical. But if you are touring, loading the back becomes a huge source of discomfort and even health problems.

Tire choice is important, also. On a skinny-tire road bike, I would not feel safe or comfortable to put a rear rack in nothing but the smoothest of paved roads. In the other hand, I have already made loaded touring in roads that looked like the moon surface. How much is too skinny, or fat enough, depends on each person/bicycle/road.

In the end, the answer is "it depends", but I think the three (four?) parameters mentioned here are the most important about "what" it depends on, IMO.

Hope it helps.


A 13 mm (or possibly a 15 mm)  socket should do the trick for removal.  You won't be able to budge the crank arms after removal of these.  For this you'll need a Crank puller.  One aspect of this tool threads into the center of the crank arms (not the same spot as the fastener you just removed but right around there).  Then a second bolt tool with a special head threads into the first part, pushes on the spindle of the bottom bracket which affects the movement of the crankarm off the spindle.

Here's a link to a Crank puller.
Here's a couple "for instance" chainsets that are around the level of your current one:
Shimano Tourney,   SRAM
Should you choose to remove and change your bottom bracket, which the specs for your bike state is a Shimano cartridge-type BB-UN26, you will need a bottom-bracket tool.

Cartridge bottom brackets last a long time, so it's likely you don't necessarily have to change it as long a the spindle is in good shape and there doesn't appear to be any grinding or roughness when you spin the cranks (with the chain off is best as you get a better feel for the status of the bearings without the noise and vibration of the chain).
One aspect to think about, is if you choose to remove your old bottom bracket, that will open up your options as far as cranksets go. Now days, the bearings are external to the bottom bracket shell, are far lighter than cartridge bearing BB's, and the cranksets are two piece: the right arm with it's chainwheels also has a spindle attached which the left arm slips on to and connects the system together.  While they sell and advise the use of special tools for these bottom brackets and an aspect of the crank, one can get by with more common tools used with good sense


What is the best way to test out a niche bike when shops rarely have them in stock?

I have two main approaches:

look for someone who owns one who is nearby. With recumbents and tandems this is often easier as there are clubs and online forums for people who own them. For unusual-but-not-too-unusual bikes you may have to ask questions on local cycling forums and hope for the best. With fora like strava encouraging people to list their toys this can be easier than it might sound. Most people are fine being approached with "that's a great bike you've got, I'm interesting in buying one and would like you to rave at me for a while about why you bought it".
When I want to test ride something very specific, I'll ask the importer or manufacturer for help. Often they can say "we shipped exactly what you want to shop X", so at least you have some chance of finding it by ringing the shop. Or they may have one available that they're willing to ship to a local shop for you to try.
if it's just sizing, I find measuring myself, getting the measurements of the bike I'm interested in, then comparing the bike I want to a bike I have works ok most of the time. Even if the geometry is a bit different I can at least assure myself that the bike I'm ordering is close to the right size. If you want to get really keen, find a shop with a bike fit jig and set that up to exactly match the bike you're buying. It'll take time and you'll probably have to pay for it, but if it's worth it to you, do it.


Is component's thread torque a factor in how 'stiff' a bike rides? Would a racer want higher torque?

There is an extremely small stiffening effect because the interface contact area increases slightly. But in aerospace we usually consider this a negligible effect. To make a system stiffer all the parts have to become stiffer, which of course does not happen because you tighten a bolt in the system


Chain skipping mid cassette after a clean

It's possible that during cleaning a grain of sand, for example, has become stuck in the chain causing a stiff link which does not travel cleanly over the cogs. Cleaning chains and cogs often involves a significant amount of moving dirt around before extracting it.

A simple test for this is to move the chain through both hands bending every link. You'll find a stiff link very easily.

If that's the problem, clean the link until the stiffness goes, re-lube and you should have no further problems.


Possibly you were thinking of Ciasta aero seatposts which has a similar logo?

Something like this perhaps...


Normally, the cap just unscrews. Obviously, that's not the case here. Use something like the tip of a knife, a small screwdriver or a chisel to break it up and pry it out. But try not to mess up the threads too bad, you'll need them for the next step.

I think what you have is a square-taper crank design; the bottom bracket spindle has a square-shaped tip, the crank is wedged onto that tip and secured in place with the nut. Once the nut is off, you'll need a crank puller. It's a cheap tool, you can get one at any bike shop. The puller has a sleeve that threads into the crank (into the same threads that the cap attaches to); then you screw down a bolt inside the sleeve that pushes against the spindle, and hopefully pops the crank off. This looks like an old bike, so it might be stuck on there pretty good.

When reassembling, just put the crank back on and tighten the nut. Make sure you put plenty of grease on the mating surfaces.


Discouraging motorists from stopping at an intersection when they have the right-of-way

This is not strictly a bicycling issue. Do-gooders who ignore the rules and want to give the right of way all the time are also irritating to other drivers. They are not necessarily safer drivers, because "scared" is not exactly the same thing as "safe". There isn't anything you can do; just take cautious advantage of the right of way and keep going. The most aggravating of the lot are those who act as enablers aggressive drivers, like those who cut in to get ahead of dozens of cars in a traffic jam.

It's not really appropriate to enter into anecdotes, but I'm compelled to give one anyway. Once (while driving, not cycling), I stopped at a stop sign in the middle of a residential neighborhood (properly, I might add; a full stop behind the painted line).  Another driver was going cross-wise, not herself facing any stop sign and thus having the right of way. This driver stopped, motioning me to proceed. I shook my head and pointed at the stop sign to indicate that I'm simply following the rules and expect everyone to do the same. She simply refused to budge, so I turned off my engine and engaged the parking brake.  I cannot remember who first yielded (or should we say, "unyielded", if you will), but I do remember that minutes passed. I remained calm and maintained an amused smile while she appeared to become angry.

Some of these do-gooders are, evidently, quite vehement about pushing their viewpoint that the rules of the road are not entirely satisfactory and should entirely be ignored in their entirety (and perhaps not even known at all) in favor of some inefficient ad-hoc social protocol.

In my experience as a driver with several hundred thousand km under my belt, you better just do what they want you to do, otherwise minutes will be wasted like in the above social experiment that I don't care to repeat. However, make eye contact with a driver before jumping in front of their car, and do not waffle; if you're given the right away, take it swiftly.


Difference between a professional bike restoration place respraying and power coat company?

A really good question and one that a pro in the bike painting/PC business would be best suited to answer, but this is what I know about it:

Bikes need special care, or at least an operator that understands the important parameters, in the stripping, blasting/prep, and heating stages. For example, I've heard horror stories about taking a frame in to a general industrial powder coater or painter and they used a torch to assist in getting the original paint loose, but got overzealous (i.e. didn't calibrate their actions for how little mass bike frame tubes have compared to their typical work) and destroyed some brazed joints and braze-ons. Similarly, a lot of blasting media is well capable of damaging brazed joints if not used with care. Bike people have equipment setups and technique that make it a non-issue, but bad things sometime happen when more general purpose companies do it. (Note that I'm not trying to pigeonhole anyone, and there are a lot of very thoughtful people that work at said general purpose companies who can correctly handle any metal object you give them, but I do think the risk is there.)
Finish work on bike frames well is more highly specialized than many imagine, especially when it comes to showcasing and not obscuring fine details, particularly on lugged bikes, and especially on upper end/handmade ones where the builder has done lots of thinning and shoreline work. With powder in particular, companies are mostly in the business of putting big thick economical coatings on relatively smooth, round, heavy things. There's a much smaller subset of powder companies that specialize in thin but durable coatings like what you'd want on bikes. (There's also a whole other discussion about how thinner might be inherently more durable with various finishes, especially powder, at the trade-off of taking more work to do right.)


How would you recommend securing a pannier rack on a bike without braze-ons?

The two options you mention are widely used.

Another option is a seatpost clamp with rack mount points
There are a variety of makers and styles, here is one example.


That is old grease with debris in it, this will be shavings of the bearings and their channel.

Before re-greasing the headset you will need to degrease it to remove all of the old grease, otherwise the old grease will attack the new grease rendering it less effective.
Then once degreased you will then need to clean out all of the degreaser (again so it doesnt attack the new grease) and dry it out.
Then you can add the new grease, the thicker and gloopier the better


Spokes loose on a new wheel, is this expected or a bad build?

Apart from an impact, if it's been twisted in a bike stand wheel slot or something that could cause loose spokes. But usually loose spokes on a near-new wheel is just a bad build - if the spokes haven't been stress relieved properly they'll generally untwist as you ride it. And some wheelbuilders don't use a spoke tensiometer so regularly produce wheels that loosen over time.

Either way, take it back to the shop and ask them to fix it. When you collect it after they fix it, pay very close attention the very first time you put weight on the wheel. The first revolution with load on it is crucial - if you hear pinging noises that is the spokes untwisting themselves as the tension goes off them (the ones at the bottom have less tension due to your weight pushing down, so there's less resistance to them untwisting). That means the wheel hadn't been stress relieved properly (because you just did it), so the spoke tension might not be correct any more (and the wheel might no longer be quite true). If the problem happens again take it to someone different - someone who can't fix a wheel they built is not worth your time.

In more detail: as a wheel is built or trued each spoke nipple is turned. Because there's friction between the nipple and the spoke, this tends to twist the spoke as well as tightening or loosening the thread. Stress relieving means (gently) applying force to the wheel to momentarily loosen each spoke, allowing them to spring back into the non-twisted position. This slightly reduces the spoke tension, and may even unscrew the spoke slightly out of the nipple causing further loss of tension. So after stress relieving a good wheelbuilder will recheck the spoke tension.

EDIT by an anonymous user: Bladed spokes shouldn't twist because as they are built they are held with a tool which does not allow that.

A good wheel is not just true, it has even spoke tension. Over time uneven spoke tension tends to pull the wheel out of true, and the tight spokes are more likely to break in an impact, while the loose ones are more likely to break from metal fatigue. There's much discussion of this online, and Jobst Brandt's "The Bicycle Wheel" is a deceptively concise but detailed explanation of a lot of the issues. It's worth buying a copy if you're interested in wheelbuilding (I don't get anything out of you buying the book, I just think it's an excellent book).


By using a larger sprocket and/or smaller chainring, you can gear an internal hub to cope with just about any gradient. (There is an eventual limit where input torque can destroy the hub.)

(Edit: @Rider_X is right that the Shimano limit is more restrictive than I remembered. There are people using lower gearing and reporting no problems, but you might have to be careful. On the comparison chart below the Rohloff could be geared quite a bit lower (30:16 rather than 44:16, see Rohloff), but the Nexus is following Shimano recommendations according to this forum post))

A cheap hub will give you three gears with big gaps between them and a limited overall range, and although you can make the bottom gear low enough for a steep gradient you might find it too restrictive; a very expensive Rohloff hub will give you 14 gears with gaps and range comparable to a derailleur system (but without overlapping or duplicate gears - a 27-speed derailleur system doesn't have 27 usefully different gears).
In between those, there's a range of hubs available giving you more gears, more overall range, and smaller gaps, as you pay more. See, for example:

http://www.cyclinguk.org/cyclists-library/components/transmission-gears/internal-gear/internal-gear-ratios
https://hubstripping.wordpress.com/internal-gear-hub-review/


Use of winter (studded) tires on only one wheel?

One winter tire is better than none if you're going to be riding in snowy conditions, so go ahead and throw it on. If you do end up running only one tire, you'll probably want it on the front wheel so you don't lose traction while cornering and so that you can maximize braking performance.


Yeah, by the time you have five spokes broken it may be that only one more and it'll collapse (depending on exactly how the broken spokes are arranged).  Plus with that many gone the others are under much more serious stress.

In the general case you may have a spoke go now and then and, if you replace it reasonably promptly, it doesn't imply any serious problem.  But when spokes are going right and left it usually means that the spokes are nearing end of life and they all need to be replaced.

On a good quality bike with stainless spokes, well cared for (and not abused by jumping, etc), the spokes should last at least 10,000 miles and possibly 30,000.  On a lower quality bike, however, with galvanized spokes, corrosion will often do in the spokes before they reach 5,000 miles.  And exposure to weather could cut that number in half.

Depending on the quality of the bike it may be cheaper to buy a new/used wheel than to have the existing wheel "relaced".  But you need to do one or the other -- that wheel could collapse on you tomorrow.


For a full diagnosis, remove the chain, and unbolt any cabling. With just a hand, push the RD body in and out. As long as the RD is free to move and returns back in line with the smallest cog and retains some mild resistance to inward pressure when lined up with the smallest cog, then it's less likely an RD body spring.
Try shifting the derailleur by pushing in on it while you pedal and then letting go. If it shifts well then the spring is not terribly weak. Now try wrapping a rag around your fingers and pulling up on the shift cable at the chain stay and then at the down tube and note any change in shifting to the small cog. If it slows down a lot then you've identified where the friction is, and it is friction that is most common cause of shifting problems down the cassette.  Given the new and lubed cables and housing you're dealing with, how about a closer look at the shifter? Perhaps cleaning and lubing that will fix the issue.


Power to weight, FTP and Terrain Profile

On flat terrain raw power is what is more important than Power to weight ratio.
On rolling terrain P/W is important, but the larger rider still has the advantage.
On mountainous terrain P/W is the determining factor.

You can see this from races in pro cycling.
Flat races are won by large strong riders and sprinters.
Rolling races are won by mid size riders with punchy acceleration, but not the highest FTP or P/W ratio.
Only in the mountains do we see the riders with the best P/W ratios winning.

So yes, in this case rider 2 will be significantly stronger, as he can match the lighter rider on the climbs and has a huge 90W extra on flat sections.

Speaking from personal experience as a 60kg rider, even riders with a lower P/W ratio than me can put me in big trouble on the flats even if I can destroy them on a long climb.


Take everything apart,get all the grease out of the bb and feel inside where the bearings go,it should be fairly smooth,do this to both sides and compare the "feel" of each..If it doesn't feel right(burrs,cracks) there's your problem...I just replaced the bearings in my bike and they were 1/4 inch but your bearings will probally be metric in that general size,it's easy enough to find online...don't skimp on the bearings,get grade 25 bearings,there the best...amazon has them for short money and good luck


How did my rear freewheel become incredibly tight overnight?

I decided to put up another answer because while Daniel's hunch and Billy's excellent answer get at the gist of the solution, I did find some specifics that might help someone else (though perhaps only a SRAM S27 owner).

First of all, the service manual is pretty helpful.

In my case, the "end cap" was tighening on its own during rides.  Normally, this little set screw is supposed to keep the end cap from threading or un-threading (ie. you get the adjustment just right, apply the set screw, and it should all just stay put).

The set screw actually applies pressure to a rubber o-ring, which in turn presses against the threads on the axle to keep the end cap from turning.

On my wheel, that o-ring had actually partially disintegrated where the set screw contacted it.  So instead of pressing a healthy o-ring against the threads, it just sort of mashed some rubber particulate in there.

The right solution to this problem is probably to get a new o-ring.  The route I took, however, was to rotate the o-ring about 90° so the set screw was once again above a healthy bit of rubber.  I then re-adjusted the end cap tension and re-applied the set screw.

Hopefully that keeps me going for a while without tightening up again.  Thanks for all the help, everyone!


The mechanism that allows disassembling the frame is called an S&S Coupling, Bicycle Torque Coupling or BTC.  Searching for bikes with this mechanism should allow you find other models of bikes that can be disassembled in the same manner.


That sort of bike is generally called a hybrid/commuter in the UK (and I think it may be similar in the US).  There are plenty of other manufacturers.  Not all hybrids will meet your requirements but there will be quite a few that do.  You can almost certainly find one with 26" wheels if you prefer too.  I personally find the larger wheels good though, so I would recommend you simply go for a test ride.

The problem with finding them is really a lack of consistency with the terminology
across shops, countries and manufacturers.  There is also simply the problem that with so many different bike types and configurations bike shops will only stock a selection and your required bike may not be in that selection.  There is however a reasonably good chance if you can find one close in the shop that they will be able to order in the right configuration for you.

Update: tried to reflect confusing terminology a bit better.


Different chains, including modern ones, have all sorts of patterns or markings on the tips of the pins. On some there's some level of intentionality to it as a shift aid. There are no bike chains where all the links are screwed together. (There are some half-link styles where the pin screws in place, but that's a tangent.)

The pictured chain is an older bushing-type chain, which was the norm until bushingless chains took their place.

From the look of the cranks/rings/guard the bike is a bike-boom era 10 or 12 speed (as in 2 front chainrings and either 5 or 6 rear cogs). If so, chains specific to such drivetrains, which are labelled 5/6 speed usually, are still made and available. You could order one, but many shops don't carry them, instead choosing to use more modern 8-speed chain for replacements on such bikes, which works perfectly.


What things should I look for when purchasing a fixed gear bike?

You are likely going to get some opinionated comments and answers in response to this question.  There are lots of good brands (frames and complete bikes) from all over the world.  There are more and more options showing up in local bike stores, so if you can it will be best to go have a look.  Even if you choose to purchase online, having spent some time looking at physical hardware will help you make your decision.

I'm going to make an assumption that you're asking about a fixed gear bicycle for road use as opposed to a track.

If you haven't read Sheldon Brown's detailed article then please do, it's a great place to start.  Without reiterating all of the detail in that article I'll simply point out a couple of highlights:

The number one thing that you should look for is a brake.  Again, others may offer dissenting opinions on this, but riding a fixed gear bicycle on the road without a brake is extremely dangerous.
Chain tension mechanism.  You will have to be able to tension the chain on your fixed gear bike as it lacks the derailleur and pulley mechanism that handles that task on traditional geared bikes.  This will likely be accomplished by means of horizontal rear wheel dropouts within which the wheel moves back and forth for adjustment.  You may also encounter models with an eccentric bottom bracket mechanism.  These typically add some weight and may be of less interest to you unless you happen to go for a rear disk brake (in which case moving the rear wheel to adjust chain tension is not an option)
If you are new to the world of fixed gears then you may be interested in having an option to run a freewheel as well.  A flip-flop hub can offer the best of both worlds in that you can ride fixed or flip the wheel around and ride with a freewheel.  This adds a small weight penalty and absolutely requires that you install a brake of course.

As for price, brands, geometries, gear ratios, frame materials etc. this is very much personal preference and the rules are the same as for any bicycle.  You can typically splurge a little on a fixie because there are far fewer other components that you have to purchase and maintain.


Is there an (un)official rule about twisting back a seat on broken bike for CitiBike or other shared bike programs?

This appears to be a widely-used, but unofficial way of communicating that the bike is broken and should not be ridden. See the Wired article that documents this trend: "Courteous Citi Bike Riders Are Alerting Others to Broken Rides" by Christina Boddington.

Also, on Twitter, you can find numerous examples (many of which were cited in the Wired post).


What cantilever brakes are compatible with Surly Pugsley 100mm front fork?

Any medium-profile or low-profile cantilever brakes should work on the Pugsley; so long as you're using the Large Marge rims the effective cantilever post to rim spacing should be basically the same as a normal bike. The default spacing for most cantilever bosses is 80mm for use with a ~25mm wide rim.  On the Pugsley the bosses are spaced 120mm for a 65mm rim.

The Shimano "link wire" style straddle cables will almost certainly be too short,   For clearance, with whatever brake you use I'd plan on making it work with a high-quality yoke and a long straddle cable, as used on a wide-profile cantilever. You might even be most successful dialing in your own using a set of cable knarps.


How easy are Parabolic v. Standard Rollers to use?

I've never ridden parabolic rollers myself but I do have a pair of cylindrical pvc rollers. It takes a bit of practice, but after a short amount of time I was able to watch tv quite easily from my cylindrical rollers. A bit after that, I was able to sit up, lean back down, take a drink, and ride with one hand or one foot while watching tv. Not all at the same time, obviously.

It is my understanding that parabolic rollers are easier to learn to ride simply because you can't ride off the edges. However, riding off the sides isn't a big deal. The bike comes to an immediate stop. The friction of your tires isn't enough to overcome your body's lack of inertia. You smell burnt rubber and may leave burn marks on your carpet, but that's about it. If you put a towel under the rollers, you won't have to worry about the carpet.

One other thing to consider is the diameter of the riding surface of the rollers. I believe that on average parabolic rollers are smaller than cylindrical rollers. Smaller rollers heat up more quickly and as a result are harder on tires.

I've really only addressed the issues between parabolic and cylindrical rollers here because that seems to be the brunt of your question. For a more comprehensive disucssion of rollers, see this question and the questions that are linked to in the accepted answer on that question.


What road hubs models or manufacturers use replaceable cartridge/sealed bearings?

Maybe approach this the other way around. Identify the wheels you like (one or more model) and as part of your purchase decision, see how easy it is to source replacement bearings.

If there are many and varied places to get the bearings from, not limited to cycling retailers, then you know getting replacements will likely be straightforward. You’ll have done the best you can for now.

6903 RS is a bearing size I’ve seen often enough.

I haven’t got to the heart of the question of course, I also would still be interested if other people know whether there is anything like an industry standard right now.

Update: one resource is a poster produced by Elvedes of the aftermarket bearings they produce.
https://elvedes.nl/wp-content/uploads/2018/07/Elvedes-Poster-v4_web.compressed.pdf
Maybe not exhaustive or guaranteed for the future, but could prove helpful.


Options for fully lined bulk cable housing

You can buy 30 meter rolls of cable housing such as http://www.wiggle.co.uk/transfil-gear-casing-30m-box/ . I would opt for Shimano or Transfil, as have seen problems with the much cheaper Clarkes.

Brake  cable housings  have a completely different construction to shifters. The housing is a coiled sheath , compared to the axial strands in shifter housing. And brake housing is larger diameter. So different housing for different purposes.


How is the quality of alloy sprocket 10 speed sprocket?

There are a lot of small boutique-factories machining extra-weight-weenie parts that serve three purposes:

Provide some weight advantage to very high-end racers who reached the limit of their training levels. That could mean positions in a very high-level race;
Satisfy some folks (whose population is increasing) who don't mind throwing money out the window to have the most exotic and customized extra-high-tech bikes;
Feed the Weight Weenie Contest members with lots of ways to shave weight of bikes they don't necessarily ride (but most probably take a lot of pictures hanging from scales to post online).

(ok, that was somewhat a bitter answer, but I think this is not far from the truth)

And, yes, this means 3 months of riding, then to the thrash can, for the cassette you mentioned. How can anyone afford that?!?!?!?


Is the lack of activation in sore calves indicative of a poor stroke technique?

Basing workload or technique on soreness is a poor indicator of what is going on. You could have bad pedaling technique and never feel it or have great technique with no fitness and feel sore right away.

It's likely that you are not using your calf muscles as much when you cycle as when you do stairs. Stair running is a great way to train most of the muscles in the leg, and the extension/flexion coming from the edge of the stair is what causes your calves to be sore later. While I don't have any professional experience to back this up, I believe that cycling doesn't quite put your foot through the same range of motion, thereby activating the calf less(I suppose you could point your foot up and down more, but that's bad form).

What you are likely seeing is a comparison between two activities that use similar muscle groups in different levels. Example: pulling up on a pedal (with cage or cleat) is different than simply lifting your leg up to the next stair since the pedal provides some resistance.

My recommendation: rest it for a bit, maybe a day or two and then do both activities moderately and see if you notice any pain. If you do, consult a physician about it.


Wheel conversion to Fixed gear (threaded hub)

Fixed cog can't be properly installed on your wheel. Hubs intended for use with track cogs have a separate smaller reverse thread for the lockring. The reason for reverse thread is that when you apply reverse torque, it unscrews the cog but tightens the lock ring so that the cog stays in place.
If you absolutely have to use track cog with this hub, there are bottom bracket lockrings that fit the same thread. With thread locking compound and lots of torque it sort of stays in place. This setup is called suicide hub, and it really should not be used except with rear brake and very careful braking.


Trick or tool to help line up 48 splined crank arms

If your bearings are decent, just take the non-drive pedal off and let the pedal weight pull the other side down, or slowly let it fall from slightly off center. This is how I could tell with my Bullseye cranks, besides hopping on and trying to pedal it. If that doesn't work then I'd try tying a heavy weight or looping a paint can around one of the pedals close to the crank.

You're looking for a 7.5 degree distance, so on 185mm cranks that's 24mm or nearly and inch of diference between splines. Weighting the opposite side enough should make it clear. I then took some nail polish and marked both the crank and axle so I didn't have to play this game again.


The closest to that is the Sachs DD3 "dual drive" hubs that are a 3 speed IGH with a standard cassette mount, available in 8,9 or 10 speed cassette versions. According to this site the ratios in the hub are 0.73,1,1.36 giving 1.86 between high and low gears. That's wider than a double chainring setup but narrower than most triples (a 20/30/40T triple has a ratio of 2.0 for example).

Those apparently weigh less than a triple crank and derailleur, but since you want that as well as a double or triple you will be adding the weight, as well as the cost and complexity rather than substituting it. Sheldon Brown has done this with the older 3x7 version and seemed to enjoy it.

The issue is the size or complexity of the shifts. Rather than just having two overlapping gears from two chainrings, you now have 6 or 9 overlapping gears in much of the range (so there's lots of ways to get a given gear ratio). When shifting from high to low in the hub you either experience a big jump in final ratio or have to shift significantly on your other levers at the same time. If you went from, say, hub low on the 15T cog on the cassette to hug high, you'd probably want to shift to about 25T cog so the jump was a normal step between gears. Typically that will be three or four cogs.

The Schlumpf Mountain Drive gives a 2.5x gear down in the bottom bracket but I'm not sure they're still manufactured. I've used one of those and found it effective but the jump in gears was huge. It was more like shifting between low ratio and normal in a 4WD vehicle than a normal bicycle gear change. Typically I'd go from bottom gear on the derailleur system to the smallest cog on the cassette when I changed, but often the bike would almost come to a halt when i did that because I was going up a hill and not pedalling hard for the 2-5 second gear change cost me all my momentum. I fear that a similar shift in the rear hub would have the same effect.


Where is the valve in my handpump - and what stopped it working?

If I understand correctly you're feeling the same pressure on the compression stroke as the extension stroke?

The mini dual g pumps air during both compression and extension strokes so this would be normal behaviour https://www.topeak.com/global/en/products/pumps/239-mini


Why do you think I nearly fell on this turn?

You braked too hard given the road conditions, plain and simple.

The road was wet, which decreases your traction. You hit the brake, which uses the tire's traction on the road to slow the bike. If pressed too hard, the rear wheel will lock up and skid, which can be disastrous in a corner — the rear wheel will continue to follow its outward momentum. 15mph may not seem fast, but that particular corner may have been especially dangerous for any number of reasons:

wet leaves are notorious for being slippery
automotive oil collects on the road if it hasn't rained in awhile, or if there's poor drainage
there was a dip in the road
the road may have been off-camber (the road slopes down toward the outside of the turn)

To avoid accidents in the future, the first thing you should do is properly learn to use your front brake. The front wheel will not skid under reasonable cycling conditions. Other than that, you'll over time develop a sixth sense of how safe the road conditions are. Just pay attention to the corners and watch out for dips, debris, puddles, and the camber of the turn.


bike suggestions for a commuter who takes an occasional long road ride

It sounds to me like you want a fairly simple bike with rear hub gears, styled similarly to a track bike...  There's now "Urban"† bikes that match up to that category... The traditional thing would be to take an old 10-speed (horizontal-dropout) or singlespeed and replace the rear wheel with a 3-speed hub. (7 or 8 are common now, too)

Here's a few I found (starting with brands my 3 favorite LBSs carry, then some stuff I've randomly run into elsewhere):

Trek/Fisher Waubesa
Trek Soho or Trek Soho DLX
Less of the fixie styling, but the Trek Belleville is nice-looking and well-equipped for hauling stuff.  (this is one I've considered getting)
Globe Live 2‡
Globe Live 3
Globe Daily 3
Globe Vienna 4
Giant Seek 0
Cannondale Bad Boy ONbike (concept) (but custom would be cheaper)
Cannondale Hooligan 3
Novarra Fusion
Raleigh Cadent I8
Torker KB2 (only 2 speeds, not 3)
Civia Hyland
Civia Bryant
Charge Tap
Charge Mixer

† "Urban" or maybe "City" or "Street" or something that means "road" without actually saying road.  Sort of a silly term that their marketing departments came up with.

‡ If you hadn't heard, Globe is a spinoff from Specialized.


Rear road bike Shimano cassette wobbling during freewheel

I've not seen a cassette that doesn't do this, IMO they all do it to some degree as the cassettes floats on its bearings unless the pawls are engaged. Some say it's by design perhaps to aid with gear changes etc.
I used to have £2000 road bike with custom built wheels that used to do the same thing,  it never caused any trouble even after many thousands of miles riding.
Unless it's causing specific issues I wouldn't worry about it.


Smartphone mounted on handlebar: Will vibrations during cycling damage it?

The vibrations will be hard on it.  The result will not be instantaneous failure,  but an increasing likelihood of failure after perhaps several hundred hours of riding.

The likelihood of damage can be greatly reduced with a resilient, shock-absorbing mount of some sort (I assume most commercial mounts include some shock-absorbing function).

Most important is to avoid mounting in a way that the device will bang against the handlebar, or rattle in its mount.  A mount that is too flexible can actually increase the G force the phone is subjected to.


Vibration from pedals at slightly higher speeds?

You may be feeling vibration coming from worn bearings in either the pedals or bottom bracket. Something this is only discernable when applying greater force to the pedal and crank - which would explain why you feel it in the down stroke but not return stroke.
Manually turn the pedals feeling for excessive resistance, 'notchiness', clicks or play. Do the same for the cranks. If you can slip the chain out of the front derailleur cage and off the chainrings it makes it much easier to feel any problems when turning the crank, because there is no drag or vibration from the chain.


My chain is catching on a part for which I don't even know the name

The part is a front derailleur. It job is to shift the chain between the front gears. Change gears while looking at it, you'll notice it moves and pushes the chain between sprockets
You need to adjust it, removing it would actually require more effort since it will need you to delink the chain somewhere. Also, removing would remove your gear shifting functionality.
What you're describing is a common thing that happens to drive trains over time. The cable attaching your gear shifter on your handle to the derailleur near the pedals, has either stretched if it was low quality, or slipped a little at the derailleur. The fix is quite simple. All you need to do is locate the point at which your cable attaches itself to the derailleur(you can do it by following the black tube coming out of your shifter on the handlebar, along the frame of your cycle and ending somewhere opposite the derailleur on the other side of the cycle) It looks somewhat like this- .
Shift your bike down to the first gear. Then locate the screw that holds the metallic cable coming out of the aforementioned black tube and loosen it enough that the cable can slide around just a little(In the image above its the screw which the right end of the double arrow is pointing at).
This is the tricky part, you might want to ask a friend to help if you don't have fancy tools. Move the derailleur like as if it were shifting the chain to the second gear.This might bend your chain a little, that's OK. Notice the stretch of cable visible and marked in the picture would have become noticeably slack. While still holding the derailleur in its forced position, pull your cable taught by pulling the end beyond the screw. Hold the point where the cable is attached with your fingers while letting go of the derailleur. Make sure you don't let that point move, it will take some effort, they make the springs rather tight. Now slowly let the cable loose again by moving the attachment point in the direction the spring is pulling it till the derailleur is exactly centered on the chain, a little closer to second gear position wouldn't hurt though. Holding the attachment point in position, tighten that screw holding the cable.
As a safety measure so that the next time your cable loosens, the chain doesn't fall off, you could adjust the minimum position screw as described below-
Flip the bike right side up. On the top of the derailleur attachment, you'll find two small identical screws right next to each other. Something like this-

These screws prevent your derailleur from moving beyond its maximum and minimum positions, it seems in this case one of them came loose and shifted letting the derailleur push the chain off the sprocket.
With the cycle in third gear, locate which one of the screws is closer to the obstruction below it (You can tell what this obstruction is by forcefully trying to shift past the third gear like as if there were a 4th gear. You'll notice the obstruction in question is pressed against the end of one of the screws when you do this). Once you've done so, pick the OTHER screw and tighten it till the point that it just touches the same obstruction when the cycle is in first gear.

You're all set to go now

EDIT:
Since I'm a noob to this forum and don't have commenting privileges yet, I'll put my comment to your update post here.
I only saw the original post which is why i was confused about what was wrong and I mistakenly assumed it to be the extremely common problem of the cable slipping a little due to use.
What you did in the update to your post was actually the correct solution, just not enough. Loosen the screw holding the derailleur to the frame and turn it a little more till the derailleur is inline with the chain(not just clearing it). If the inner edge of it is touching now, follow my instructions above for changing the lower limit, but change the upper limit instead (ie the screw which is closer to the obstruction in the top gear) till the derailleur is centered on the chain in third gear.


Rear wheel keeps moving forward in frame no matter how hard I tighten the bolts. Any solutions?

Take a look at something like this:

http://surlybikes.com/parts/small_parts/monkey_nuts

Edit: this may me more along the lines of what you're looking for

http://surlybikes.com/parts/small_parts/tuggnut

I'm sure other brands make similar things.


What is the best gear ratio for speed on 20inch frame

One may assume that you're a rider somewhere between 5'9 and 6'1.
The best gear ratio for *SPEED will depend on your ability for a) high cadence and b) power in harder gears.

Since I'm predominantly a roadie, I'll provide an answer based on road cycling / TT alone. Let me know if this is the incorrect context.

Since we are talking about speed, I'll start with the harder gears (big ring in front and the small gear in the back).

A lot of bikes ship with compact chainsets (a fairly recent trend have brought back doubles, 52s) which are a 50-34.  That means that the big ring will have 50 teeth on it.  For every pedal stroke, you will feed 50 gear linkages through your rear cassette.  Thus for SPEED, for the fastest riding, you'll want your chain on the smallest gear in the back, which would typically be an 11 (or a 12, but let's assume an 11).  So, if you're on the 50, for every pedal stroke you will force 50 chainlinks through an 11 tooth gear, which will turn the wheel 50 div 11 times. If it's a typical 700c wheel with 23 road tyres, that's usually around say 2.098 metres per turn, or 9.539 metres per pedal stroke.

Get that to 100 cadence (100 pedal strokes per minute, and you'll be cruising at over 57kph) ... ; But, unless you're a pro, you'll probably not be able to do that on the flat.

Cadence. Cadence simply is the name for the number of pedal strokes you can do per minute.  If you are better able to pedal at a high rate than at grinding a difficult gear, then you might get your bike above the same speed mentioned above, by spinning a 50 chainring through a 16 gear at about 147 cadence.  I know of track riders who ride fixed gear 48 on 16 and in sprints can get to 180 cadence, which is over 75kph.

*SPEED: Assumes the fastest speed you can ride the bike.

So, unless you really really know your abilities very well, and want to fine-tune your bike to be specifically fast for your abilities, I would recommend you look no further than perhaps the simple basic compact (50-34) on a 12-28 cassette.

You'll be faster up hills once you build your strength, and you'll hardly ever spin out your hardest gear once you've built your cadence.


What maintenance to do after buying a brand new road bike?

Before each ride I do a quick safety check:

Brakes adjusted correctly
Handlebars correct, wheel in line, headset tight
Saddle/seatpost tight
Pedals and crank look good
Chain looks good
Wheels true (maybe not perfect, but quick spin shouldn't show huge
wobble or brake rub)
Quick Release Tight/Hub Nuts Tight [thanks Kibbee]
Tires inflated

With the exception of the "tires inflated" this takes me about 30 seconds. The "Wheels true" I do by just spinning the wheel and looking at distance to brake pad. After first revolution I can stop wheel where I need to align stem for easy pump.

"Tires inflated" I do by hooking up the pump and topping them off. If I had a flat on the last ride, I let out the CO2 and replace with air, otherwise I just take them back up to whatever pressure I use for the particular bike and conditions.

This list is also the list of things to NOT wait to find out before fixing.

On a new bike, you will also want to adjust for cable stretch on the derailleurs during the initial period. Many bikes have barrel adjusters that make this simple, but looking at the close up pics of the GMC Denali, it looks like this bike does not. Simply put, the lower priced bikes are able to be lower priced in large part by making assembly cheaper and using parts that are cheaper to make. This is NOT to say that it's not a very serviceable bike. Most of the tradeoffs just make it a little bit harder to maintain. The two that affect adjusting cable tension are the lack of barrel adjuster and the use of a regular nut rather than a hex bolt to hold the cable.

You can make the same adjustment, you just have to use a different tool. First, don't worry about this until your shifting starts to get a little bit sketchy. Once/If it does, you will want to shift to the smallest cog ( rear gear) for the rear derailleur. Then loosen the nut holding the rear derailleur cable and just pull it "strong finger tight" and retighten the nut. If this doesn't help there are easy ways to work through it, but come back and post another question so we can make sure we talk you through it.

The front derailleur generally isn't quite as affected by stretch, but if it becomes harder to get into the bigger chain ring (front gear), do the same thing...shift to smallest chainring and loosen nut, tighten cable, tighten nut.

Happy Riding!


Is there any way i can add progressiveness to my suspension, even though it is not compatible with standard tokens?

As @alex commented you need something that takes up some air volume.
Around 10 years ago in the downhill racing scene this was also needed by some heavy riders. The solution was to pour some fork oil into the air chamber to make it take space there. The oil will also eventually get into the negative air chamber when the fork is compressed to the groove on the inside, so the characteristics of the fork will change during a single descent.

The only other solution that comes to my mind (actually it is a bodge) is to use Formula's Neopos volume spacers, and just squeeze them into the fork (its air chamber). Those are foam-based and it might work.

But I think you are better off buying a fork capable of taking proper volume spacers.


Creaking when only in the saddle - I would check the saddle? A drop of oil into the where the saddle rails fix to the seat can alleviate.
But if you are sure it is not this - then perhaps try isolating the noise by using the bike on a static trainer and pedalling. If you remove the chain from engaging with the chainset - it would isolate the noise to the chainset / BB only.


How can I prevent my next bike from being stolen?

That sucks. I'm sorry that your bike was stolen.

If thieves are willing to break into a locked garage, break into a locked and fully enclosed mesh bike parking area then cut two bike locks using power tools: there's not much you can do about it.

If there are lots of bikes in the bike parking area you can make your bike a lower priority target by increasing the number and strength of the locks, and by making the bike itself look less desirable.

Looking at the first picture, it seems the bike parking area door could be easily opened from the inside. The thieves were able to cut a hole in the door and reach the door release - not the most secure setup. Also, it's likely that someone let them into the garage - i.e. one of your neighbors.

Just store your bike in your apartment if you can.


Zip ties don't last forever, so you'll need to keep an eye on them and replace them periodically. P-clips would probably work.


Most hubs these days claim to be "sealed".  This basically means that if you look the hub from the axle end you can't see the balls of the ball bearings, because there is, at least, a "dust shield" that leaves only a very narrow opening between rotating hub and fixed axle.

There are also "cartridge" hubs, which were the original sealed hubs popularized by Phil Woods, back when standard bearings had no dust shields and were pretty crappy.  These use a (theoretically) replaceable cartridge on each side of the hub, where the cartridge is an industrial bearing cartridge similar to what's used in electric motors (and similar to what's used in bottom-bracket cartridges).  However, replacing the cartridges requires special tools, and likely many bike shops would just give you a dumb look if you talked to them about replacing the cartridges.

Both of these schemes are a significant improvement over the original open bearing style, since, not only do they keep most moisture out, they also keep out dust and dirt.  For the average rider, though, the cartridge scheme is probably not worthwhile, since it is not possible to simply rebuild the bearings.


I'd try a screw remover like these. You'll need to either get a set or bring the bolt in to make sure you get the right size (Sears sells their own version that's supposed to be excellent). The good ones have a left-hand thread and a small cutting head to bite into the bead of the bolt; this looks like a really good candidate for a screw remover since the head is nice and large and has enough material for the remover to be able to grab.


If the bike is upside down and the brake levers are pushed then you can force air into the system resulting in the issue you are seeing.

There are a number of things you can try to restore function but if they don't work then a bleed will be necessary.

With the bike the right way up repeatedly pull the brake lever, this can encourage the air back out into the reservoir where it belongs.

If this doesn't work then zip tie the brake levers to the bars to pressurise the system, leave overnight and then try the first step again.

After that it's time for a proper bleed to get the air out of the system.  How you do this and what you need depends on the model of brake and may involve special sryinges and adapters at one extreme and a bit of tubing and a jam jar at the other.

If the brakes haven't been bleed for some time,  years not months, then a bleed might be a good idea anyway.


Do hydraulic road brake levers exist that do not include shifters or dropper post buttons?

Currently, TRP Hylex are one of the only drop bar brake lever (without gears) that has a hyraulic master cylinder. Magura HS66 is another, but these are pretty rare.

Other options include:

Cable actuated hydraulic calipers. These are connected by cables just like normal caliper but the hydralic master cyclinder is at the caliper end, so any drop lever will work. TRP Hy/Rd are the most popular version of these, but other cheaper brads also exist.

Yokozuna Motoko Cable-Pull Hydraulic Disc Brake

Cable actuated master cylinders. These as master cycliders which are attached to the stem or handlebars and are also actuated by cables, so any drop lever will work. Examples of this are Giant's Conduct and Hope Tech V Twin System

Giant Conduct

Hope V-Twin


Fix a broken floor pump, replace pump head

Slica makes a very nice presta pump head (below), the cost in the US is around $35. For that it ought to work well – and it does. The connection is a Schrader (car tire) thread and it is a pain to find a hose barb with that thread. What I did was to cut off the end of the hose and then use the threads on the pump head as a hose barb. I put a hose clamp on it and it holds just fine.


Which usually wears faster - wheel rims or brake blocks?

Rims last a lot longer than brake pads. It's difficult to put a number, as it depends on so many parameters, but personally I change brake pads roughly once a year (2-3'000km), and I haven't ever changed a rim due to it wearing out. (There has always been other reasons to change them.)

On many rims there's a tiny groove in the middle of the braking surface. You're supposed to change the rim when the bulk of the rim has worn down to that level. (But as I said, it hasn't happened to me yet.)

Regarding your other advice, 'replacing cassette, chain ring and chain together', it's not the most common of advice, to put it bluntly. The advice you're likely to get is to  change the chain when it's starting to wear (you have to measure the length of it, either with a special chain-tool, or with a tape measure. If it's increased by 1% it's time to change.) If you don't change the chain it will start to wear down the cassette, and eventually the chain ring - but that takes a lot longer.)


What are these washers that came with my front wheel quick release?

Those washers help prevent your axles from dropping out of the dropouts if your quick releases become loose. In the USA, the CPSC requires some sort of secondary axle retention device -- if you don't have "lawyer's lips," you're likely to have these.

With some solid axles, they also help a bit with the axle nuts not loosening by themselves.

With ebikes, they can serve as antirotation washers, preventing the torque of the hub motor from twisting the axle loose.

They should be flush against the outside sides of your forks, right next to the bolts. There should be a notch in the fork or dropout in which the indent fits. The photo is of solid axle rear dropouts so just imagine them in a vertical orientation with front quickreleases.


Why doesn't my suspension fork rebound after being compressed?

Sounds like you have debries blocking the valve at the rebound chamber. Even if you have no air pressure in the chamber(that means 1 atm) it should still have enough force rise back again after being compressed.

I for once bought a "White Brothers DH-2" which was mainteined recently, or that's what they told me. One day it got compressed all the way(15cm+3cm kit) and got stuck. I opened the tubes very carefully, you know because springs. The "mechanich" sleeved the springs in a piece of rubber(in fact was a cuted out wheel tube) and with friction pieces started to come apart and made it's way to the rebound chamber, forming a plug.

Cleaned it up good, lubed up the seals and changed the oil. Stuff felt like new afterwards.


Do freewheel/cassette/chains come as a set?

Your easiest solution is to simply buy another of exactly what you have

8 speed cassette, 11-28 teeth
8 speed chain.

They don't come as a set - you need to buy one of each.  Its up to you if you want to get cheaper or more expensive parts.  The lifespan and weight is what varies with price.

Depending on wear, your front chainrings might be getting tired.  But I've seen some severely worn ones still working fine.

Any 8 speed chain will be fine - you could even mix and match KMC chain with a Shimano cassette.   But you need 8 speed chain (possibly labelled as 6/7/8 speed) and you need an 8 speed cassette.

If you want to get a bit more adventurous you could look at a 30 or 32 tooth big cog.  This would give you a lower-low gear for hillclimbing.  Its totally up to you whether this is required.

Downside of enlarging the cassette is that your rear derailleur might not fit, or it might chatter on the lowest gear.

Chains come in lengths longer than what you need.  114 or 116 links (or half-links)   So you shorten them to the same number of links as your old chain.

You'll need tools to do this - there are some special bike tools.

Cassette lockring remover (Undoes the lockring retaining the cassette on the freehub)
Chain whip (to hold the cassette and therefore the freehub still while using the lockring remover)
Chain tool (to shorten and fit the new chain you need a chain tool.  Chain will probably come with a one-time use pin, or you can fit a master link to make life easier next time.)

Also need rags and cleaners etc, and possibly chain lubricant.


Do these parts fit my Giant Escape 2 2018?

Yes, I think that would work

The Escape is Altus 8 speed with rim brakes. For a 10 speed replacement group you will not need to mess with the hub, a 10 speed cassette will fit

The bottom bracket shell is threaded as the Escape has a cartridge BB. You'll obviously need to replace that with a external bearing unit. It does not matter if the shell is 68 or 73mm width.

The rear spacing is going to be 135mm. A Deore crank compatible with a 68 or 73mm threaded bottom bracket shell will have an acceptable chainline.


Major Problem: 135mm rear spacing road touring frame with shimano 5800 11 speed cassette?

This is an under-publicized and very frustrating problem. It works this way because mountain 11-speed cassettes have their largest cog attached to the rest of the cassette in such a way that it's suspended over the hub flange/spokes and not taking up any room on the freehub body.

I have no idea whether any of the Shimano freehub bodies for any of their standard axle 11-speed road hubs hubs might be retrofittable to FH-M475. It's not impossible, because many of their hubs and freehubs are cross-compatible in a pinch. If it does work, the resulting hub will be some larger spacing than 135mm and will also have funny axle protrusion because of it. Also new Shimano freehubs for their nicer hubs can be kind of expensive. So it might be possible but it sounds like kind of a goose chase to me.

One Shimano hub that does what you want here is FH-CX75. Centerlock only. Last time I went looking for what you need, this was the cheapest reasonable quality option, but that may have changed. All sorts of cross bikes are coming at the moment with Novatec/Formula/etc hubs of this spec. Hope and White also have good upscale options.


What's the best way to fix up my used bike?

Simple adjustment

It may be that your brakes and gears are simply out of adjustment. The easiest way to confirm this would be to take it to your local bike store (LBS) and ask them for advice. Most stores are pretty friendly and helpful towards keen amateurs.

If they advise that it's just adjustments they can do it themselves, or show you the adjustment screws so you can try it yourself.

More significant work

It may turn out that there is more work required, such as replacing brakes or gears. Also the chain, cassette and chainrings may need replacing.

In this case I'd be very wary of investing too much money into the bike. Buying components individually is a lot more expensive than buying a complete bike. Plus making sure parts will fit can be confusing and unreliable. If there's much wrong with the bike I'd say it'd be cheaper to buy a new bike where you know that all the parts are at least compatible and in good condition.


Is it possible to accurately measure airspeed on a bike, and is it useful?

There are devices designed for bicycles that measure airspeed. And older example is the iBike, but there are others. The iBike is intended to be used as a stand-alone power meter, and makes assumptions about the drag area and rolling resistance of the bike/rider, then combines those assumptions with speed and gradient information to estimate power.

The other airspeed devices (for example, the Notio Konect) are used in conjunction with an on-bike power meter to determine aerodynamic drag; the on-bike power meter measures power, an on-bike speed sensor measures speed and acceleration, and (sometimes) other sensors will measure gradient and air density. From these measurements, aerodynamic and rolling resistance drag can be estimated. Of the airspeed measurement devices that are currently available as of January 2020, none measure yaw -- they only measure airspeed from directly ahead. There are a few devices that are in development that do measure yaw.

This SE.bikes question and answer describes some of the calculations involved in the estimation. A brief description of how the iBike estimates power is discussed in this SE.bikes topic here.


The spring in my front dérailleur is jammed

I went to my favorite cycle mechanic and he dropped kerosene on the derailleur and then brushed the dirt off easily.


You said in a comment that you switched from a 100mm stem to 120mm, this made it worse so you went back.  I suggest you try an 80mm stem, maybe it will be even better.

As for raising the bars, you do have some options:

Get a high-rise stem.  There are plenty available, look for 25 degrees or even more.  Like this: http://salsacycles.com/culture/new_promoto_25_degree_stems
Try a riser road bar, like this: http://www.fullspeedahead.com/products/handlebars-road/k-wing-compact-handlebar/
Lower your seat.  This raises the bars' relative position, which may help.  Don't lower the seat too much though.
Buy a new fork.  Either get a longer steer tube which you can put more spacers on, or get a carbon-legs, aluminum-crown model which you can use a steerer extension tube in.


The usual trail etiquette rules are, basically:

Cyclists yield to everybody
Everybody yields to horses
If you're both cyclists (or both hikers, etc), somebody going downhill yields to somebody going uphill

So as a pedestrian going uphill on a narrow path, the cyclists were supposed to yield to you.  However, if you looked like you were stepping off the trail, they probably assumed you wanted to let them pass.

Yield means something like: slow down to the hiker's speed, and if needed pull to the side and let the hiker pass, and depending on conditions would likely mean needing to stop entirely.

See also:

http://www.imba.com/about/rules-trail
http://www.imba.org.uk/WhereToRide/TrailEssentials.html (the UK says "Give Way" instead of "Yield")
http://www.romp.org/modules.php?op=modload&name=Sections&file=index&req=viewarticle&artid=8#hikers

Cyclists that don't yield on trails scare other trail users and eventually lead to controversy over cyclists on the trails and possibly closing or limiting access for cyclists to those trails. For instance, Mount Tamalpais was important to the original development of mountain biking, but cyclists are now banned from many of its trails.


Would a seat post mounted back rack act like a rear fender?

I'd say it depends on the length of the rack you're going to attach.

It's all about the physics - the water droplets, when they detach from the tyre they move perpendicular to the perimeter of the wheel. If the rack is long enough, the droplets that might reach your back are hitting the rack (acting as a mudguard).

The ideal situation would be when the rack reaches to the furthest rear point of the wheel. Then only the droplets travelling vertically are not covered by the rack.

However when the rack gets shorter, the more droplets travel to the front, thus direction of your back.

Short story long - have a look at the picture:

black is the bicycle (obvious)
red is the rack
blue is the  most front-travelling droplet that might hit your back

I hope you get the idea.


Separate hex keys vs. combined multi-tool for bike adjustments?

For use at home, there's no question that separate keys are more useful and more economical.

A multi-tool has limitations that make it cumbersome to use in tight spots because all the keys are attached to the tool.  Separate keys suffer no such limitation.

Separate keys can be bought and replaced individually and very inexpensively -- not so with a multi-tool.

I wouldn't buy the ridiculously expensive set of keys you show in your post.  Just buy the keys you actually need. Drop by any local hardware or automotive parts store and buy the hex keys you actually need.  They are inexpensive and should last a lifetime as long as you don't buy the cheapest thing they have.  Like all tools, it pays to buy quality.  Although you can buy them online, I prefer to buy tools where mechanics buy them.  Automotive supply shops such as NAPA in the US are usually your best bet.  They cater to mechanics so they won't sell cheap crap.

Torque: There's no way you'll ever produce correct torque with a multi-tool unless you're an experienced mechanic who "knows by feel" from thousands of repair jobs.  Individual wrenches are also longer and give you more torque than a multi-tool.  If you need even more torque in order to remove things like pedals, you just use a bit of pipe to add leverage.  I keep a narrow piece of steel pipe about 12 inches long in my toolbox just for this.  You just slip it over the long end of the Allen key and it gives you all the torque you'll ever need.  Some people prefer the wrenches with plastic handles attached such as those made by Park Tools, but that's purely a matter of personal preference.  I prefer plain wrenches with no handles on them since the handle means it can only be used in one orientation, not two like a wrench without a handle.

Losing them: My set of Allen wrenches dates to the 70s. I don't understand how you lose tools from your own garage.

But on the road? Yeah, sure, I carry a multi-tool like everyone else; but your question was about home use.


You  probably will waste more time trying to identify the bike compared to just replacing the BB.

Two options - Easy but likely more expensive - take the to a bike shop have them supply a BB of the correct size, if they supply the wrong size, they should be prepared to swap it.

Or buy one cheap off the internet (probably 68x115) and if its the wrong size, well you have a spare the wrong size for you current bike.

Its unlikely a spindle length of a couple of millimeters too short or long (i.e. one size up or down) will make a major difference. The worst happens is the front derailleur rubs when cross chaining. BB are cheap - $10 for a cheapy, $20 will get a reasonable quality one for that bike. So it won't break the bank if you buy the wrong size first time.


Sounds like you have a BB30a bottom bracket (30mm spindle and 46x73mm shell). In order to run any Shimano Hollowtech II cranks you will need some form of adapter to reduce to a 24mm spindle. There are a few available (obviously your existing one) as well as some such as WheelsMfg.

The Shimano bb-mt800-pa is too small a diameter for your BB (41mm vs 46mm), you need an adaptor. The 89.5-93 is the full length to the outer shell. On a 68mm bb you need spacers between the bb and crank.

Both the M522 and M667 are Hollowtech II so the new cranks will work with the old BB.

Other considerations for shifting from 3x10 to 2x10 are chain line, front derailleur and shifter.


What type of bicycle bell is easy to use with winter gloves?

I personally have found that anything with a lever that moves the internal clapper works best. Unfortunately, those seem to only come in large size.

Here's a photo of the one I have lying around:

I thought the spring in the internal mechanism had worn out which is why I wasn't using it, but now that I looked at it again it turns out it just needed a bit of oil.

Here's what the insides look like:

The clapper's attached to the lever with a spring so any contact with the lever won't dampen the clapper's movement.


What is the proper technique for crossing railroad tracks?

Approach at something close to a right angle.  Easiest if the track is square to the road, of course.  Only a little less easy if the track on the right-hand side (on US roads) is nearer than the left, so you can, in advance of your approach, swing out into the lane to achieve a square approach.  Much trickier the other way -- you must wait for traffic behind to be clear so you can swing out into traffic as you cross.

Approach at "moderate" speed (maybe 10 mph).  For a single track coast, for multiple tracks you likely must crank, but not too hard.

Quite important:  Raise your butt off the seat and "suspend" your body on arms and legs.  This isn't to save your butt (except maybe figuratively) but to assure that the bike doesn't bounce as it goes over the rails, and the wheels maintain firm contact.

As you approach, always study the rails and whatever is placed beside and between the rails.  Often there will be a gap between ends of wood pieces, eg, and you don't want to get your wheel too near that gap.  Very occasionally there will be a splice in the rails themselves, and that likewise needs to be avoided.

And, as one tour leader once told us, if the rails are wet, crawl across, dragging your bike behind you.


That video is of a relatively supple tire going on easy. It's pretty blasé about the difficulties that can be encountered. He does end at the valve, which is good because advice to do the contrary is one of the most parroted falsehoods in cycling, but he doesn't talk about why.

There is a universal truth of difficult clincher tire mounting situations, and it's simple. You get the last part of the bead to go over easiest when on the whole rest of the wheel, but especially 180° away, the two beads are pinched together down into the well of the rim and kissing each other. And you must finish at the valve, because the valve is the spot on the wheel where the beads can sink into the rim well the least.

You can use force, tools, water, soap, pastes, and thinner rim strips to help accomplish this. Sometimes even strong, skilled mechanics need or choose to employ some or all of those. It is true that oftentimes brains and dexterity are enough, but not always, and not always on an average time expenditure basis either. But the point is that if you want your maximum chance of doing it with hands alone, you have to focus your efforts on the above principle. It's how clincher tires work and there is no trick that's anything but a rephrasing or play on it.

A side note: Sometimes you hear cyclists and mechanics advising against finishing the job with tire levers or using them for installation at all. The basis for this is that doing it carelessly is a good way to ruin tubes and sometimes tires. Tubes when the tube is being reefed on directly by the lever without the user noticing or caring, and tires when excess force is applied when the beads haven't been properly sunk into the rim well, as above, and instead are stuck and won't simply be coaxed in with force. These situations are avoidable, although some tires don't make it easy. I install a lot of 25, 28, and 32mm Marathon Pluses and I usually finish with a tire lever because on balance I find things go smoother that way, but it requires being very careful that I'm not committing the above mistakes.


Riding with a Gates belt past its due replacement mileage: can it snap or other risks?

The mode of failure I have seen in similar belts used in industrial applications are typically one of two types. In the first scenario the belts show physical damage. The teeth may start to separate or be missing. You may also see cracks on either side of the belt. In the second scenario the belt just snaps. A visual exam will show no wear, cracks or damage. What you will see is the ends of the internal cordage be it Kevlar, Aramid or similar fibers. The second scenario is common enough that belt manufactures generally suggest time or mileage intervals rather than visual inspections. Depending on your model (some are easier to change than others) you could carry a spare belt. As others have commented the belt breaking has some consequences other than inconvenience. Any unexpected component failure can result in loss of control and potential injury.


Should I use an already master-linked chain or add a masterlink to a plain chain?

I've been in a number of situations where I was really glad to have a master link that I could pull apart.  I'm a big fan of Sram's chains, and they're pretty reasonably priced here in the US.  In your position, I'd try hard to find a chain with a master link.

With that in mind, it's worth having (and even carrying with you) a spare master link.  If you do blow apart your chain, being able to put it back together is well worth the extra few milligrams in your bike pack.  Since they seem to come in 4-packs, it'd probably be fine to just find a chain and buy a pack of master links.


Why the vertical difference between the right-most point of TT and the left-most (union with ST) is not part of a geometry chart?

That dimension by itself hints at a bunch of different things without telling the full story on any of them. It has implications for how much dropper travel can be run for a given seat height, but you can't figure it out exactly without knowing where the seat tube actually ends. It has implications for how much bar height you can or are forced to have, but again doesn't tell you exactly without a measure of how far the head tube extends above the TT intersection. The top of the head tube can get pushed up to accommodate a given fork travel, but you still need to know what fork axle-to-crown dimension is actually intended.


How do I test ride a bike that I'm looking at buying?

30 seconds in the parking lot: Do you feel comfortable on the bike. Does it fit you (and not completely just "bike fit"...do you like it...dig it...get it). That's what I would spend the first thirty seconds on.

Medium ride: How does it respond and do you like that response. I personally like my road bikes to be a bit "quick and twitchy" but I know a lot of folks that feel like the bike is going to do something on it's own...they want a bike that is a bit more relaxed. Several factors go into this, geometry, materials, components, etc, so best way to see if it matches what you want is to ride it.

Longer Ride: Start with mellow flat if you can to just get a feel for the bike and to warm up a bit. Then pick things up, but this is a test ride, not a race, go 70-80% but keep a bit in reserve...you don't know this bike completely yet. How does it react when you really put some power to the cranks? Do you like how it handles in a bit of a descent? How does it feel in a climb?

I would also check the brakes, drivetrain, etc...but this would actually be lower on my list. The "check the gears and the brakes", for me, is more about safety...if it doesn't shift well and has at least minimally okay components, I (or my LBS) can get it shifting nicely. Same idea with the brakes.

If it's a used bike you'll want to do a safety check BEFORE a test ride.

Good luck on finding the perfect bike...Happy Riding.


Shopping advice and product recommendations are specifically off-topic here.

However, general advice:

Shimano makes products in a deliberate hierarchy of incrementally improving features, weight and quality. The feature you probably want is removable chainrings, so when those wear out you don't have to replace the whole crank.

The FC-M361 is from a higher product line (Acera) than the other two and has that feature (you can see the chainring bolts in pictures online) the other two do not appear to have it.


Cheap solution to vertical bicycle stand

Free wood from pallets could easily be fashioned into racks that can be fastened to the wall with butterfly bolts.  Also, consider looking for solutions at http://www.bikehacks.com/


1976 peugeot 10-speed bike correct tire pressure?

First, and especially with a tire that old, check it for wear.  If it's cracked and dry-rotted, replace it.  If there are visible rips in the sidewall, also replace it.  If neither of those are the case, look at the sidewall of the tire.  Most tires should have a PSI recommendation molded in the rubber of the sidewall somewhere.


Oil/Anti-seize on outside of nipple when building a wheel?

Threads are a locking mechanism. The issue is simply the threads are easily damaged and do not properly tighten. They can distort from over tightening, crack ect. To say anti seize does not lubricate is nonsense, that's exactly what it does. It allows the threads slip, tightening properly. The pops you hear removing the nipples are the threads gripping each other and your torque is wasted twisting the spoke instead of loosening the threads. This happens when tightening them as well to a lesser degree as they have not had time to corrode together. The nipple is hard to turn but part of the force is wasted on friction and not all the torque is spent on tightening the spoke. To over come you need to waste a lot of energy and again, risk damaging the threads. Not every lubricant is gooey or slippery in your fingers. Ever heard of brass?


There are a number of reasons you could be cramping - if that is, in fact, what it is.

You are not properly warmed up before exerting yourself
You are exceeding your limit of fitness
You are not properly hydrated
You have not eaten enough food to fuel your ride

Without additional information it's really hard to diagnose something like this, but those are some common causes of cramping during a ride or any athletic activity. You may also look at your technique to see if you are favoring one side over another or have a setup that is not ideal.


Treacherous ride - top half of fork points backwards, but the bottom points forward

After a little Google research of this bike, you can see that the fork is assembled correctly. What's going on is that the crown (the part the stanchions attach to) is bent/twisted or the steer tube (the tube that runs through to the handlebars) is bent. Either way, you're going to need some mechanic work or a new fork.

On a side note, you can probably remove the stanchions from the crown, but judging by the amount of rust in your pictures, they're probably fairly stuck by now.


Is the use of wide fatbike tires problematic with 100mm BSA bottom brackets?

The math is easy to do.

According to Sheldon Brown, fatbike chainline is 66 or 76mm for dropout spacings of 170 and 190mm respectively.

Assuming a 100mm BB is used with a 170mm dropout spacing and 66mm chainline: a 5" tire is approximately 127mm wide so the tire would extend 63mm off the centerline of the bike.

That's only 3 mm clearance if the chain is running parallel to the centerline of the frame. With the chain on the largest ring it's conceivable that the chain would hit the tire.


Does a brand-new bike bought online need a service before riding it?

I took the bike to another bike shop.

The man there adjusted my handle bar (apparently when I did it myself, it was not good enough, not straight or aligned).

Then he put the bike on a stand and checked gear shifting to all the gears.  It all worked fine.

He also pointed out the slight rattling noise I heard is caused by the chain rubbing against the front derailleur.  This is normal and can be corrected by "trimming".  This YouTube video explains "trimming" the front derailleur.

The man said the bike is fine to ride.  I asked him when I should get it serviced, he said: "in 3 to 6 months, depending on how much you ride."

He also said not to put any lubricant on the chain because the factory has already done that.

I was in the shop for 10 minutes and he didn't charge me anything, even though I was more than happy to pay him for his courteous and informative service.

Clearly this is the shop I'll take my bike to for the next service.

So to answer my own question, it's advisable to have a professional check out the bike before you ride it, unless you're experienced with bikes yourself.  You don't need a "service" per se.

Like with all new products, one should study the owner's manual before thinking there's something wrong with the product.  I should think the owner's manual discusses "trimming".


If you're replacing the whole crankset and BB, then any 9-speed double crankset should work. The chain width for 9-speed systems is the same for all makes (not the case for 10 or 11 speed).

But before you do that, I'd look around and see if you can replace just the left  arm. Any crank designed for the Shimano "outboard bearing" BB should work (those are the ones that clamp onto the BB spindle with two pinch bolts). Just make sure the crank arm is the same length.


What are common causes of premature chainring wear?

Why do you wear chainrings quickly?
Cross Chaining - If you tend to be in the big ring on the back and the big ring on the front at the same time, you're probably doing it wrong. Same with running the small ring on the front with the small ring on the back.  This can cause uneven wear on the front chainrings due to the awkward angles the chain must bend. This can wear the sides of the front chainring teeth and make them more pointy.
You are riding dirty or don't lube up first- If you ride offroad especially, your chain can get dirty. If your chain is not lubed properly, it can cause extra friction. Keep the chain clean or it will work like sandpaper, wearing down your chainrings and make sure you use the proper type of lube for your environment. Chain wear tends to deform the inside surface of the gap between teeth, making an uneven 'U' shape between teeth.
Riding with an already "stretched" chain - If your chain is worn, It has a different shape, which is going to cause extra wear on your chainrings. If it's worn too much, you can only really replace it.  Running with a "stretched" chain is probably worse than running with a worn chainring.

If it's a pretty new bike and the chain is well maintained, I'd probably blame it on cross chaining. Be aware of your riding style and make sure you're not overextending the range of your front chainrings.


Should I get a reflective jacket/coat, or more lighting and reflective strips for the bike?

While the obvious answer is that you really should have lights and a reflective jacket or vest, I'm assuming this is the real world and you have limited resources! Let's go by what conditions you ride in:

If your route is mostly well-lit and being seen is more of a requitement, I'd concentrate on a decent cycling jacket or safety vest. I prefer uninsulated jackets, but I also have one that's lightly insulated; I sometimes wear the safety yellow jacket over the black insulated cycling jacket. You can also get small, cheap LED be-seen lights you can clip on your helmet or wear on your head if you don't wear a helmet.
But if you ride in the pitch-black, I'd suggest a cheap safety vest, making do with a non-cycling jacket you may already have, and put the rest of your money towards a good light, something like a Dinotte or a MiNewt. They aren't cheap, but they're worth every penny.

One final point:

Reflective gear and a good headlight are more than just safety equipment, they're good PR. I get compliments on my safety equipment, particularly my 200 lumen headlight, quite often, from people in my town (often parents with children), drivers (more than once, someone at a red light will roll down a window to tell me my lighting and safety equipment are uncommon, and keep it up!) and once from two New York City cops (who yelled out "that's the way to do it!" as I rode by at night).

Yeah, the idiot wrong-way "ninja" cyclists make us all look bad; but cyclists with safety equipment make us all look good.

Whatever you decide for now, keep in mind that this isn't an either-or choice in the long term: As I'm sure you know, you can always get more safety equipment later on. Yeah, it may seem as if those dinky lights don't do much, but when you have a lot of them, they make you quite visible indeed.