Why are there metal shavings in my brake pads?

This is normal to some extent - brake pads have to be made of soft material which wears down on the rims (and conversely, the rims wear down into the brake pads to some extent) in order to stop you. This means the pads pick up grime and bits of metal from the rims and road and stuff which embed into the pads and in turn wear down your rims / reduce braking efficiency. If they're eating large portions of metal, then you should probably switch the pads to ones made of different material (anecdotal evidence suggests the pads which come with most cheaper brakes belong in the trash).

I'd start with a high quality pad (e.g. Koolstop Salmon pads), and making sure the rims are clean (use citrus degreaser/rubbing alcohol). Mavic and some others make special blocks for cleaning and (slightly) sanding your rims as well, which you can use (but definitely not necessary).

If you do get metal or other contaminants in your pads though, you can pick it out with tweezers and buff the pads with some fine sandpaper (remove the grit afterwards!). Make sure the pads have sufficient material leftover after this - if the metal backing comes through, your rims are going to take damage.

Also, make sure your brakes are properly adjusted: http://sheldonbrown.com/canti-trad.html
http://www.parktool.com/blog/repair-help/cantilever-brake-service is a good link to look at as well (Specifically see the "Pad Wear" section). If your brakes are rubbing on the brake tracks, you'll pick up more cruft (and wear out your rims), for example.

Also, check your rim wear indicators (if you have them - they're reasonably common on modern rims) to make sure that you're not too worn on the rims as well (this is typically a little groove which should be there on the rims, but can appear in other forms such as something that appears when the rim is too worn out). If you don't have them, you can try a procedure like http://archive.ctc.org.uk/resources/Magazine/20011163.pdf. If the rims get too worn, they break and you end up hurt (probably).


how can I fix an uneven hydraulic disk brake set

In my view its unlikely the entire brake needs replacing, although if you have to pay someone for the time needed to resolve the problem, its entirely possible it will be the cheapest solution in the end.

As already said in comments, the most likely cause is contamination of discs and pads with brake fluid. If the pads have been cleaned, the next step is to replace them and thoroughly clean the disk.

Another possibility is the shop replaced the pads with new ones. In this case there are a couple of possibilities. It may be the new pads just need to be bedded in, and the problem will resolve itself with a half dozen high effort stops. You may also need to replace the pads on the other side with a matching set as different pad material have different characteristics.


Never used a repair stand before. Wondering how much they can handle

The load limit is determined by the stand rather than the clamp in all but the cheapest setups. If you look at what bike shops use they tend to have great big chunks of steel with clamp arms bolted to those. But those clamps, even the really good ones, cost about the same as a cheap clamp with stand. So the question to ask right at the very start is whether you're better off buying the proper tool right at the start.

In both these photos (search for "bike mechanic" rather than "bicycle workstand") the key point IMO is that there's a nice solid bit of steel pipe holding the clamp up, and if you look around that pipe is normally bolted to the floor. Where I worked we used slightly thicker square tube with a clamp each side (two mechanics per pole).

 (via Boston News)

 (via JobMonkey)

That setup will be more expensive that a cheap portable stand, but a lot more effective. Find a local steel fabrication business, tell them what you want, say you're willing to wait until they have time to put one together, and it shouldn't cost too much. Most places will be able to make it from offcuts, and it's an easy welding job. What you want is thick wall mild steel square tube somewhere between 70mm and 120mm on a side and 5-10mm wall thickness, between 1.5 and 2m long. Weld that to a bit of plate about 400-600mm square and 8mm-15mm thick. The reason for the loose dimensions is that you are aiming for "what spare bits do they have", if you specify it exactly they will cut it for you and charge accordingly. So that post will cost between "some beer" and "$300 plus tax", depending.

I used to use a simple length of square tube with the clamp on it, and I'd put that in the vice on my workbench. But that was a 6" engineering vice that weighed 30kg, bolted to a 100kg steel framed workbench. If you have a bench like that it's a great way to get an easily moved out of the way stand.

 (via Mσᶎ's awesome Paint skills)

A stand like that will hold an electric assist loadbike without problems once it's bolted to the floor. With a bigger plate you can avoid bolting it down, but it might fall over if you don't pay attention (and it's heavy enough that if it falls on your bike it will seriously damge the bike, or you). Lifting a heavy bike into the stand, on the other hand, will be a hassle. My local eBike shop uses powered hoists for that reason.

A cheap stand will be very flexible, and even if it doesn't actually collapse, it will feel as though it's about to even with a lightweight road bike in it. When you want to apply any real force to the bike you will need to brace the bike against that force as well as applying it. Which is a huge pain. That said, they do work for most minor repairs and adjustments.

But the stand is cheap and it folds away to nothing. Hopefully when you want it to fold, but for that price you can't be too fussy. What you're buying there is light and easy to fold, you're not paying for a usable workstand.

A better lightweight design is this style:

They support the bottom bracket rather than the top tube/seatpost, so there's less stand to flex. It's slightly more twiddly to get the bike in and out, but they're easier to work with in my experience. At least for upright bikes - it's unlikely that a recumbent or load bike will fit into them at all.

edit to add:

Finally, many "bike storage systems" actually work ok as workstands. The ones that suspend the bike from the roof using pulleys are very close to the power hoist that my LBS uses. Many of the "arms poking out from the wall" style have arms long enough that you can pull the bike out a bit and spin the pedals while the bike is on the storage unit. This style of leaning hanger is available pretty cheap if you can put up with less decorative versions:

With the "wall hook" style that hang the front wheel it's less convenient, but you can put a block under the bottom bracket to push the rear wheel away from the wall and adjust the gears that way. Reaching the handlebars when the bike is hung up is only easy if you're tall, though, so it's not always an option.

Many car racks can also be used this way.


Nutrition during long rides while reducing fat

Well to start with, you don't just leap from 1.5hr spin sessions to 5 hour rides - unless you have a long history of cycling this would most likely not end well.

However, to answer the nutrition question:

While you are riding, there is a limit to how many calories you can absorb.  Most sources will quote 60-75g of carbohydrate per hour (240-300kcal per hour).  You will want to choose an energy source that is mostly carbohydrate, although a small amount of protein can protect muscle mass and improve recovery.

Over a 5 hour ride this will add up to in the region of 1200-1500 extra calories, which may seem a lot, but will still be less than you are burning.

As you become more experienced with this type of ride, your body will adapt to use fat as its primary fuel source and you will find you are able to gradually reduce your energy intake should you wish to do so.


Transfer components from a Scott Spark 20 to a Orange Alpine 160

They are not even vaguely comparable.

The Scott Spark is a short travel XC bike, and the Orange Alpine is a big burly enduro bike.

An enduro bike will need a longer fork as a bare minimum, but even if you move over the rest of your components, will not behave anything like an XC bike in terms of pedalling or handling.


Suntour derailleur compatibility with shimano shifter

This is going to come down to the cable pull ratio: that is, how far the derailleur moves sideways for a given cable pull from the shifter.
Suntour hasn't made derailleurs for decades, so it will be hard to find experiences using them documented online. Based on this discussion, I would not be optimistic. The cassette (or possibly freewheel in this case) will only complicate matters further, since the distance between sprockets will also determine how well your setup shifts.

All derailleurs do not behave exactly
the same way. Why should they? Suntour requires a different amount of
cable pull compared to Shimano to move the same amount of lateral distance
across the cogset. Specifically, Shimano derailleurs require about 10% more
cable travel to achieve the same amount of movement across the cogset than
Accushift. So the mixed marriage of Suntour and Shimano may sort-of work
over 5 cogs or so, but eventually the cumulative error at the ends of the
cogset will cause sloppy shifting.


E wheel needs an 8sp free wheel instead of cassette

This is difficult to answer without more information.

8-speed freewheels were made, although not for very long. They'll be hard to find and will be "new old stock" if you do. 7-speed freewheels are still being made, mostly for low-end bikes.

However, if your bike has 8-speed indexed shifting, it's not going to work right: The gears on a 7-speed freewheel are spaced 5 mm center-to-center, on a Shimano 8-speed cassette, they're spaced 4.8 mm. You might be able to fake it if you get the derailleur perfectly aligned on the middle gear, but you'll be 0.6 mm off at the outside gears. Which doesn't sound like much, but the sprockets are only 1.8 mm thick. As always, the late, great Sheldon Brown has the info. If you want the shifting to be bang-on, you're going to need different shifters (or you'll need to switch to friction shifting). If you really want to go nuts, you might be able to disassemble the freewheel and reassemble it with narrower spacers to get the same center-to-center spacing.

Another dimension you might want to check is the hub width. Is it 135 mm? 130 mm? What about the spacing on the frame it's going into?


Are bikes with aggressive positions required to achieve high fitness levels when training on a bike?

TL;DNR - The bike you will ride most often is the bike that will get you fittest.

Fitness and power transfer are unrelated. Your bike fitter is presuming you want to make the most of the power you have, so is suggesting an aggressive position is needed.  This is possibly because people who pay for bike fitting tend to also be competitive riders who want to go the fastest they can with the power they have. These customers are already close to peak fitness, so they are scratching for low single digit percentages gains in 'power to the ground' (1% faster over an hour's riding is 30 seconds – that is the difference between winning and not being in the leading peloton).

If, however, your goal is to get fitter, then a more comfortable position is arguably more suitable. The more comfortable you are, the more likely you are to ride more often and further. If the power you produce is the same on a hybrid at 20km/h as on a fitted racer at 30km, and hour of exercise produces the same results in terms of fitness, it's just that one bike lets you go further. If you are uncomfortable and quit riding the fast bike after an hour vs say an hour and five minutes on the hybrid, the hybrid will get you fitter.

As far as 'Bike fitness', training on a hybrid for a century on a racer would be unwise: your training would be sub optimal as a more upright position uses muscles differently, but that is a discussion about specific fitness vs general fitness.

How much difference it makes depends on you – some people find it demoralizing busting a gut to get 20km/h when they know they can do 30km/h on a better bike, and are better off on a faster bike. Others are happy to dial up a work output and accept the speed they get.

No one needs a 7kg $10K bike to get fit, many think they are fit because they can ride a 7kg $10K bike faster than the guy on the 20kg, $200 BSO. The industry loves selling $10k bikes, hence much of the promotional material around the need for a high end racer.


Adjust handlebar position/height (damaged screw?)

If you find that it can't be fixed, then try to go with a solid stem that's already at the correct angle. I had an adjustable one before and after adjusting it, I could never get it to be tightened properly and it would always wobble.

A bike co-op or bike dump is a good place to look for parts like this as solid stems don't usually wear out and many of them are salvaged from old bikes that may no longer be usable.

Now that I think of it, I'm pretty sure the nut was rounded off similar to yours after many tries to remove the wobble. The adjustable  ones are usually low quality because they are heavier than solid stems, and people who buy more expensive bikes don't mind spending a few extra dollars to get a good fit.


Is master cylinder hydraulic fluid level critical (Shimano)?

The system is designed to have the lever bleed screw displace some oil as it's reinstalled. In other words, the lever end wants to be completely full at the end, and there is not supposed to be an air gap there

In the too little fluid direction, there is some tolerance for an air gap before symptoms begin, but ideally you wouldn't have any. If by chance you finish the bleed and find out there to be a small air gap at the lever, if it's small enough then dripping a little oil in may be reasonable, but usually there's none when you pull off the funnel so if someone does wind up with one, it would first make me worry that something went wrong in the bleed.

If one doesn't have a funnel, then most of the time, doing the "gravity bleed" part of the procedure the same way as with an older Shimano brake works fine, i.e. by dripping in more fluid in the screw hole as the fluid feeds into the catch bag/bottle at the other end. Doing this with road levers would be clumsy at best though, as they tend to often really need to have their angular position changed during this step to free up air bubbles, as per the official instructions.


Most likely the freewheel mechanism in the hub has broken.

Unless you have the knowledge and tools to disassemble the hub you’ll
have to take the bike to a local bike store or mechanic.

If fixing the freewheel is not possible replacement of the whole rear wheel is likely the solution as replacing a hub requires rebuilding the wheel which has a substantial cost.


Inner tubes work over a range of tire sizes.  The difference between 1.9 and 1.95 width is insignificant for the tube.  Go ahead and reuse it.  You can look in the shop at what range the tubes claim to cover.  My quick look at one online store showed two tubes rated for 26x1.5-2.0, which cover your range, and one rated 26x1.95-2.25.  In theory you shouldn't have the last one, but I am sure it would work for 1.9 just fine.


Easiest approach is simply to bend the top in a vice to get it to clear the head set:


Are road cranks less strudy than comparatevely priced MTB cranks?

In general, road cranks are lighter because they use less material than mtb cranks. Mtb cranks use more material so they can handle more abuse. Compatibility aside, I would be cautious in using road cranks for much more than cyclocross duty. You may never have a problem, but do you really want to find out the hard way?


Swapping wheels and cassettes with Shimano GRX 600/800

My experience with swapping wheels is disappointing.
I had to adjust the derailleur (limit screws, cable tension) and rim brakes (due to slight difference in rim width and dish) every time I swapped wheels. Maybe if you have exactly the same hub and rims on both wheels it will work better. I think my derailleur adjustments were necessary because the cassette position was ever so slightly different between the two hubs.
The longer chain should work fine on the 11–28 cassette. After all the small-small combination is the same, so your rear derailleur should be able to tension it enough.


Does valve stem diameter matter for my rims?

Yes, the holes are different sizes. 6mm and 8mm, from memory. The hole size matters if you have skinny rims as 8mm out of a 20mm rim is a lot compared to 8mm out of a 40mm rim. But you already have valve holes.

In theory putting a presta valve in a Schrader-size hole matters, in practice it doesn't.

The base of the valve is where you'll see any effect from having a presta valve in an oversize hole, and in theory the base of the valve will get cut up by the edge of the rim. You might also get dust or water inside the rim if you have a V or box rim.

In practice it doesn't seem to matter. I do this fairly often because almost all my rims are drilled for schrader but I'll fit presta tubes rather than ride on flat tyres). I've seen marking around the base of the valve when I've pulled the tube out, and occasionally it's bulged up 2-3mm.

If you look at the locking ring/nut that comes with Schwalbe presta valves it's got a smooth face under the knurled section that's exactly the right size for a schrader hole, suggesting that they expect people to use them that way.

The ring I'm talking about has an arrow in this pic, and @jimrings found the pic on the right.

There are a couple of other types of adapters. You can see the most common ones in the pic below.

The ones to the right and left push through the rim from the inside and hold the valve centered in the rim. The rubber one on the right actually attaches to the rim. The metal one on the left is fitted over the valve before inserting it into the rim.


You may start breaking spokes in the rear wheel after putting some miles on the bike. That seems to be where the effects of load shows up first.
You can plan to mitigate this by budgeting for a new rear wheel. If this is the bike you are talking about it has 28 spoke wheels. You'll want a 32 or even a 36 spoke replacement wheel, hand built.
You don't have to get the beefier wheel straight away, but when you break a spoke don't bother getting it replaced, more will inevitably follow. Upgrade the whole wheel at that point.


Are Hövding helmets safer than regular helmets?

That's the inflatable "airbag" helmet.  It's main claim to fame is that it isn't really a helmet, but sits in a (dorky looking) collar around your neck until needed.

First off, I'm skeptical that the helmet could be tested to most bike helmet standards at all, since the test procedures would not be designed for such a helmet.  So it's pretty much impossible to say if it "meets standards", much less is better than others. For helmet testing info smf.org/standards/b/b90astd (thanks to @Ken Hiatt)

Secondly, the trigger mechanism can't rely (as a car airbag does) on waiting until impact to activate.  So it must trigger based on sudden movements of the head and upper body.  The reliability of this is questionable.  (Keep in mind that a substantial number of head injuries while cycling are due to simply falling off the bike -- the old "forgot to unclip" problem, eg.)

Third, given the iffy nature of the trigger mechanism, false triggering would seem likely, and having the helmet suddenly inflate in a critical situation could be extremely disorienting and lead to an accident that would not otherwise happen.


Don't integrated headsets wear out, ruining the frame?

Here's an excerpt from Chris King about headset types:

  What is an “Integrated” headset?

  It is a bicycle frame, fork and bearing system designed to eliminate the humble headset cup. To integrate
  means to combine and hopefully to simplify. What has been “integrated” by the integrated headset? The bearings
  now rest inside the frame instead of inside pressed-in cups. All of this trouble and confusion is to remove two 12
  gram headset cups from the front of your bicycle. True, an integrated headset can give the bike a nice, smooth
  looking front end, but the consequences of this change to your bicycle are significant.

  Simply put, the performance
  and lifetime that you expect from your new bicycle will be reduced, most severely in aluminum mountain bikes. All
  bicycle frames that use integrated headsets will ultimately have substantial performance and reliability problems
  due to the inherent flaws in this design. The largest flaw is a bearing system that does not positively attach the
  bearing to the frame, leaving the bearing to “float” resulting in wear and impact damage to the frame.

  As an
  additional complication, each manufacturer seems to be doing their own thing, with no real standardization to date.
  As a result, there are multiple bearing types and sizes (some of which have been discontinued with no replacement
  options) and the frame builders and bearing makers are not all working from the same drawings. Lack of
  standardization is a bad thing for everyone. It means that you may not be able to get replacement headset bearings
  for your bike, and you
  will
  need them.

So, to answer your question, yes, an integrated headset will eventually wear out, but that service time is dependent on riding type, style, number of hours, and quality/material of the frame.

You can read more about all three types: Integrated Headsets Explained


Frame flex. The step-through frame means that the seat tube has a bending force applied to the middle of it, so it has to be stronger and heavier than the same tube in a diamond frame. Usually the down tube is also beefed up. Even so, there will be more flex both laterally and longitudinally/torsionally. I've also not seen a decent lightweight frame in that geometry. If you want light in a step-through design perhaps look at a mixte frame instead.

You can get some seriously tiny road bikes these days (google). The real choice (IMO) is between 650c and 700c wheels. 650c wheels look better, make for a lighter bike and generally have fewer compromises. They are more of a scaled down full size bike. 700c wheels mean the bike looks stretched a little with the rider low down between the wheels. The advantage is that tyres are easier to find and the manufacturer already has jigs etc to build bikes around 700c wheels. Tyres are only slightly easier, these days Schwalbe and others make a decent range of 650c tyres (they're not just a track & time trial size) and shopping online means you can definitely buy them (your LBS should be able to order them in too).

To find one of those second hand I suggest checking out the second hand ads at your local racing clubs. Finding one in the giant mess of second hand bike ads has proved tricky for us in the past, mostly due to the overwhelming number of cheap crappy childrens bikes that pollute the search results. However if you want to sell one just approach short adults... you'll sell it very easily.


Can I just fit a cassette with more gears with the same derailleur?

If you want to change your cassette to something with more gears, then you will need to replace the rear shifter and possibly the rear derailleur.  A cheaper option would be to get a wider range cassette which still has 8 gears.  You'll have bigger jumps between the gears, but you'll have a bigger range of gears.  With a wider range cassette, you may need a new rear derailleur with a longer cage.


Is there a preferred frame size calculator?

IMO Frame size is more than just measurements. A proper bike fitting pairs your riding style & level with the frames own handling characteristics. (defined more by tubing and angles than measurement alone)

BUT... not everyone's out to get a custom bike frame made or go research their frames butted tubing or headtube angles... But I always suggest visiting a place where they know how to "fit bikes" (for racing, touring, etc) and getting advice from a bike fitter.

Don't forget to buy a water bottle and power bar while you're there, chances are they don't charge you for the advice. #smallbusiness


How to prevent over-tightening a bolt with a socket wrench?

Generally, the size and grade of the bolt will indicate its strength and the max torque that should be applied. You can use a torque wrench (they make them rated for inch-pounds and foot-pounds) to set the amount of torque you want to apply to the bolt.
If your bike has a service manual, it may specify the torque settings there. Otherwise, the bolt may have markings on the head indicating the size and grade of the bolt.


My old pedals don't spin freely, is it worth lubing them?

Some pedals don't spin particularly freely from new. This is OK as the friction does not increase with load and is a tiny power loss. Often happens on MTB pedals to get a tight seal to keep rubbish out - after a short time rubbish in the bearing costs more than the seal in terms of power loss.

If the pedals used to spin freely, you possibly throwing away a few watts away as the lack of spin will be friction in the bearings and will get worse under load. Also consider that that friction is probably wearing the moving components faster than they would if well lubed.

Lubing them could be as simple as a drop of oil (wet chain lube) in between the bits that move, or a complete strip and grease.  Personally I avoid the 'complete strip and grease' as I find by the time pedals need that I prefer to save the time and install new ones.

I would go with a drop or ten of oil (left overnight then wiped off) as it will probably help a little and is worth a crack.


How do I choose which kind of shorts to wear for mountain biking?

I wear baggies for non competitive XC. Just like baggies on a road bike is a fashion crime, Lycra and MTB is a fashion crime (unless you riding at national competition level events) :)

I have two sets of baggies - one is stretchy, light, quick drying and surprisingly durable -  think light weight running shorts with Lycra added. As they stretch, they are closer fit than many baggies.

The other is less stretchy and heavier fabric, and baggier(Fox brand), but still not heavy and dries reasonably quickly.

Go to you LBS / Sports shop and shop around. You cannot do this on the internet as you need to feel and see the fabrics.


BMX bikes are all very similar. Short, stout frames, tall handlebars, 20" wheels (and maybe the occasional 24" for a very tall BMX rider), and wide tires. The difference between Supercross and Freestyle BMX bikes is in the gearing. Supercross bikes will have a higher gear ratio for getting up to speed in races, while Freestyle bikes usually have a lower gear ratio to make pedaling easier at low speeds. Some freestyle bikes will come equipped with brake cable gyroscopes, to allow for barspins, but they aren't as common now as they were during the height of BMX's popularity.


Which spokes to get, Wheelsmith or DT Swiss Spokes?

I don't know if this helps, but Peter White is a well-regarded framebuilder and wheelbuilder who has strong opinions on the Wheelsmith vs DT Swiss issue:

http://www.peterwhitecycles.com/spokes.asp
http://www.peterwhitecycles.com/DTspokes.htm

The gist of his argument boils down to two (current) main differences:

1) DT Spokes have a 6.3mm elbow length vs Wheelsmith 6.1mm (assumed) which can accommodate larger flanges, but are undesirable.

2) DT Spokes have a sharper, 'triangular' transition into the head, which has led to more cases of the DT Spokes popping heads off than Wheelsmith, which have rounded transitions.

In addition, there WERE a large number of issues with DT Spokes relating to their specification change in 2001 from 6.1mm to 6.8mm, causing problems with slop in the hub and sharper elbow angles making the lacing more difficult. These have since been remedied and the elbows are now down to 6.3mm, but not back to the original spec and WS hasn't changed their specs around (perhaps this is circumstantial evidence, but it makes WS seem a more steady design than DT).


Setting up chain tension on a fixed gear with road bike frame

The short answer, is you generally cannot make a fixie out of a frame with vertical dropouts.
Not only do you need to tension the chain, but the spacing of the axle of the bottom bracket and rear wheel varies, depending on your selection of cog and chainring tooth counts.
Adjusting tooth counts will allow you to try to fine adjust the spacing, but it won't always get you there. The formula for how adding or removing a tooth will change your ideal chainstay length is not simple. You're removing a link from the chain, but you're removing it at an angle, so your reduction in chainstay length will not be the same as the amount of chain you remove.
Online, you can find many magic gear calculators [example] where you can try to pick a ratio that will exactly match your chainstay length.
You can also use a special half-link chain element, to adjust the chain by half as much as an ordinary link.
With all that said, the difference between "slack" and "tight" is a very small amount of chain stretch, and fixies in particular are pretty touchy for the tension. What I describe above I think works well for coaster-brakes and single speeds, but I would not recommend it for fixies.
If you are especially willing to throw caution to the wind, you could file the dropouts to be slightly wider, which might buy you just enough space to make one of the magic gear ratios work. The risks to safety should be obvious but that's up to you.


When did bicycle chains go back to being bushingless?

There is a book written by Frank Berto titled The Dancing Chain - History and Development of the Derailleur Bicycle. The fourth edition was updated in 2012. On page 368-369 he discusses chain design and chain types. Apparently, the 1981 Sedisport chain was the first bushingless chain. Its main feature was that it shifted better than bush-roller chains and also better than the Shimano Uniglide introduced in 1976. At the time, I guess 5 gear sprockets were the rule. With increasing number of gears over time, the bushingless chain took over from that point.


How much does rider weight increase tire pressure?

As a first approximation you could use zero.

But more accurately, with a 23mm tyre you probably have about 20mm diameter of air inside. A 700c wheel is ISO 622, so has an inner radius of 311mm. So your tube forms a torus with major radius 321 and minor radius 10mm. A litre is a cubic decimetre (a cube 1/10th of a metre or 10 cm on a side) so it's easier to use dm for this. So, major radius = 3.21dm, minor = 0.1dm.

  Volume of a toroid = 2 π² minor² major = 2 π² 0.1² 3.21  = 0.63 litres

Now, at 100psi with a 200lb rider the flattened area is 2 square inches, or 1290 mm². So we want the volume of a toroidal section having that flat area. Conveniently the section is an ellipse, so the area is π (major radius)(minor radius) (and a circle is πr² because both radii are the same). As a first approximation let's say that the minor axis is half the width of the tyre (so 10mm) and see what happens:

  a = π R r =>  R = a / π r = 1290 / 10π = 41mm

That seems a little on the short side, but it's vaguely plausible, so what's the volume? Unfortunately the volume of a toroidal section is a bit beyond my rusty calculus, so I'm going to cheat. A lot.

First, what arc does this represent?

  sine θ = 41/321 => θ = 0.0004 radians (about 7°)

That's about 3.5° each side of the centre of the flat spot.

How deep is it? Since sine X = x for small x, and we definitely have small x, if we go out 20.5mm from the centre of the flat spot we've got a right triangle 20.5mm on the long side. The short side is that times sine 3.5° as above:

  depth = 20.5 * (20.5 / 321) = 1/321 = 0.003mm
            = 0.00003dm (since we're using dm for volume calculations)

As you can see that's a pretty flat shape, so even a crude pyramidal approximation is not going to matter too much (if it's out by a factor of 5 or 10 it's not really going to matter, it's still going to be "roughly zero" as a fraction of the total volume above).

Conveniently we can express the volume of a pyramid as a factor of the area of the base:

  volume of a pyramid = 1/3 height * area of base

The area from above was 1290 mm², which we need to divide by 100² to get it in dm² for the volume calculations = 0.129 dm²

  volume lost = 1/3 * 0.00003 * 0.129 = 1.34e-6 litres

What fraction of the original volume is this?

  fractional change = lost volume / total volume = 1.34e-6 / 0.63
  = 2.12e-6

See, even if that's out by a factor of ten, we're still looking at a volume change of 10-5. So the pressure change will be about the same, a change of 1/1,000,000 the actual pressure.

If this was the XKCD guy's "What If" I'd now work out how fat you'd have to be to cause an appreciable change in tyre volume. But I'm not, so I shan't.


How to know when to bleed a hydraulic disk brake / tips for improving disk brake performance?

Bad disc brake performance is almost always either air in the lines or oil on the pads.

Air makes the levers spongey and oil stops the pads grabbing the disc.

Your problem sounds like air, a bleed should sort it out. A bad bleed from the factory is not that uncommon.

If you've patience you can try turning the bike so the line is as vertical as possible and gently tap the calliper, line and lever to see if you can convince the bubble into the reservoir, this is a temporary fix but will confirm that the problem is air.

An oily pad will feel firm if you pull the lever but will not grab the disc when you're riding. They often feel just fine if you push the bike with no weight on it.

To test this you could pull out the front pads and see if they work better, be sure the clean the disc with some alcohol first.

The easiest way to fix dirty pads is to buy new ones.

Brakes that are not run in properly feel like oily ones, just not to the same extent, and are easily fixed by following the run in procedure in your manual. This is usually getting up to speed and stopping as hard as you can 5 or 10 times.


How far do I “pull over” in a bike lane?

Please don't block the bike lane or traffic or parking spaces, but use your best judgement; in that order.

Personally I feel a curb is a logical and physical barrier which protects you from the activities of the traffic way.

Protection
Getting on a curb means a car that hits you has already been slowed down by a 6 in. cement block applied up to 4 times (4 tires) against the cars momentum. Ever see a car hit a curb? Sure they can plow over it, but they definitely slow down, and change direction. When riding you have several options to evade, but when on foot you are much slower/less agile. Use the curb as a natural defense. Also, I'm not a law expert but I'm sure there are better legal protections for being off the road with regards to this matter.

Courtesy
Do you look everywhere and try to decide what everyone will do before they do it while riding. I sure hope you do, it will help keep you safe if you can anticipate situations, both while riding and while driving. If you remove yourself from the bike lane you become a non-player to those using the traffic ways. The cars don't have to decide if you might fall over while mounting/dismounting/precariously balancing while tying shoes etc. Like wise for bikers, will you see them when you decide to start? How straight will your line be when you do start etc. Even if you pull over far and look before you start up, you have forced others to do the extra work of thinking through possible scenarios and possibly slowing down, changing lanes or changing routes around a block where you are 'pulled over'.

If you are on a long straight away with no intersections and you can anticipate the traffic for the next 2 min, and you will only take 20secs then who cares. If you don't see anyone, but a car could pull up from around the block in less than 10 secs even though it seems dead you should probably just get over the curb.


How to adjust rear brakes on this bicycle?

It sounds like you've really done some good work! The pad material shouldn't be too soft. Soft enough that it creates good friction when pressed against the rim, but still rigid enough that it holds its shape while doing so. Keep in mind they will break in after using them for a few days or a week or too. The pads you have look like they should be just fine, although it's hard to tell from pics, but Kool Stop pads are my favorites and I know they work great, if you  chose to try something different.


I see three possible locations on the tube that could match your description.

On the outside (rolling face) and 38mm across the inflated tube from the valve.
On the outside, but 180 degrees away from the valve (so the opposite edge of the wheel)
On the outside, but 180 degrees away from the valve (so the opposite edge of the wheel)  BUT on the inside edge of the tube that faces toward your hub.  I think this is what you mean.

The first two are the same - there is something in the area that is causing your abrasion.  Like a small wire or glass shard that is wedged deeply in the rubber of the tyre and you can't see it by casual inspection.  Need to flex the tyre inside-out and look carefully.  You can also use the hole in the tyre as a measure around from the valve to see where the damage came from... that will put you within 50mm of the spot.   However changing the tyre would have resolved that.

The third option is the most likely.  Something on your RIM is causing the issue, so changing the tyre did nothing.   Look closely at the rim tape, make sure its laying flat in the channel and that there are no parts of the nipples exposed.  Also that no part of a nipple hole is left uncovered.  These can frett away at your tube over time.  Even paper labels or sand or small rocks can winnow their way through your tube if they are inside the tyre.   Some brands of tyre liners can also eat it at the ends of the liner, but these are normally on the outside circumference only and you probably don't have liners anyway.

The fix for this is to replace your rim tape - its cheap stuff, just make sure the replacement is as wide as your existing tape, or slightly wider but not enough to ride up the inside where the tyre bead hooks are.  Fouling the bead hooks risks a blowoff.

There's a minor chance this is an installation error where you've scraped the tube with a tyre lever while installing, but that's not as likely.

  If none of this helps, do please add some clear and well lit photos of your tube damage, and the area of the rim causing the problem.


I'm thinking it looks a lot like the Hans Lutz logo:

German manufacturer, ex racer...

I'm not sure he made just lugs, for Bianchi at that. So I think you're correct about it being rebranded. Silly really, the Hans Lutz I've seen is nice stuff!

Note the color of the frame too, very similar to that pictured. I can also vouch that the bidon holder mount holes on yours look exactly the same as those on the frame pictured here.


Selecting a front derailleur: parameters

Derailleurs, fortunately have been fairly standardized. Simple specs like these can help you determine what derailleur is best for your bike. Here's a brief overview of some of these:

Maximum capacity: The maximum number of teeth between the largest and smallest rings. eg. 48T-22T = 26T.
Top gear teeth: The range available for the largest ring. Any size ring in this range will work. Even some rings outside this range may work, but not to their best potential.
Cable routing: Derailleurs come in multiple pull types:

Top Swing: The clamp is below the cage and the cage pivots above the clamp. The cable attaches from above.
Bottom Swing: The cage is below the clamp and swings from below the clamp. The cable attaches from below.
Dual Pull: Can pull from either direction.

Chain Stay Angle: The chainstay angle is the angle between the chain stay and the seat tube. The derailleur must fit this angle or risk the cage hitting the chain stay.

Of course, Sheldon Brown has some good information, but if you really want to dive into all those numbers, have a chat with a mechanic at your LBS. I didn't know anything about these angles until my mechanic pointed out that my seat tube angle changed near the BB and meant I should have a bottom swing instead of the top swing I bought. It works, but doesn't provide the best shifting possible.


Since you are already replacing spokes, the easiest way to find out is take a broken spoke from each side of the wheel and measure it. There are no hidden differences, you only need to match the length, thickness and type of spoke head. Note that spokes may be thinner at the center than ends, this is called butting.


Why do some disk brake pads use split-pins or bolts to retain metallic or resin pads?

Some caliper models use the threaded style pin and some use the bent cotter pin type one. Several of the pad shapes are used in calipers of either type. Every Shimano replacement pad that is compatible with a caliper that uses the bent pin type retention pins will come with any replacement pin or pins that may be needed, plural because there are actually 3 length/profile variations of bent pin across Shimano calipers. There is no metallic versus organic distinction involved.

For the most part the calipers that have the threads are the more expensive ones, or at least that's how they've been doing it recently. To date I believe all the road calipers are threaded, but that's subject to change. On all these calipers the pin is considered part of the caliper and is re-used. If they're lost or damaged, a specific replacement has to be obtained; there is some overlap but it's not dimensioned the same across all the Shimano calipers that use threaded retention pins. If the threaded pin is lost or damaged, a bent cotter type one of appropriate length can be substituted without issue.

Neither style is subjected to braking loads in any way. The pin is a loose fit in the hole of the pads. Braking loads from the pad are entirely pushing on the lips of the caliper that the pads rest against. The pins are there solely to prevent the pads from falling out when you're not braking.


What to wear under tights with fabric padding?

TL;DR If it's got a pad, don't wear anything under it. - Benzo

I've owned several pair of cold weather cycling tights, including some that were questionably "cycling" tights because they had no padding/chamois.  I've always found it best to wear nothing underneath when there is any sort of padding.  If there is no padding whatsoever (just a tight) putting a set of bike shorts/bibs underneath is your best bet. For anything with a pad/chamois/additional material, any additional warmth requirements should be layered on top (long underwear, shell pants, rain pants, wind fleece, etc).

In your case, I may consider either getting rid of them in favor of something with a real winter chamois (should be thicker) or possibly try to remove the extra "pad" and use bike shorts/bibs underneath.

Seat fit is a dicey enough proposition without mixing pads and hoping the combination is not worse than nothing.

FWIW Disclaimer:  I wear bib shorts down to about 10F (usually with over baggy shorts or a wind pant up to 40F).  I wouldn't ever wear my winter bib tights at a temperature above 10F, so it's rare that I would ever want to take them off and have something underneath.  I won't ever buy a winter tight unless it has a thicker pad in it.  I'll take all the insulation I can get sitting on a -20F seat.  For that reason I find my lightly "race padded" bib shorts to be inappropriate for actual winter riding.


Using PTFE spray on rear derailleur springs

You most certainly can use a PTFE spray after cleaning, but, I would use a high quality chain lube instead.

I use this dry teflon lube on my drivetrain and use a precision applicator to lube my derailleurs after I clean the drivetrain.

Personally, I wouldn't use any WD40 branded lubricant on my bike.  Also, I'd recommend not using a spray type applicator to apply lubricant on small parts.  I like to use the precision applicator, i.e. the long, skinny straw, to be able to reach into all the pivots of the derailleurs and accurately apply the lube.  The spray can be messy and will often contaminate other parts of your bike, like rotors or brake tracks on your wheels.

The 'Dry' lube is nice because it doesn't pick up that much road grime in the derailleurs.


Step 1

Clean the derailleur pulleys by holding the blade of your screwdriver against the sides of the pulleys and turning the crank. You can do this with the wheel in the dropouts, or with the wheel removed.

Step 2

Brush the dirt off of your derailleur using a combination of brushes with bristles of varying length and stiffness, like the ones in the Finish Line Easy-Pro Brush Set.

Step 3

Degrease the derailleur using Finish Line Speed Clean, a powerful degreaser that dries almost instantly. You won’t have to wait before applying lube, or worry that the lube will be broken down by excess degreaser that didn’t dry.

This is also a good time to go over the pulleys again. First spray down the jockey pulley with Speed Clean while turning the crank, then take your rag, hold it between your thumb and forefinger, and pinch the pulley while continuing to turn the crank. Any dirt that didn’t come off on the screwdriver blade will come off on the rag. Repeat with the bottom pulley. This is most effective if the pulley is still moist with degreaser when you run it through the rag. Because Speed Clean dries so quickly, ensure this by spraying down only one pulley at a time, so that the bottom pulley doesn’t dry before you’re done with the jockey.

Step 4

Lubricate the derailleur by first spraying it down with Finish Line Dry Teflon Lube, then injecting Extreme Fluoro, a fully fluorinated grease, into all points of friction.


Can bicycle parking stands damage wheels?

I guess it partly depends on the wheel/bicycle. Smaller, sturdier wheels (e.g. 26"/559mm MTBs) should be more resistant. With road bikes I’ve observed that they often lean on the spokes. This is especially bad if you have a low spoke count and therefore a high spoke tension which makes the spokes even less suited for lateral loads. I think it can definitely damage your wheels if it’s especially gusty wind or someone stumbles and runs into your bike really hard. Usually it’s also hard to properly lock your bicycle (since you often can’t put your back wheel into the stand if you have a rear derailleur), leading to the sad event displayed in your second picture. I don’t have disk brakes but I could imagine that you could damage them on some stands as well.

I try to avoid such stands whenever possible.

As a personal anecdote, my dad and I used to transport bicycles on a car trailer using a stand like the one in your first picture. On one occasion we apparently hadn’t tied the bicycles down hard enough and the constant vibration and rubbing completely destroyed the sidewalls of my road tires.


Where to find bolts for an old Raleigh Bicycle?

I spent my formative years in a Raleigh Five Star Dealership that just so happened to buy up all of the vintage Raleigh mudguards of the steel type for 26" wheel 3 speed bikes. (Raleigh had a warehouse clearance.) That was in the UK and we had mudguards for everything going back to AFTER the requirement for the white panel on the rear mudguard. Nothing from the the 70's onward had the bolt type you describe, although we also had a lot of frames including ones with the 7/32" x 26 TPI eyelets. Sounds to me that you either have a U.S. special, something really obscure, something really, really old or something after-market.

I suggest that you put some new mudguards on there. It will be a lot less hassle.
For those new mudguards you can drill out the existing holes or use 5mm nuts and bolts, obviously with a fair few washers in there.

If you want to keep the retro look of the existing mudguards, you could make your own 'P' clips with a bit of tin, some snips and a drill. These could then be attached with a metric nut and bolt.


Since you have 700C/ISO-622 rims and you're doing pavement riding, I'd recommend one of the Conti "Gatorskin" tires. They go up to 32mm wide-- which is nearly optimal for urban street riding and nicely adequate for occasional trails w/o mud.

These are very popular as training tires for roadies (in narrower widths) because they're very resistant to flats caused by glass.

Handling will be different in "feel", but nothing that you can't get used to in 10 minutes of riding.


Because of the tilt of the seat tube, this setup does not make for efficient pedaling. The seat is sitting over the center of the rear wheel, which moves your entire center of gravity too far to the back. You want the center of gravity to be a bit ahead of the bottom bracket, where the downward force is applied to the pedals. That's one of the two main reasons for the aggressive position: that forward center of gravity. The other reason is aerodynamics, of course.  I suggest creating a zig-zagged seat tube:

This is just to convey the basic idea. Any good pro shop can make the required ground shadow adjustment that must accompany this modification, and other necessary details.

Huge bonus: This seat post is guaranteed to absorb road vibrations better than even the nimblest vintage 1970's Italian road bike frames.


How to practice SPD release in very steep uphills?

Practice, practice, practice... You need to move the physical motions of getting out of the pedals from your conscious muscle memory to your unconscious muscle memory. Once it becomes an instinctual unconscious reaction, you'll have far fewer problems.

A flat grassy space is good for this. Try doing track stands and un-clip to catch your balance.

Or you can just ride and eventually it will become second nature. The more you practice, the quicker that will happen. I don't ever think about unclipping, it just happens when I want it to. A lot like the actions of driving a car, do it enough and you don't have to think about it. I can't remember how long it took me to get there, but it will happen eventually.

The one gotcha that still remains is that it can be very difficult to unclip when your weight is still on the pedal. You can get good, but there will still be times
where clipless pedals aren't as escapable as flat pedals.


Does tire pressure matter when the bicycle is in the trainer?

Like car tires, bike tires can lose some pressure at colder temps (see: Why do tires "lose" air during the winter?) although I'd be surprised if your 'cool' room is cold enough for this to be a significant factor.

More likely, you are just seeing the normal slow loss of air pressure that bike tires experience all the time.

Since your trainer is a relatively "controlled" environment compared to a road, tire pressure is of less importance than it is on the road.  If your tire is under-inflated you really don't need to worry about a pinch flat or the tire coming off the rim as you corner.  Conversely, if it's a little over-inflated, you won't suffer bone jarring bumps or benefit from lower rolling resistance.

At worst, I think you might experience some accelerated tire wear.  Of course, my trainer seems to eat tires no matter what pressure I run my tires at...

Sheldon Brown has a nice write-up about Tire Width and Pressure which you might find interesting even though it doesn't specifically discuss tire pressure when using a trainer.

Edit:  I overlooked the What pressure would be recommended? part of the original question...

To me, the answer to this depends on what tires you are using.  My current tires have a maximum pressure of 120psi and I run them at around 100-110psi.  In the summer I check my tires and re-inflate before every ride due to the various reasons I've listed above.  In the winter, I only check the tires occasionally as there is minimal drawback to riding a trainer with under-inflated tires.


Are there any non-Shimano Hollowtech II compatible cranksets?

Of course, but be aware that there are patents (for the design) and trademarks (for the name Hollotech 2) applicable and the compatibity might be in two separate aspects.

The first aspect is the compatibility of the cranks and the bottom bracket. Here it is enough that the crank spindle of the correct 24 mm diameter and the right length. FSA Megaexo 24mm cranks are often reported to be compatible with Hollowtech II bottom brackets. However, that probably does not help you with your powermeter and also, some say they can be up to 24.07 and hence not compatible. There is also Rotor3D 24 mm. So they are all 24 mm, but manufacturing tolerances may cause some problems.

The other aspect is the connection of the left crank to the spindle. That may be applicable for powermeters that are sold on a left crank. I fear you are out of luck here. If you have a Hollotech left crank, it must go on a Hollowtech II spindle. Also, be aware of the road/MTB difference here, for example this left crank powermeter vendor has a disclaimer about that and about XTRs. The interface is covered by Shimano patents, the name by Shimano trademarks, and is not, to my knowledge, produced and sold by anyone else.


Shifting direction is different for front and rear shifters

The reason why shifting is arranged this way:

Shifting to a larger chainring at the front gives a higher gear ratio, shifting to a larger sprocket at the rear gives a lower gear ratio.

Shifting to larger chainring/sprocket requires positive pulling force from the shifter whereas shifting to smaller chainring/sprocket can be done with derailleur spring tension. It's intuitive that getting the chain to  climb up onto a larger chainring/sprocket will takes more force than letting it fall down.

Its easier to get positive pulling force from the thumb shifter lever then the finger lever, there's more room for a longer lever and a longer lever throw. The thumb can travel on longer distance without the  hand losing grip.

The exception is of course Shimano's Rapid Rise rear derailleur which use derailleur spring tension to shift to larger sprockets. THis obviously didn't work as well as 'normal' derailleurs as the type has disappeared.


Reattaching fork to mountain bike - What is the correct assembly order?

There are a number of different schemes for fork headsets, but this seems pretty close to what you have:

Here is a different image of an older design, but with the same basic components, and a little easier to understand.  What's called the "crown race" in the first image is called the "bottom cone" in the second.

And this link may help you understand things a bit better.


Why do disc brakes stop faster in dry conditions?

No, the stopping distance is not just traction limited - or at least not just by the wheel/road surface combination. Even if you can block your wheel with your rim brakes and get the wheel slipped, you might be able to stop faster with better modulation when you actually avoid the slip. The consistency in breaking in the disc brakes helps to predict the exact force necessary.
Also, the raw power is definitely bigger, there is no question about it..


Look Keo pedal no longer floats. Can it be fixed?

Put some soap on the cleat contact points to lubricate it.
Be careful not to get it everywhere, just in case it becomes too floaty!
This assumes you have covered a bunch of other options (of course!)

The cleats are actually the same and you didn't mix-n-match (some other manufacturers make compatible cleats which might be slightly different)
The black protruding insert is not different / damaged / inserted incorrectly.
All the caveats above regarding dirt etc.


Online spin classes with a smart trainer

To the second part of the question, there are a number of apps that use smart trainers. You use two. Training-oriented apps like Trainer Road or Sufferfest or virtual worlds like Zwift, Rouvy, and RGT take your power from a smart trainer or an on-bike power meter, or an estimate of your power from a trainer's resistance curve. The former class of app is mainly interested in your power, although it may control a smart trainer's resistance to simulate climbs where you need lower cadence, high-resistance efforts, or to do ramp tests (which estimate your power around your VO2max, and then estimate your functional threshold power from there; these tests involve ramping up the power until you can't pedal anymore). Virtual world apps move you through a virtual world, and they will vary smart trainer resistance to account for terrain.
I don't use Peloton. My understanding of Peloton bikes, based in part on this article by DC Rainmaker, is that they do measure your power, but they do not broadcast it over ANT+ or Bluetooth, which are the two open source protocols that just about all cycling devices use. Additionally, Peloton bikes have controllable resistance, but because they don't use the two transmission protocols I mentioned, a different app can't control them. So, a Peloton bike will be inherently less flexible. That said, someone is using Kickstarter to fund a device that could render a Peloton bike controllable via Bluetooth. (In general, we don't give product recommendations, so this isn't a purchase recommendation. Additionally, not all Kickstarter projects succeed, and you usually get left empty handed. Or they could succeed with a lot of delays.) If this device or similar ones came to market, this could render Peloton bikes more flexible. Peloton doesn't seem to have an incentive to re-engineer its hardware to broadcast over the common transmission protocols.
Approaching the question from the other side, we could ask what inputs Peloton classes take, or perhaps what inputs the standalone Peloton app takes. I am not certain. It does appear that you can use the app on any spin bike or even a real bike (although presumably not on the road). Mom Tech Blog seems to imply that the Peloton app can be run without any sensor input, e.g. heart rate or cadence, at all. The app may not be designed to acquire sensor input and transmit it to the instructor. Sipping and Shopping, another blogger, described how workouts often rely on a certain cadence, and she got a cadence and speed sensor for her spin bike. She used them with the Wahoo app. However, again, I'm not sure if your cadence from a Bluetooth cadence sensor would be transmitted to the instructor. You might not get personal call outs from the instructor this way. This might or might not impair the experience enough for your wife to be dissatisfied. It does appear that the app may have a short free trial period, as do all the apps I mentioned in the first paragraph. Also, you can manually change the resistance on your smart trainer from its own app, so this might help you stay in tune with a Peloton session better than a regular wheel-on trainer.
I'd speculate that Peloton is aiming at a different market than the cycling-oriented apps. Peloton might never really feel the incentive to integrate external sensor input into their own app. Many dedicated cyclists would probably weigh the cost of the Peloton bike against a road, mountain, or gravel bike, a premium set of carbon wheels, or something else. That said, I don't know Peloton's breakdown of profits and losses by segment, but I would guess that the subscription part of their app may be more profitable than the bikes. Bikes, after all, are mechanically complex and require service and maintenance. It's possible they might decide that modifying their app to take external sensor inputs could be a potentially profitable move, or at least a relatively low-risk one. Feel free to prod them on social media.
In terms of live classes, I know one cycling studio near where I live. (NB: I'm linking them as an example, not as a recommendation.) Their business model has centered on in-person indoor training, coaching, bike fitting, and other services. I don't think this business model is that common, but I suspect it's not unheard of, at least in areas with a big cycling community. This store has done a lot of online classes during the pandemic. It's possible this segment of the market will grow and will offer live but remote classes for people who don't want to be there in person. The rationale for this is that the indoor segment is much more conducive to structured training. For instance, I don't believe I have a segment of uninterrupted road or bike trail where I can reliably perform a 2x8 minute FTP test - I can get there very early in the morning such that almost nobody is present, but there's simply not enough road. For competitive but time-constrained athletes, structured training can be more time-efficient than unstructured training.


How does one revitalize chrome lugging without harming the finish of the paint?

In the UK I've had success with Brasso, a cloth and lots and lots of elbow grease. Don't apply it with anything so harsh as wire wool or a scourer, just the impregnated wadding that comes with the product.

Unfortunately Brasso in the states is a slightly different composition so I can't vouch for it's efficacy.


The main advantage is more hand positions. With a regular flat bar, you hold your hands at the grips (with possibly about one more hand position available if you have bar ends).

With drop bars, you can hold at:

The brake hoods (on top of the brake levers)
The drops (the bottom part of the bar)
The tops (on the left and right of the stem)
That place between the hoods and the tops
Possibly others (or less of these, depending on who you ask).

For long rides, this makes a difference due to hand fatigue.

A secondary advantage is you can also change how aerodynamic you are and your body geometry with respect to the bike by shifting around and using different hand positions relatively easily. For example, when you're in the drops, you're in a more aerodynamic shape versus sitting straight up with your hands on the tops.

Drop bars aren't for everyone and do require proper setup (as do all bikes) and acknowledgement of the geometry of the bike. In particular, racers will likely set their bike up differently than tourers will (e.g. higher bars than racers), where its primarily a comfort thing. If you like doing long rides with flat bars and bar ends, more power to you. But for most people, the same bike won't work well with drop bars and flat bars because changing the bar changes the riding geometry.


Replace Brompton folding pedal - what tool is needed?

If it's a pre-2012 non-titanium Brompton, it takes a 24mm socket.  If it's a 2012 on-wards, it needs an 8mm Allen key.  The 2009 to 2012 titanium Brompton used a 10mm Allen key in a Ti pedal bolt.  The official Instructions are available on Brompton's site.

Very important: remember that the left hand pedal is left-threaded -- the reverse of normal.

Note that pedals can get quite tight.  A standard 8mm Allen wrench might well not be enough leverage.  An 8mm Allen socket combined with a larger  socket wrench is a better tool.


Shimano Deore XT: is 9-speed no longer continued? (Europe)

Shimano has a pretty good track record of wear parts availability for older groupsets. I am using 8-speed myself, and there are several European mail order stores as well as local shops that have spare cassettes and chains.  I would expect that 9-speed spare parts aren't going away either.

The problem with off-road groups is that rear derailleurs are not compatible between 9- and 10-speed, so you need to change shifters, derailleurs, cassette and chain if you need to switch later.

EDIT: To clarify, even though 9-speed XT groups have not been sold in a while, XT-level 9-speed wear parts are still available. For 8-speed it looks like spares above Deore/Tiagra level are no longer available.


What features should I look for when buying bib tights?

This is a somewhat subjective topic as everyone has their own personal preferences.

But for me (a skinny 30 something riding in Scotland where winter is typically -5 to +5°C):

Fabric: Generally a thick 'roubaix' style brushed lycra for warmth.  Windproof fabrics tend to be less flexible/comfortable and I would only use them in extreme cold weather.

Padded: No. You can wear your existing shorts under non padded tights.  If they have their own pad, they need to be washed every use, without a pad the tights can be re-worn after some rides.

Straps: Personal preference.  Some prefer the higher waistline and extra material for warmth.  Personally I prefer easier natural breaks as riding in very cold conditions makes them a more regular occurrence.

Water resistance: I find DWR treatment an amazingly good feature on tights, with splashes from puddles just bouncing off, keeping you much drier and warmer.  Softshell type materials (which are also usually coated) will be even more water resistant, but have their own drawbacks (covered above).


What is the most secure bike rack for long distance travel?

The most stable and secure racks are the ones which mount directly to the vehicle at hard points, such as a trailer hitch (for rear racks) or door frames (for roof racks).

Racks which use fabric straps attached to hooks can move around a bit more, and if they are not very well made, they can loosen over time.  This problem is made worse by the fact that most cheap racks use fabric straps.

Of course the best is if you can somehow mount your bike inside your vehicle.  If you drive a small car this won't work, and even some rack mounts may not be viable if your car has only two doors.

Personally I prefer roof racks, and have driven up to four bicycles at a time on multiple cars using them for hundreds of kilometers without stopping, at speeds up to 125 kph.  The main problems tend to be (1) the removed front wheels spinning in their separate mounts (easily corrected by small straps which some racks now come with), (2) reduced fuel efficiency and increased wind noise, and (3) the possibility that you will wreck your bikes by driving into a garage or other low-clearance area.  All of those problems are reduced on rear-mounted racks.

If your car has a trailer hitch, consider a rack that mounts in it.  These can be very secure, low-noise, and easy to install and remove (both rack and bikes).  The main downside is that accessing your trunk becomes less convenient (but still not as bad as with rear racks which attach using straps).


What types of mountain bike handle bar grips are available and how to they affect comfort and handling?

Which grips you get for a mountain bike is mostly a matter of comfort and personal taste.

In terms of how they attach to the bike, there are grips that glue on and grips that screw on. They're exactly what they sound like. Locking grips (that tighten onto the bars with an allen key or a screwdriver) will avoid the grips twisting over time.

You can also get "ergonomic" locking grips. I had a pair of these and found them quite comfortable, and again, this is a matter of personal preference. (I also found that they reduced fine control just a little bit.) Some even come with smaller barends built-in.


Old 6 speed casette on a new modern wheel

The old "cassette" is most likely a freewheel. You can see the difference between a cassette and freewheel here

So no, I don't think you will be able to use the old freewheel on the newish wheels (they probably take cassettes). You can just buy a new cassette though (they're cheap), assuming what I said was correct.


Options for what to do if the star nut is spinning?

To resolve this situation, there are several options each with advantages and disadvantages (ie risks)
In my personal case it was a combination of multiple causes

The star nut hadn't been quite hammered home far enough, so the second line of "leaves" was still on the outside of the tube,
The tube was an aluminium handlebar that had been trimmed short.  So the internal wall thickness increases toward the center, unlike a bent steel handlebar.
The ID had been reamed out in the past to try and give more space for clamping the old rubber handlebar mount, but only to a depth of about 20mm.  The starnut had got to that lip and not gone any further.
Due to a turn in the bars, the mounting bolt was a little too long, and ended up threading through the starnut and bottoming out.  This pushed the bolt end sideways before it was tight, forcing the starnut back out a little, giving it less purchase on the walls and then it was free to spin and grind the inner walls of the bars without backing out.  I had locktite on the threads too, which didn't help the bolt to backout, even though it had not set.

Answer:

If you can't get the bolt to undo and you can hear the starnut turning, attempt to lock up the starnut by pulling it sideways, and twisting.   Assumes the topcap is not squashed down onto the steerer.
Another suggestion was to gently "crush" the outside of the tube so it constricts the starnut.  However this would be immediately fatal for a carbon part, really bad for an aluminium part, and only has a chance of succeeding with steel which will probably be permanently deformed by this action.  I didn't even try this.
If there's some level of bolt outside the top cap, you might get lucky by hammering it into the steerer, to help seat it enough to resist the bolt's undoing torque.
Decide what's more important or harder to replace, and use a drill to remove the other thing.  Drilling through the bolt cap would let you save your top-cap, or the mirror's arm in my case.
Once you can see the star nut then there are many more options.

Simply seating it further into the steerer tube will probably secure it nicely.
Do inspect the ID for scoring though - if its cut badly then this steerer and probably the whole fork is toast and needs replacing.
If its a straight steerer, you may choose to drift the starnut down and out the bottom of the fork.  Though this will likely ruin the starnut.
Lastly, you can use a drill bit and drill driver to shred the core of the starnut.  Once sufficiently thinned, the whole thing should fold up with long pliers and drop out by gravity.

Here's the bolt that had to be thinned and rethreaded to fit the starnut.  It was originally an M8 bolt for a motorbike.

Here's the starnut after it had been hammered home properly - there's a good 5mm of overlap now.  I also gobbed in a lot of epoxy to help lock things down, and then cleaned up the threads with an M6x1.0 tap.

Other options that I didn't try:

drilling through the bars to offer access to the starnut.  I felt this would weaken the bars even more right at the point where it was scored.
Trying to feed something in from the other end - with a steerer tube this might have worked, but mine was a wiggly set of bars with no real access.  And the other side had a star nut in it already.

One Month Later
The starnut failed internally after I whacked the mirror on a railroad crossing while negotiating a chicane.  The threaded core came loose from the two spring-steel "flowers"
I tried peening the flange to resist movement, but spring steel isn't malleable.  I considered epoxy but that was going to be hack.
Since I had a spare, the only fix was to remove the whole thing and replace.
I drilled out the core's flange, using a 9mm twist drill at an angle so the core wouldn't rotate.  Once they were sepatate, a 10mm twist drill caught the first spring steel flower and pulled it right out.  An M6 bolt in the core and a crowbar was enough to yank the the core out.  The inner flower got pushed well into the handlebar and is now unreachable around a curve, so there it stays.
The replacement starnut got scratched up with a file, and then I slathered the entire thing with 2 part epoxy before hammering home like the previous one.   The epoxy should help resist the rotational forces.
Future?  If it fails again, I will turn a ~20mm plug of aluminium, drill and tap for a M6 bolt, tap it into the bars and pin in place through the bars, under the bartape.  I might even contemplate using a left-handed thread for the main bolt.


What is a simple mnemonic for remembering the thread direction when removing pedals?

What could be simpler than remembering that the left-hand pedal has left-hand thread?


What is the most effective way to upgrade my Cervelo S2?

To get faster times, your options are:

Accelerate faster
Cruise faster
Decelerate faster

To accelerate faster, reduce rotating weight and increase bike & component stiffness. Reducing non-rotating component weight will not have much effect unless your races involve a lot of climbing, especially as lighter components are usually less stiff unless you're swapping cheap alloy for good carbon fibre.

To cruise faster, reducing drag, rolling resistance and drivetrain friction will help, in order of impact. Your body and clothing are currently the greatest contributors to your drag, especially since your frame doesn't use round tubes, has internal cable routing, and your rims are deep. Rolling resistance can be decreased by increasing your tyre width, since you're not racing on perfect surfaces (such as wooden velodromes). The current fashion in the pro peleton is 25mm.

To decelerate faster, use soft-compound brake pads. Reducing rotating weight also decreases the load on the brakes.

This review of a bike which I think matches yours lists the weight as 8.08kg. This isn't bad, and losing 1.3kg to get down to the 6.8kg UCI minimum will be far more expensive than eating less and riding more to lose body weight.

Things I would consider upgrading:

Tyres. Easy upgrade, quite cheap.
Chainset. The Praxis Turn M30 crank is about the same weight as Shimano Ultegra, but is surprisingly stiff. Praxis make a matching bottom bracket for most shells, including "old-school" BSA threaded 68mm shells.
Stem. Thomson Elite X4 is heavier than their X2 "road" model, but you'll struggle to twist the stem and the 4-bolt clamp is nice and wide.
Carbon bars, but not a superlight model, since you need them to be stiff for acceleration.

Of course, you still need to train more.


I can't find my skewer that came with the trainer. Can I use my bike skewer?

I wouldn't. You'll damage the skewer you have, which will make it unreliable on the road, if not unusable.

Basic skewers with plastic on the nut will certainly be damaged, the plastic gets crushed and then you can't use it. Even skewers with more expensive metal parts will be subject to forces they weren't designed for. If a nice skewer should be damaged in this way, that is more expensive than the right trainer specific part, it is a false economy.

I should have your LBS order in something suitable


Claud Butler Tandem - add a front derailleur?

You may have a few troubles with the curved stoker seat tube, front derailleurs can be remarkably tricky to set up correctly. You can find some more useful experiences here. In particular, you may have to experiment with some low cost parts before committing to something pricier as your choice of chainring sizes will determine where along the curve the derailleur must sit and so what effective angle it will be mounted at.
The maximum allowable chainring size will be determined by the length of your bottom bracket spindle and the clearance of the chainstays. Either crack out some geometry or try it out. It's always tricky to work out chainlines on older parts!

In answer to your second question, your best bet is to have a look here and compare the measurements they have to your frame with a pair of callipers. SJS sell the Thorn tandems so always have a good range, you may have some luck with Tandems East if SJS can't help. Although they don't list the sizes they do offer custom EBB inserts (from the US, at a high cost I expect).


As long as your choosing a 9 speed Shimano shifter for the rear and triple shifter for the front you'll be fine. That's basically everything in the Deore lineup, as long as it's 9 speed. Obviously you'll want to stay away from 10 speed shifters and dont try to mix and match Shimano derailleurs and SRAM shifters or vice versa.
Though you didn't ask this, what may be a more important concern is how your bike is going to fit when you slap flat bars on it. Road bike frames are shorter in the effective top tube than mountain bikes are due to the fact that a straight handlebar decreases reach compared to a drop bar. Your bike is going to fit pretty darned short if you do a flat bar conversion which can cause comfort problems of it's own. There are other fit issues to be considered when doing a flat bar conversion on a road bike, but in my opinion this is the big one.


Tracking down issues with brakes can be difficult.  If the brakes are spongy feeling initialy and pumping them firms them up then you probably have air in the system. if that's the case then it will be a bad bleed or the seals or possibly the brake hose but working out which is often down to luck. If they just have no power it could be contaminated pads.

If it was me then I'd do the following, give the system are realy good clean and finish off with disc brake cleaner if you have some.  Next I'd re-bleed the brakes (having first pushed the pistons right back) and then fit new pads.  Use the brake somewhere safe and then inspect everything to see if you can spot any leaks at the levers, hoses or calipers, take the pads back out and check for contamination with brake fluid.

If you do have a leak then you'll need to replace the seals and/or hoses that have failed - this can be tricky if it the caliper seals that have gone. Getting hold of spares can also be an issue.

It may be easier and cheaper in the long run to replace the brakes. Shimano Deore are relatively cheap and very efective.


You don't need a chain tensioner (by this, you presumably mean something like the Surly Tuggnut and not a pulley which will snap on a fixie). This article from Lennard Zinn (or equivalently, the one he cites from Sheldon Brown) covers how to tension your chain.


Left crank cracks when the left pedal is pressed

If it is an older 3-piece crank, and if you feel play on the left-side downstroke, then it could certainly be a loose cotter, but it could also be that the bearing cap needs to be tightened in a tad more.  I have an older 3-piece crank (w/ loose ballbearings) and I've had to do that before, especially after an overhaul when things tend to loosen up after a few rides.

Of course, there are many types of bottom brackets, as explained here:

https://en.wikipedia.org/wiki/Bottom_bracket


Single Speed / Fixie - Chain tension / uneven tension

I'm going to disagree with Mike and say that chain is far too tight. I race singlespeed MTB and have a fair amount of experience setting chain tension. In the fixie/singlespeed world; a loose chain is a fast chain, but not TOO loose. There is a "Goldilocks" tension to chains where the chain can freely move up/down along the drive line but not enough to jump teeth on the cog or chain ring.

All chains will "stretch" over time and require periodic re-tensioning but a chain that is set too tight will exacerbate wear on cog, chain ring, and the links.

FWIW, I run oval chain rings on my MTB and those are even more finicky to set up. Tension is set on those when the oval portion is at its widest position on the y-axis, then goes slack through its rotation, but never slack enough to de-chain or skip teeth.

Just an example of my chain after a race earlier this year where you can see how slack it was but still connecting and putting power to the tire.


When changing to another crankset , do I need to change to the brand's specific bottom bracket?

It appears that all 1x Shimano XT cranksets are Hollowtech 2, two piece cranksets which require outboard bearing bottom brackets specific to Shimano's Hollowtech 2 system.  Shimano's compatibility chart points out that 1x drivetrains require different frame spacing.  The rear dropouts of a compatible bike would be 142 mm or greater, allowing space for the larger number of rear sprockets.

If your mountain bike has the more common 135 mm spacing between the rear dropouts, you could use one ring of a compatible crankset. There are several tips for doing so on this site and others.

To answer your question specifically, yes cranksets require a specific bottom bracket, especially so the new offerings from SRAM and Shimano and others.  The Suntour xcm utilizes a cartridge bearing bottom bracket with either square taper or Octalink spindle interfaces. The 1x XT crankset utilizes a different type as described above.


how to go from front suspension to full suspension?

You have a "BSO" and as such is built down to a price.  A bare full-suspension frame will cost more than that whole bike, and no guarantee the parts will move over.

I suspect you're a teenager?    Your best bet is to just ride your new bike.  Develop endurance and leg power and aerobic capacity.  While you're riding, look at other riders and learn.

Even though you call it a "cheap bike" its still worth looking after.   Store it inside at night and not out in the rain.  Tune it up occasionally, and don't biff it around.   Lock it too.

In 3-5 years you can decide to replace it outright with something that you've saved up for - so budget to save 10 euros a week and in 3 years you'll have over 1500 euros to spend on the bike you want.  By then your legs should be fully grown so the current bike frame will be too small.

And be grateful that someone bought you a bike, even if its not exactly what you wanted.


Is it poor technique or physiology that causes people to cycle with their knees sticking out to the side?

Based on the people I've seen riding, knees-apart is a symptom.

New rider - it takes time to develop a good pedal stroke, and some people haven't got there.
Saddle too low - If your position is really bad, then the knees instinctively separate.  I have no idea why - try riding a way-small bike.   Relates to....
Posture - riders who might remember the Moon Landings might be expecting to sit up quite straight (ie Dutch-style bikes) where the back is almost vertical.  To do that on a modern hybrid bike needs a low saddle, which encourages the knees apart.
Fear of falling - Saddles can be set down by riders who want to put their whole foot flat on the road while stopped.  Yes this is a saddle-too-low, but the root cause is poor balance, or a perception of the same.
Beer gut - I was over 100 kilos when started riding seriously on a road bike, and to use the drops I had to be standing out of the saddle, else the belly and the upper thighs tried to occupy the same space.  Even a minor tum will affect the upper thigh and where the skin folds to the lower tummy (technical term anyone?)
Thunder Thighs - related to the stomach one above, but simply lower.  If the rider's thighs are a bit thick, then repeated rubbing on the sides of the saddle's nose may be an irritant and drive their thighs apart.  Chaffing is no fun.
An unfortunate choice of clothing?  I've done rides where something wasn't sitting quite right, and to alleviate irritation have sat up or rearranged things like seams.  This would be a more temporary situation.
Moisture - poor clothing choices can build up sweat in all sorts of places.  Dampness could also come from rain or from road water and poor mudguards/fenders leading to damp clothes.
History - riders who have come from a MTB or BMX background may be subconsciously prepared to stick a foot out and dab.  That's where they do a light touch on the ground to help with balance on a corner.
Speed - Sitting up and spreading yourself out catches more air to slow you down.  If you're going too fast then this is one way to reduce speed.  Again, more subconscious than planned.

Have I missed any?

Balance - I know I've used my knees like a motorcyclist on a turn, to vary my "lean" quicker.  Probably not pedalling at this moment though.


Neil is right, most all "auto shifting" or "ghost shifting" is the result of cable-tension problems.
If the cable is a bit loose, the derailleur will try to shift "up" to a smaller cog.  If too tight, it will try to catch the next larger cog.
Cables stretch, especially after a short period where the new cables stretch to the point they're stable.  after that, they should be good for a long time.
Try this.
Shift to the highest (smallest) cog and try to pull the derailleur cable away from the frame.  If there's a lot of slack, it's too loose.  If it feels very tight....
With either condition, make sure the shifter is in the highest position, and loosen the cable at the derailleur and then pull it snug.  Re-tighten the securing bolt and run it through the gears; it should be very close.
Ideally, the chain should jump smartly to each cog both up and down, and seat solidly on the cog.
If it's just a bit off, you can play with the barrel adjuster either at the shifter or at the derailleur.
Another cause of such problems is a bent rear derailleur "hanger", the part that the derailleur attaches to.
Some of these are very soft aluminum and can be easily bent.
Make sure the derailleur cage is exactly parallel to the cogs and the hanger is not visibly bent.


Chain really quite stretched, should I change cassette at the same time?

The easiest way to tell is simply to install the new chain on the cassette. If the cassette is worn from the old chain, it will skip when you apply a decent amount of pressure (standing up will usually do this in your big ring and half way down your cassette). If it does jump, you'll need a new cassette. It's really as simple as that.

I would be surprised if you need a cassette. The lower model cassettes are made of steel and don't wear easily. (My current cassette, a Shimano 6700 is now 12,000 miles. I change chains about as often as you did and I do keep it well lubed).

You may notice a bit of noise when you change chains. I notice this also and it usually goes away after some mileage. If not, you can always try adjusting your rear derailleur a bit to see if that helps.


How to adjust cable length on integrated brake/shift levers, when there is no barrel adjuster?

If there's no barrel adjuster, then you'll need one installed. Ask LBS to do that or do it yourself:

Get an inline barrel adjuster and two 4mm ferrules. These are pretty cheap.
Get tools to cut cable housing.
Make sure there is enough shifting cable left to accomodate extra 3-4 centimeters added by adjuster. If it's too short, get a new cable.
Detach cable from derailleur.
Find a straight section on cable housing that doesn't rub anything and mark it.
If your frame runs cable bare and not through inner liner, attach a long string to cable end before pulling it out. This will help to route cable back.
Cut housing in marked location, install ferrules on both ends. If ferrules have long tongues, cut them down too.
Adjust the adjuster to shortest position, install it in the cut.
Route cable back using the string. Now you can tweak cable tension for front derailleur.

The result should look something like that. As a side note, 5800/6800 derailleurs have more complicated installation procedure than older models, make sure to download dealer's manual and read carefuly for instructions.


Is the 30 teeth chainring on Campagnolo Mirage 52/42/30 crankset replaceable?

The bolt circle diameter for recent road triples is 74 mm, which allows something around 23 teeth. Looking at the catalog of Specialites TA, their smallest chainring is 24 teeth.

In addition to triple crank, you will need a triple compatible front derailleur and very probably a long cage rear derailleur. There are multiple discussions about chain capacity on this site, search for them.


Could you reduce the weight of a Santa Cruz Chameleon down from 12.82 kg to 10kg (2018 model)?

Breaking the rules with a kind-of non-answer and personal opinion, but...

1) Mountain bikes should be heavier than a cyclocross bike. It's got a suspension fork and frame and wheels need to be beefier to handle bigger loads and impacts.

2) Don't buy a bike with a plan replace major components. Just buy the bike that meets your needs in the first place (in this case a bike lighter than 12kg out of the box). Doing so will be much, much cheaper than swapping out parts.

Another way of stating (2) is: there is only one component you need to swap out for a lighter alternative - the bike itself.

I note the higher level SC Highball S hits your weight goal.


Go to your local bike shops and ask them about group rides, local cycling associations, that sort of thing. If there's not one really "local" to you, find the best one you can find in your part of the state.
The ACA runs organized tours that you could join. Obviously money is involved. They may also know of some other resources.
There are other tour operators that run tours on the TransAm route.
Crazy Guy on a Bike has a listing of community resources, and if you haven't checked out that website in general, make yourself a nice pot of tea and get comfortable.
Finding someone to ride with is not going to be easy, since not only do they need to be able to take time off at exactly the same time as you, they also need to share your daily distance goals, interests in going off-route, ideas about where to stay, where to tarry, etc. I'm not saying you shouldn't try, but be realistic about all the factors involved, and don't be too put out if you come up dry. Joining an existing tour may prove easier.

I rode the Southern Tier solo. It's entirely doable that way, although I'll admit it got lonely at times.


How tight should the tandem front chain be?

The sync chains should always be tight enough that they're not physically capable of falling off, and there shouldn't be any easily perceptible droop, ideally in any rotational position. If you pull the chain up and down, it should have a little bit of flex and "give" to it, the feeling of the pins having some aggregate movement to give in their inner plate bushings. Some sources like to give specific amounts of free movement that indicate a properly tensioned chain, but this is the wrong approach because it depends on the length and the internal clearances of the chain. Too tight is when you can feel any binding or extra friction. Sometimes parts with poor concentricity or damage force compromises where there may be some spots with slight binding/friction. On a nicer bike like this one would hope not, but it's not the end of the world.

Incorrect chainline will encourage dropping in a sync/singlespeed chain capable of it. But mostly the right answer is the chain shouldn't be capable of it, and if it is then problems are likely.


Looking for alternate pants with 'snaps' around calf and/or shin area

For next to nothing you can install snaps on any pair of pants you want:

There are kits with anvils and presses and others with plier-type setting tools. Both work well and both are cheap. I'd suggest trying it out on a similar piece of material so that you can get a feel for how they work.

Here is a link for a cheap kit ($4.92 USD!)

If you're looking for more adjustability, you can sew velcro right into the cuff of your pants as well. (And while you're at it, you can buy reflective piping and reflective ribbon to increase your visibility.)


How to improve/restore vintage Peugeot bike, or is it even worth it?

This is often called "the slippery slope of knock-on upgrades" which can get expensive  quickly.

There are two simple and relatively cheap upgrades to try.

Replace the brake pad inserts with modern compound Kool Stop.  They will brake better than the original ones, which may also be a bit hardened with age.  There will be a model that fits your brake pad holders.  A relatively invisible upgrade.
Replace the bartape with something a bit nicer.  I think you've got the thin nylon strap stuff, and its come away from the corners.  Try some new modern material/retro style.  You might choose to remain with white to match the brake levers, or a more dirt-hiding black to match the saddle, or some other colour that appeals.  But wrap it properly and it will be more comfortable.

If you change the wheels to get aluminium braking track rims, then the brakes may not reach - modern wheels are 622mm and yours are probably 630mm or maybe 635mm.  This would mean new brakes, which may mean new brake levers as well as new tyres and tubes.    See how the knock-on effect works ?

Other option is to sell it on and buy a more modern bike.  Someone would love to own that loverly `80s beauty.


How many spokes can break before I need a new wheel?

The spokes support the wheel under compressive load. The rim in itself is relatively weak in compression. Of course, losing a spoke means that the remaining spokes have to carry increased load and you risk breaking more spokes or buckling the rim beyond repair.

(Note: minor buckles can be removed through "truing" the wheel, a process of adjusting spoke tension to pull the rim in both the axial and radial directions so it is round and straight again)

Recommendation:

Have a bike shop assess whether the rim has been damaged from riding on 3 less spokes. If they deem it is still usable, then they can replace your spokes (possible more than just the 3 which broke) and true the wheel if necessary.

Further reading:

There are some interesting websites that consider analysis of a spoked wheel:

Spoked wheel analysis

Bicycle wheel stiffness


Can I replace this bearing? (MTB head tube)

It's the most common kind of threadless headset. External cups, caged bearings. It uses a 5/32x20 retainer (bearing size x count), which again is the most common type and available online and at most shops for cheap. If you want you can also use loose 5/32" balls, which is more of a hassle but slightly better for headset longevity because you get more contact area and loose balls migrate around more freely and reduce pitting.


Calorie burn information is dramatically different between Strava IOS App and Cyclemeter IOS app. Which is more accurate?

RANT - Do not read if you do not want to be offended.

A lot of calorie burn questions popping up at the moment. The problem is biometrics has become the latest fashion accessory, and everyone (manufacturers and users) are clambering on the band wagon without stopping to think what they want this data for. Manufacturers want to sell gadgets and make money, users are buying into the marketing hype. Ask yourself why do you want to know how many calories you burnt exercising? So you can justify the cream doughnut you are about to stuff in your mouth, or because you are an ultra endurance athlete struggling to main high enough calorie intake, or something in the middle?

RANT OVER

Calorie burn can only be accurately assessed in a lab by measuring your O2 intake and output and calculating how much O2 you burnt. A very close approximation is a power meter, especially if used in conjunction with the results from a lab test. The reality is we are all born different, and just like car engines, some of us are more efficient than others, some idle less efficiently (Basal rate) and some  produce power more efficiently. To cap it off, how efficient we are depends on the food (car analogy - fuel) you put in.

A usable, but not great approximation for calorie burn can be achieved by using a heart rate monitor, your weight and height, and the results from max heart rate test ideally including a V02Max test, and tables collated by measuring lots of people of different shapes and sizes and presuming you are average (Keeping in mind the average person is not average).

Given this complexity exceeds the capacity of Marketing people to comprehend, they simplify it to a point its useless. If you buy a device and it claims to tell you how many calories you burnt, you can believe it - but if you continue to believe after a few minutes of research, I bet you also believe the earth is flat and man never landed on the moon. If you don't believe me, ask yourself how the above apps account for wind in their calorie burn calculation. Do they ask for you bike weight for hill climb calculations?

However, the equipment is useful (if you are a bore at parties) - if gives you  a number you can brag about.


Drivetrain wear -- questions on chain elongation and skipping

According to Park Tools:

  A worn chain shifts poorly and wears sprockets at an accelerated rate.
  The CC-3.2 is a go/no-go gauge designed to accurately indicate when a
  chain reaches .5% and .75%, the points at which most chain
  manufacturers suggest replacement. For 9 and 10-speed chains, replace
  chain just as the gauge fits the 0.75% side fits flat into the chain.
  For 11 and 12-speed chain, replace as the 0.5% side fits. The CC-3.2
  is long, accurate and features permanent measurement markings.

The 0.5% - 0.75% answers when you should replace the chain but does not answer the max stretch before skipping.

Sheldon Brown's site ( http://www.sheldonbrown.com/brandt/chain-care.html ) indicates things get dramatically worse once the elongation reaches 1.0% because at that point it is every other link that is load bearing... so I would assume >= 1.0% is the answer with the variance being attributed to the condition of the cog.  Checkout the link and you will learn more than you can imaging on chain-cog engagement.

  The best way to determine whether a chain is worn is by measuring its length. A new half inch pitch chain will have a pin at exactly every
  half inch. As the pins and sleeves wear, this spacing increases,
  concentrating more load on the last tooth of engagement as the chain
  rolls off the sprocket, thus changing the tooth profile. When chain
  pitch grows over one half percent, it is time for a new chain. At one
  percent, sprocket wear progresses rapidly because this length change
  occurs only between pin and sleeve so that it is concentrated on every
  second pitch; the pitch of the inner link containing the rollers
  remaining constant.