You might have bought the wrong width chain. For road bikes/fixie there are two possibilities. These are the width of the chain.
3/32" and 1/8"

a 3/32" chain will not fit on a 1/8" cog but a 1/8" chain will fit on a 3/32" cog (but with extra space around the teeth).

If it is the length of the chain you are talking about then get a new chain. but the pedal cog might also need to be replaced.

More economic route might be buying a used rear cog (be warned this might be unsafe if you end up riding a lot wear will be faster)


A bike 18 months old is very unlikely to have a friction shifter.  Did you mean its an older bike that you bought 18 months ago?

Raise the bike off the ground, either in a stand or hang it from a tree branch or rafters by rope.  Then slowly pedal with your hand while pulling on the inner gear wire whereever you can get to it (front downtube is normal)

You should see the Rear Derailleur move through its whole arc of motion and the gear change should happen.  This would isolate the problem to your shifter's mechanism.

If the gear change doesn't happen, the problem is at the back.

Consider posting some photos once you've had a closer look.


Difference between Road/Mountain Hollowtech II Bottom Brackets?

I'm going to limit this answer to Shimano Hollowtech II BBs as per the question. Some other brands do it a little differently.

Mountain external bearing crank spindles are longer than road spindles, and their respective bottom brackets are sized to fit one or the other. Shimano BBs have a plastic sleeve joining the two cups that protects the bearings from water dripping down from the seatpost opening and other contamination. That sleeve is a fixed length, so that if it's to be used the cups have to be that far apart from each other (give or take a tiny margin for variance from the exact nominal shell width, i.e. 67.95mm). This isn't the only potential problem with mismatching mountain and road, but it is the first one that will stop a bunch of the potential hack-type workarounds involving adding or taking away spacers from being able to work.

In the beginning, when external cranks came out, road bikes mostly (BB30 existed in nascent form) all had 68mm threaded ISO shells (70mm for Italian) and mountain had either 68 or 73. E-type (bracket-type in the nomenclature of the image below) front derailers and chain retention devices also have to be accomodated by MTB bottom brackets, which is done by keeping the drive side cup thinner than it could otherwise be and running a spacer if they're not being used. (E-type front derailers and many chain retention devices mount clamped in place under the right BB cup.)

Road external cranks and their bottom brackets don't use any spacers between the cups and the shell. Mountain external cranks have longer spindles and the bottom brackets generally come with spacers to accommodate both 68 and 73mm shells, each with or without an E-type front derailer or chain device under the cup. You're using some amount of spacers in all configurations other than 73mm + e-type FD or chain device, and the chainline stays the the same, regardless of shell and spacer configuration. (Complicating matters is that I believe there are some Shimano mountain BBs that don't have seperate spacers for e-type or chain devices, but still do use 2.5mm spacers to adapt for either 68 or 73mm shells.) And road chainline is a different, smaller number, again the same regardless of ISO or Italian.

(From Shimano service instructions for many external MTB BB models)

What can be made to work presuming a willingness to forego the plastic shield (which actually does a lot of work) and/or add spacers not supplied is another question.

To be clear, a 68mm shell is the same on both a mountain and a road bike, and, other compatibility issues such as chainring clearance and chainline notwithstanding, either type of crank with its associated BB can be installed on a 68, say for the purpose of putting a road crank on a hybrid to make it more "road" or a mountain crank on a road bike to make it more "touring". 73mm shells require mountain cranks.

To put it all another way: Say you've got a road crank, a mountain BB, and a 68mm shell. If you install the BB into the shell as intended, you'll find that the tip of the spindle poking through the left cup is inadequate to clamp the left crank onto, because it's physically shorter than a mountain crank. If the shell was 73mm, the situation would be exactly the same, although you would have used fewer spacers to get there. If you tried not using the spacers, the physical length of the plastic shield would keep the cups from being able to torque properly against the shell. If the situation were reversed, say a mountain crank, road BB, and 68mm shell, if you install the BB as intended than you have excess spindle sticking out of the BB. If you add spacers under the cups to take up the slack, the plastic shield becomes too short to fit inside and doesn't do its job properly.

The thickness of the external parts of the cups themselves, measured from the shell contact to the crank contact, is also not the same between mountain and road. Road ISO is about 11.2mm and mountain is 10.2mm. I believe the reason for the difference is that road handles its two different shell width (68 for ISO and 70 for Italian) by having the Italian cups be 1mm thinner in this dimension. Mountain handles the different shell widths (68, 73, plus the need to accomodate e-type and chain devices) by allowing different spacer configurations.

Some other companies, namely SRAM/Truvativ, work differently because the plastic shield slides within the cup, creating a situation where the same Truvativ/SRAM Team GXP for ISO is the generic replacement BB for almost all SRAM and Truvativ external bearing cranks for ISO threaded shells, mountain or road. It comes with two 2.5 mm spacers to be used in the case of a mountain crank on a 68mm shell.


I'm presuming you mean any shifter with a downshift thumb button and a trigger type index finger upshift release, i.e. most Shimano shift pods.
The hoop you must jump through here is that there aren't tons that are 2x8 by design. Most are 3x. Running a 3x shifter on a 2x front crank can be made to work acceptably, and many bikes have been set up that way, but getting it dialed great so that "shift lock" situations are properly unattainable can be a little tricky. Given that you have the option, I think just getting a native 2x shifter is better. One option for this would be the SL-M315 set from Shimano. That's the only set I'm aware of that has the clicks you're looking for and is a matched set.


Is there any advantage to using pedal straps over clipless pedals?

The biggest benefit I see is convenience.  You can just hop onto a bike with whatever you're wearing at the time and go.  Not a big deal if you're planning a 15 mile ride, but a real big deal if you're riding around the neighborhood, hopping off to run into a few stores, etc...

It's also possible to pedal on the flip side of the pedal and get moving without the cumbersome and slow start up that is required to get into clipless or straps.  In an emergency you can even stomp on the straps and move the bike out of the way.  It's rare, but occasionally you find yourself standing there and just want to get out of the way, in any direction.

I've now switched almost entirely to riding clipless though.  Between that and riding fixed gear, it makes the bike feel so connected to me.

To compare:
Straps are easier to get into.
Clipless are easier to get out of (really!).
I've never pulled out of my clipless pedals, I have broken a strap (no big deal if you're not in a sprint).

At this point if I'm riding any distance at all, I change shoes.  If I'm just going to the store to pick up groceries, I don't even have straps, just old school pedals.  The middle ground for straps just evaporated for me.


Can I replace my Shimano Nexus 7 with a Nexus 8 hub?

Depends what roller brake model you have.

Looking at the Shimano 2015-1026 component line up document you can see what components work together. (Very useful current line up web pages here, with links to PDF docs for previous years.)

You presumably have a Nexus SG-C3000-7R hub. That should be paired with the BR-IM81-R, BR-C6000-R, BR-C3010-R or BR-C3000-R roller brakes.

The Nexus 8 is the SG-C6000-8R or SG-C6010-8R hub which works with the BR-IM81-R
or BR-C6000-R brakes only.

The PDF doc is very long, but you can search for the product numbers to find the Nexus 7 and 8 sections.


How suitable is a Dahon folding bike for Indian road conditions?

Unfortunately, I think this bike would be a poor choice for a number of reasons.

First, the small wheel size will accentuate the bad road
conditions. Larger wheels will seem to smooth out the bumps a bit
better.
As has already been commented, folding bikes in general do not handle particularly well, which is not what you want on bumpy streets.
Although this bike folds, that is the extent of its portability.
The Dahon website says it weighs 31.7 pounds, so it's going to be
difficult to heft even though it may fit a bit better on a train
than a non-folding bike.
My experience with Dahon is that you pay quite a bit for the
foldability. It looks like this bike costs $300. When you consider that $300 is the starting point for "bike-shop brand" bicycles, a $300 folding bike is, frankly, using probably the lowest quality components possible. Not ideal for any riding environment and made even worse by rough roadways. I suspect this bike will cause you quite a few maintenance headaches.

I don't know anything about trains in India, but if it is possible to bring a non-folding bike onto a train there, I think you will be much better off overall. You will get more bike for the money, probably a lighter bike, and definitely larger wheels. My advice would be to shop around for something of the non-folding variety if your budget is $300. I would look at a mountain bike if the roads are extremely bad, but for more weight savings a hybrid would be an option.

I don't know the bike shop situation in India, but the folks at a bike shop will probably be able to guide you to something that is appropriate for your local riding conditions.


Yes, a 1×11 is a reasonable setup, especially if you live in a flat area. The weight savings is not that big of a deal, and I would not get a bike just because it had 1× setup if there were a 2× bike that seemed like a better option in other ways.

The theoretical ideal gearing setup would give you a broad range with the difference between each gear being a consistent percentage that's not too big, not too small. Say, 10% steps. This is not really possible because the steps in bike drivetrains are "chunky": all steps need to be an integer number of teeth, so some steps will be too big, some too small for this ideal.

The tightest 11-speed cassettes are 11-25: that spacing is super-tight, and mostly for racers. 11-30 or 11-32 cassettes are typical, and give you a reasonably wide spread. You can go wider (there are 11-50 cassettes) but the steps start to get so wide that it may be hard to find the right gear at any given time. One of my bikes has a 2×11 with 46/30 in front and 11-32 in back: I never shift out of the big ring, and very rarely use the biggest or smallest gears in back, riding on terrain with rolling hills, to give you a basis for comparison.

There have been cassettes made with a couple of extra-low bailout gears for hills, or one bailout gear and one super-high gear, but these are uncommon (they were made especially for the 3T Uno) and not all freehubs can fit a super-small gear. In any case, when you're riding fast, having closely and evenly spaced gears is more important than having one special gear for the jump to lightspeed.

It's worth coming to terms with gear calculators so you can understand what works for you and make more informed decisions. This one is the best one I've seen, because it gives you a visual sense of what's going on.


Tube constantly getting punctured near the valve

I would bet this is caused by a tire with rubber that got "old". This tends to happen to MTB tires that are repeatedly ridden on mud, and I had some tires with this behaviour before.

The problem seems to be insuficcient friction between the rubber and the rim around the bead, specially on those tires with a material resembling fabric on that region (like it seems to be your case, judging by the first photo), and are worse on the front tire since it applies traction only while braking - the rotational force is always applied in the same direction.

One measure to take, as already mentioned, is to put a higher pressure on the tire. It might allow you to get home without damaging a spare tube, but it's not the ideal solution since the slipping tendency is still there anyway, and sooner or later the tire ends up slipping, most probably when you don't expect.

One other measure, that actually works very fine, is to "reactivate" the rubber on the groove where the rim and the tire "seat" against each other, considering that:

In tires with old rubber, many times the said surface is "shiny", or "glassy", or "vitrified", or "mirror-like";
In tires with fabric in the bead, the rubber "disappears" with use, and the slippy underlying fabric is left to make contact with the rim.

Both conditions contribute for the slipping due to reduced friction coefficient. So, to REACTIVATE the grippiness of the material, you should:

Take the tire from the bike and wash it with plenty of water until it is completely wet. Since the tire is off, you can wash the rim either;
Brush the bead groove vigorously with a properly-sized brush, applying some abrasive soap mixed with water. Mechanics soap could be great but maybe too violent. I had excelent results with toothpaste (seriously!), and even with glycerin soap without abrasives. In any case, adding water enough to get a good foam is much better than just rubbing the dry product on the rubber. Rinse repeatedly after this with pure water, aiding with the brush;
Optionally, at last you can apply those products to make car tires "shiny". These tend to somehow protect the rubber from getting dry and glassy again.
Important: assemble and inflate the tire while it is still wet.

I had tires almost unusable because of this slipping problem, and the problem disappeared like magic after performing these steps.

As an additional fact, any modifications I tried to make in the rim (cleaning, sanding, filing, grooving) had no effect.

Hope this helps!


To answer my own question, I purchased the tires. It's simply a case of inconsistent labeling. The 27x1 tires are effectively 700x22.


mechanical disc brakes and bikes with internal cable routing

All mechanical disc brakes should have compressionless. The total pad travel distance is something like a fifth or a tenth of what it would be with a rim brake. Any length change of the housing is amplified in terms of waste lever travel by the same amount. Spyres and Spykes are good brakes, but using spiral housing on them can create problems that a caliper design can never solve, especially with routing schemes that require tight bends. Tight bends make the problem worse with spiral because an air gap is opened up between the coils at the bends, which then eats up lever movement before braking force is applied to the rotor.
If spiral housing is used, the power loss it creates and lever movement it wastes will be worse the more of it there is. And, as above, many full housing, internally routed bikes have some tight bends. That's what the ad copy is getting at. There's nothing wrong with using compressionless on interrupted housing setups.
Compressionless took/is taking far longer than it should have to become the norm for mechanicals, and it is a little finicky and has to be installed right, but many bikes need it for the caliper to feel good regardless of what model it is.


Going for a start on a weekend like you are doing is a perfect idea.
Once you are comfortable with this (sounds like you're getting better already), perhaps the simplest and most time-effective way would be to try and use your bike to get to or from work.

You can start simple: ride to work one day a week, and if that makes you very tired, you can leave it there and return home by other means, riding your bike back the next day. I am a lazy person when it comes to exercise (I would never go to the gym) yet I have found that using my bike to commute effectively gives me 'free' exercise that does not take up any extra time in my day. As a bonus, it gives me something to look forward to in the mornings and evenings too!

No need to rush into things though. As you are doing, start with one day a week, and move from there when you feel ready.


Inspect the teeth of the chainring for damage. A single one might be damaged from hitting some obstacle. It may then produce a click when taking up the chain at the top and again as it drops the chain at the bottom of the turn.

The best way to do this would be to suspend the bike and have the chainrings at eye-level. Don't turn the bike upside down because it could change the conditions under which the clicking appears. Also try out whether the clicking appears when the crank is turned backwards.

Good luck and patience because sources of noises are notoriously hard to spot.


What type is my bike valve, and why can't I pump it up?

It's a "dunlop" valve. Also called "woods". I used to see this years ago in BMX bikes. For best results we'd use to have a schrader adapter (google: dunlop to schrader adapter) so we could inflate with schrader pumps.


Hydraulic disc brake - lever compatibility

An important reason why you can't randomly mix and match hydraulic brake parts is because different manufacturers use different hydraulic fluids. SRAM uses DOT 5.1 brake fluid. Shimano uses mineral oil. Campagnolo uses mineral oil. Using the wrong kind of fluid can damage the seals.


What is the deal with serrated/non-smooth rim sides on a bike wheel?

These are just machining marks from the tool that cut the braking surface. Rim manufacturers don't bother to get the braking surface completely smooth.

The tiny grooves don't negatively affect brake performance and will eventually wear away. You'll need to look for other causes of brake performance problems. Do you have new pads. New pads on a new rim make need 'breaking in', i.e. get a little wear before they achieve proper friction.


Rear derailleur cage hits largest cog on cassette

The inner plate seems to be on upside down. Not sure why but if it's second hand, maybe someone dismantled it to clean it the put it back the wrong way round.

If you need to swap it around you just need to undo the screws holding the jockey wheels in and flip it, then reinstall them. Its a bit tricky with the chain tension, but if you can do it without removing the chain, all the better.

Maybe drop the chain off of the chainring at least, to loosen some of the chain tension.

Make sure you get the chain routed correctly around the little tab on the inner plate, which is about halfway between the jockey wheels.

Also check the jockey wheels go in the right place and spin the right way; thanks to Carel in the comments, “If there's a difference between the top one and the bottom one there should be an inscription and an arrow with the sense of rotation.”


Can you have an Ultegra crank arm on the one side and a 105 crank arm on the other side

Yes, 105 and Ultegra components are largely compatible but it depends on the exact model numbers. Its best to check Shimano's compatibility charts.

I myself have a 105 crank on the left and an Ultegra on the right as the bump in my left Ultegra power meter crank won't clear my chainstay. They're both Hollow Tech II which means they're compatible.


In what ways is a dual pivot brake better than single-pivot?

The main point of a dual pivot is the mechanical advantage. Since the individual pivot for each side of the brake is optimized for a greater lever length, you end up with a greater pressure of the pads against the rim.

Also, since the pivots are cleverly positioned (in my opinion), you end up with a compact, light and strong overall structure.

The downside would be tire clearance, which is not big problem on road bikes. On mountain bikes, V-brakes provide very good mechanical advantage with a very good clearance, but with a less compact structure.


Can I replace a 26"/2,0 rim with a 26"/1.75 rim?

2.0 is the diameter of the tyre/tube in inches.  So a 1.75" tyre will be smaller and slimmer, and probably a little faster.

26" is the diameter of the whole rim, but check the tyre for its ISO number to be sure.  Its likely to be a ISO-559 size.

answer: yes that rim will probably fit fine.  You'll need to check and adjust rim brakes, or if its disc brakes then that needs to be right too.

Front wheels tend to survive better than back wheels.  If you're after a replacement wheel search out a local bike cooperative.  Our has dozens of spare front wheels and a lack of good rears.


Chain falls off upper pulley when backpedalling

Yes, chain falling off the pulley is expected. When you backpedal, the chain is moving from rear cog to pulley and you are moving the pulley away from the incoming chain. Don't do that. The pulley is by the way really worn, replacing it might improve things.
It should work, but you need to be very precise with the shifter.


Correct frame size, will 56 and 58cm work?

You have a few things to consider. First a Cannondale 56cm geometry is not identical to a Giant, Specialized or likely any other brand. Each brands designer has a specific goal in mind when they design a frame. So you can make a generalized statement that you may usually ride a 56cm it is not a hard and fast rule. One thing to consider is with the advent of compact frame designs the dimensions become virtual. This means that measuring the frame will yield a number other than 56cm. If the frame isn't marked for size you have to verify manufacturers dimensions to determine size or ask the owner how tall they are.
The most important thing to remember is not size but fit. The most critical is stand over height. If you can't comfortably straddle the frame it's too big. It also has to be comfortable, if you haven't ridden a drop bar bike before it will likely feel awkward for the first few miles. I would test ride a few 56s but don't overlook a 54 or two for test rides. Similar to buying a house or car try not to fall in love with the first one you ride.


Why does my drivtrain skip under hard torque?

Skipping like that is usually worn cassette, chain or chainring(or all 3).  Considering it's only doing it in the highest gears, my first guess would have been the cassette.  But since it's only a month old, it's much more likely to be the derailleur is mis-aligned just a little bit.  You say the derailleur is "ever so slightly bent", that little bit can make a big difference if it's out of alignment with the gears.  Also, as Criggie says in the comments, the cables "settle in" a little after about a month or 2 of riding, that's very common, and the reason most shops offer a free tuneup in the first year you own a new bike.  May be worth checking to see if the shop you got it from offers one.


Safety Bike Tail Light with Directional Signals

All this is very much depends on how good you are as a salesman. Very good salesman can sell sand in a desert and make good living.

I'm not sure what market you are talking about, but in UK you can get very different price range for the lights, top models priced at £144 ($227). And I have seen these lights used on the streets.

So $90 makes it costly for most of the people, but certainly you would find your customers who would want the set of features you are talking about.


Intersection detection doesn't notice me, what should I do?

In most states it's the law that if the signal is malfunctioning you can proceed through "with caution" against the signal.  Forester and others have argued that if a signal does not appropriately recognize the presence of a bike it's "malfunctioning" and you're on reasonably firm legal ground to invoke the "malfunctioning signal" provision.  (However, I've never heard of this being tested in court.)

Do note that the presence of a camera does not necessarily mean that the signal is video-controlled.  It may be that the cameras are there for general traffic monitoring, and the signal is still triggered by buried loop, radar detector, etc.  Also, often there are sensors installed for detecting oncoming emergency vehicles that look a little like a camera but are not.

If it is a buried loop you can usually tell by observing the cuts in the pavement where the loop was installed (though of course a buried loop may be subsequently converted to video control).  But with a buried loop the best place for the bike, to optimize detection, is more or less directly over one side of the loop, vs being in the middle of the loop.  (As a last resort, lay your bike down over one side of the loop.  I used to deal with one intersection where I could trigger the signal by just leaning the bike to about 45 degrees.)  Note that a steel bike will usually be more effective than an aluminum one, and a carbon fiber bike is unlikely to be detected at all.


How much faster will I be if I lose 10kg (from 100kg, all else equal)

According to BikeCalculator, assuming you drop 10 kg while everything else remains the same (power output, etc.), you would travel 0.3 km/hr faster over a 50 km ride, on the average. In other words, at 100 kg, assuming an average power output of 150 Watts, you'd average 27.54 km/hr over a 50km ride if you weighed 100 kg; doing the same ride at the same 150 Watt average output, you'd average 27.84 km/hr if you weighed 90 kg. That's an increase of very slightly over 1% in speed.

Having just gone from 100 kg to just under 90 kg over the past couple of months, however, I'd say that BikeCalculator understates the practical impact of losing that kind of weight. Since climbing, in particular, is basically all about the power to weight ratio, I have certainly noticed how climbing has gotten easier and how I can go faster up various climbs, and I intend to drop another 9-10 kg. For example, if you ride on a mix of terrain, both flat and climbing, you will gain more than 1% in average speed. Assuming the same average power as above, here is how average speed will increase with a 10 kg weight loss for climbs of different slope.

Best of luck dropping the weight and keeping it off.


Shimano Ultegra Bottom bracket replacement with Dura-Ace

Providing that is of the same type and size it will interchange. As an example hollow-tech II 10 speed BB30 English will interchange Dura-Ace, Ultegra, 105 will all fit. Ceramic bearings are sold as smoother hence less resistance, will you notice the difference? It is hard to say, but probable not except in your wallet.


There isn't a problem with it, though you may find your ride quality to go down a bit by moving to a smaller tire (but 23 and 25's don't really have much cushion to begin with so this won't matter too much). There is also a slight change in gearing due to the change in diameter of the tire. Generally though, I'd expect a bigger tire in the rear than in the front due to where you sit.

In general, you can mix tires so long as they go on the rims and clear the frame + brakes. Here is everything you want to know about tire sizing, including recommended rim widths for given tire widths.


Is it possible to use road-style brifters with an internal gear hub?

Based on the number of other people asking the same question around the internet, I suspect the answer is no.

This page contains the best wrap up I've found of available shifter options for Rohloff hubs.

Mittlemeyer may be bringing out some brifters that work with hydraulic brakes in September, but they've already delayed their earlier March release date.


Yes, I've used a variety of folding pedals on my Dahon and Brompton and they're all a bit flexy. I've had plastic ones snap in half on me (and yes, that can be very painful/dangerous). The best ones I've had were all-metal ones in which the axle and folding pedal were both metal. But even those aren't as strong as fixed pedals -- and none of the folding designs are designed for putting all your body weight on (by standing to pedal).  This is the MKS FD-7, perhaps the solidest of the folding pedal designs, but also quite heavy:

Instead, the best pedals sold for folding bikes are the removable axle pedals made by MKS and others. Rather than the pedal folding, the pedal axle disengages from the crank with a quick release. This removes the folding component  and so this type is stronger and more rigid. The other advantage is that you can also get clipless as well as regular pedals. But even with this design, the pedal will still remain the weakest link in your power chain. The removable axle thins where it enters the crank (which means that the bearings are also smaller) and that the pedal retention system while improved and generally bulletproof is not foolproof (they keep making better fools).

Here is their regular style Ezy pedal:

The ideal design would involve cranks that had a custom pedal quick release built into them  but that would mean you wouldn't be able to use standard pedals anymore and would be locked into that manufacturer, which makes me wonder why Shimano hasn't done this. :)


Is there any reason not to use a 9mm solid front axle hub in place of a QR hub?

The only potential caveat is many solid axle hubs come with toothed axle nuts that are good at chewing up dropout surfaces, particularly aluminum or carbon. On "nice" bikes it's always best to just use track nuts if possible to preserve the frame while still getting good clamping force, or washers at the least.


Type of cycle for losing weight and staying fit for a beginner

You want a geared bike -- not necessarily 50 speeds, but at least 3, preferably 15 or so.  If derailleur-style bikes scare you, there are geared hub bikes available (though they tend to be a bit more expensive).  (But, honestly, there's nothing to be afraid of with a modern derailleur-style bike, if properly maintained.)
If you're only going to be riding on roads and paved trails (which is most likely the case, at least first year or so), the type of bike makes little difference, so long as it fits you appropriately and is comfortable to handle.  (Though at your weight a "full suspension" bike is probably not a good idea, and, in general, even front suspension is not of much use on roads).
Mainly you should pick a bike that fits you well and is comfortable.  You need a 10-20 minute ride to really check this out, and any bike shop that won't let you do that (within reason) you should avoid.
Be wary of the handlebar.  Most bikes are delivered with the handlebar too low, and modern "threadless" front bearing setups require adapters to raise the handlebar to an appropriate height.  Make sure you get the handlebar height set appropriately before you leave the shop, and go back if it seems to need changing.
Be wary of the seat.  Many "comfort" bikes (which are worth considering) will come with an enormously wide seat, which may seem wise at the beginning but quickly chafes the inner thighs.  You don't want super-narrow, but likely not super-wide either.  (Of course the seat can be changed fairly easily.)  And, while purists sneer at gell-filled seats, they can be more comfortable for rides of intermediate length (over an hour, say), so long as they're not too "squishy".  Stay away from the pillow-like foam seats, however.

And do get a comfortable helmet (be wary of those with a large visor in front, they often obscure the vision), and whatever lock seems appropriate for your area/needs.  And be sure to get a light set if you ever ride at night -- nice LED light sets are now available quite cheaply.

As for shoes, usually a pair of athletic shoes is good for starters -- just avoid anything that's too wide due to lots of extra rubber on the sides of the soles.  Or an old pair of leather shoes will work for starters.  With your arch problem it's probably best to avoid anything with a too-thin, too-flexible sole, but hard-soled bike shoes are probably unnecessary, and could be counter-productive.  (I have polio-weakened ankles and arches and I biked for decades (including several multi-day tours) in plain old "tennis shoes".)

The shop where you buy the bike should give you a free tuneup after the first month or two.  Discuss this when you buy the bike.  If you buy a used bike from a private party most shops will do tuneups for a very nominal fee, often free, just to encourage your business.


Thats just a standard single-bolt seatpost clamp -- almost every seatpost on the market uses that clamping mechanism. Laprade was the original company who designed that type, but nobody uses that name with it.

In order to get the (clamp) nut/bar (cylinder) and bolt, you can check your local bike shop to see if they have something that fits in their spare parts bin or contact the manufacturer of the seatpost to get one or canibalize a donor seatpost.


What are the benefits of joining a team/club and when to join?

Keeping it general - if you're interested and keen on cycling for health or fitness, or you have a competitive streak, then joining a club is a good idea at any age, and at any skill level.

We can't speak for specifics of the clubs in your local region.

Most clubs quieten down in the winter/off months, more so at Northerly and Southerly latitudes.  Or they might shift focus to indoor riding if there is access to a velodrome facility.

The main benefits are

Access to experience and social interaction
Motivation to get out and ride
On a ride - a target or pace to maintain - gets you that little bit faster and fitter sooner.
Bulk purchasing power.  One club I belong to can supply consumable parts cheap, cos they keep a stock.  Any profits are turned back into the club too.

Drawbacks might include

Minimum attendance.  Some clubs have "members in name only" who don't contribute.  So its not totally odd to have a clause like "you must join in at least two rides a year."   Its not onerous.
Costs - Clubs have to charge subscriptions to cover their costs.  While it costs you nothing to ride your bike, the club will have
Socialising - Cycling is inherently an individual thing.  So it attracts those of us who might not enjoy team sport.  Being "forced" to socialise might be perceived as a downside.
Ridicule - I ride old bikes, and when I turn up at an event with my horizontal top-tube alloy bike from the 90s, there's always someone who looks down their nose at you for having not-the-latest kit.  Stuff'em!  Best thing to do then is put in an admirable time, better than last time.  Bonus points if you beat Mr Longnose!

If you don't want to join a club, that's okay, just ride your bike.  Tools like Strava can give you information on your progress and the competitive nature of segments helps.

Nothing is the same as keeping up on someone's wheel in real life, and feeling the boost of a draft.

Finally - clubs tend to run open days or public-access days where a ride or event allows non-members to participate.  Ask about locally and find out if such a thing is happening soon.  You can try it without committing.


Safe to mount rear rack for Grail 7.0 al 2020 ( no eyelets )?

It will really depend on how much load you plan on carrying, the type of roads you would be traveling and somewhat your riding style.

I would not recommend the use of that particular rack on a road bike unless it is for little or minimal load on really even roads. Particularly for touring, as damage to the frame would be a trip stopper.

I have used racks that only clip to the seatpost, and also racks with supports for the proper eyelets in the frame.

Seatpost only rear racks are fine for a lunchbox, a few pieces of clothing. Something around 15 pounds (6 Kg.). You can carry a bit more if being really careful while riding over any obstacles, curbs, potholes, etc.

Moderate loads on this type of racks will cause fatigue failures sooner or later, except maybe on the highest quality ones. On low or mid level ones, it's just matter of time. In my case I've had failures on the main rack beam, near the weld to the clamp.

In the case of racks that mount to eyelets near the dropouts, they are the sturdier but the force of impact while hitting a pothole, jumping of sidewalks, etc is pretty direct. In My case I had a cheap rack and the support rods where made from soft aluminum and bent rather quickly. I had to re-make them with rebar. (Mild steel rod about 1/4-inch diameter). With this setup I was able to carry loads heavy enough to lift the front wheel if I unmount the bike without pressing down on the handlebars. I used this bike to commute, for grocery shoping and for delivery service (With a medium sized plastic crate tied to the rack).

The point of this anecdote is to show that the vertical force for a proper rack is rather high. On a bump the supports "see" many times the static load applied to the rack. In the case of a frame with eyelets designed to install a rack, the eyelets are placed on strategic points to transmit the load to adequate points on the frame. For example, near the dropouts (The force is transmitted almost directly to the axle, without applying significative bending force to seatstays or chainstays.)

All of this was done with a mountain bike aluminum frame. They are sturdy enough to cope with that kind of abuse (up to a limit), however, road bikes tend to have minimal thickness wall tubing to reduce weight. They optimize the frames for just the strictly necessary forces, so extreme care must be taken when mounting this kind of accessories.

The rack you have shown uses not vertical but tilted supports, if they are not long enough for the wheel size of the bike, those supports won't be able to reach near the dropouts, and may end upd clamped near the middle of the seatstays, perpendicularly, right where they are most vulnerable. (Imagine trying to break a stick, where do you apply force and in what directions?)

Another concern is that the clamps on the rack may not be the exact shape of the seatstays tubbing, thus will apply a crushing force on them. You risk deforming them and once that happens, they area permanently weakened.


I don't know what kind of tires you're running, but 65PSI is a really low maximum pressure for a 700x32 tire. I wouldn't exceed it if I were you. I'd probably throw them out and get a pair of tires that are a little more confidence inspiring.
Tire pressure is more of an art than a science (even moreso with mountain bike tires), and much of it is going to come down to preference. The skinnier the tire, the higher the pressure. The bigger the rider, the higher the pressure. To a lesser extent, the higher the TPI (threads per inch), the higher the pressure. There is a sweet spot between the min and max pressures, and it depends on the mentioned factors and more, and each rider just has to feel it out for themselves. That said, Michelin has a chart that can provide a decent starting point for road tires and you can go up or down from there as you please. Keep in mind they've designed this around their own tires, and ultimately other reputable sources probably have other opinions on the matter.
In Michelin's words:

 Just as with your car tires, proper inflation pressure is very important to how your bicycle tires perform and last. And as with car tires, the most important variable that affects what the proper pressure should be is the load your tires are asked to carry.Thanks to more than a century of tire technology research, Michelin engineers have found that there's a certain amount of deflection in the tire profile that's optimal for balancing grip, efficiency, comfort and durability. That deflection is based on the tire's construction and the weight of the rider. Obviously, your style of riding can have an effect too, but the chart below should give you a reasonable guide of where to start when experimenting to find the proper tire pressure for you.

There are a few related interesting tidbits at Michelin's site.


What kind of tires I can use with tubeless rims?

The rims spec'd with a lot of new Trek bikes (including yours) are "Tubeless ready". This means that you can run tubeless, but you can also run regular old tires with tubes (i.e. clinchers).

The primary advantage of running a tubeless tire (which will be marked as tubeless) is that you can run a lower pressure without getting pinch flats, which is advantageous in the winter. However, you have to faff about with sealant (and the right valves, rim strips) to get this done [along with obviously buying the tubeless tire]. Note that if the seal fails, you should be carrying an inner tube (regardless of running a regular or tubeless tire) so you can throw it into the tire to get you home.

If you run a regular tire (i.e. a clincher -- tubular tires are a specialty item for track racers, so don't get the terms confused), you should an inner tube in and install as normal. If you're running the tires that shipped with the 7.4 FX originally, you have a regular tire (which has a tube), so you just find another tire which is about the same size (probably something around 700x32), pop off the old one and pop on a new one. Regular tires are also a bit cheaper.

There are people who run regular tires as tubeless (at their own risk - some tires take this, others don't). You can try this at your own risk, but for winter, I'd probably just go for a regular clincher tire with inner tube. The tires you can fit onto something like a 7.4 FX will be narrow enough that the lower pressure advantage of a tubeless tire will not really help you. Maybe a regular studded tire depending on where you are and what your road conditions are like.


What's the rubber tube in my puncture repair kit for?

It is the Dunlop valve, it was used a lot in Holland, UK, etc.
You can see it in action here:

But currently it is replace by the Blitz:


Unless you are particularly heavy, I would not worry about size - not that much difference in load carrying between a 2.1 and 2.4 that it will cause a blowout. Blowouts are caused by a tire failure of some description (bead failure, not seated on rim properly or cut to tire are the most common causes). You say "old tire and tube" - how old and what condition?

If your choice is ride on the 2.1 or not ride - I know what I would do.


Upgrading SLX brakes, do I also need SLX rotors?

(Proviso - I assume your existing rotors are in good condition - if not the upgrade is a replacement of a worn component which needs doing anyway.)

It will be fine to use existing rotors.  Rotors come in all shapes and sizes and prices, so it can get confusing, but within the same size, the difference is more about balancing cost, weight and durability, the ability to shed mud and the ability to handle heat. Throw into this mix marketing and sales, and most of the information you will find is driven towards getting you to spend money you do not need to spend.

There would be advantages in upgrading, my guess is they would be very small and probably imperceptible once riding. You gave no indication how much cash you have burning a hole in your pocket, so we cannot really give you a "Is it worth it? Yes/No" answer.


Swytch eBike conversion wheel axle diameter

Presumably you have a bike designed for quick-release wheels that have a 9mm diameter axle.

The Swytch eBike conversion wheel seems to use 10mm solid threaded axles that are secured to the fork with nuts - which makes sense as this provides higher clamping force required to handle the motor torque. (FWIW, this fact seems to be absent from the Swytch website, and it means that their product is not compatible with any bike.)

If your fork dropouts have sufficient material, you may be able to enlarge the dropout width with a file, but beware that you will not be able to use the 9mm axle wheel. It would be dangerous to do so.

You could also find a cheap fork designed for threaded axles. You would need to match your current fork's geometry (headtube to axle distance, rake). As threaded axle hubs are used on cheap bikes you will not find a replacement part available for sale as a separate component. You'll want to get one from a old used bike. A good source for things like this are bike cooperatives or  bike stores that specialize in refurbishing old bikes. They often have piles of bikes that are not worth refurbishing or frames that have had parts stripped from them.


For a studded tire that is available in both 29" and 27.5" which will perform better in snow/ice all else being equal?

Wheel size probably doesn't matter that much, the one that would probably perform better is the wider one with more aggressive tread or the one with studs.

However, once you get to a certain width (I'd say above 3.0) then tires can start to more easily wash out sideways on wet snow, which I get on my fat bike regularly, but not so much on my 29er or 27.5+ bike.

You're right though, about having more options for 29er tires with studs.


Road shifter to Mountain Bike derailleur compatibility (Example: SRAM x7)

Most SRAM 10 speed road levers will work with a 10 speed x5 or x7 mech.
Its to do with cable pull ratios - SRAM are using a 1:1 ratio they call .
'Exact Actuation'

Follow link for a list of compatible products


Do I have to stop pedaling when shifting up the front chainring?

Use the Clutch!

This is what I always tell people when I'm teaching them how to shift gears properly. Chain-rings and Cogs are machined with *pickup points" that assist transferring the chain from one ring to the other, they only work while you're turning the cranks. So I tell people to let all the power off of their pedals, but keep the cranks turning and don't step back into the pedals with any force until the chain has fully shifted.


Upgrade old Gary Fisher MTB drive train to 10 speed

Yes. The same Hyperglide freehub body spec is used for 8 through 11 speed drivetrains on mountain bikes.


How similar are saddles made by the same company?

The only thing that you might be able to bank on is the width of the saddle.  I know specialized in particular has different widths for the same model of saddle based on where you sit bones are.

Other than that, you will really need to try each saddle to know how it's going to feel.  I have the Toupe on my road bike and it's fine for a road bike but I wouldn't want it on my MTB.  It doesn't have as much padding as the specialized MTB saddles.

Short Answer: You have to take each model into consideration individually.


Can I even put in a solid axle in this wheel/hub?

Probably not. The axles of QR hubs are generally not designed to be removed and replaced with a through-axle. Some hubs are designed for both retention systems and can be converted. This does not look like one of them. I've never seen a rim brake hub with a through axle.


Clicking noise coming from cog on fixed gear

Is it the same link every time? There could be a tight/sticky link in the chain from when it was installed. I'm not sure why that would have come up after removing/replacing the wheel, but it's worth checking.

Mark or otherwise make note the problem link
Take the wheel off or push it in the dropout to put slack in the
chain
See if that link is difficult to bend
If it is difficult to bend, then set your thumbs on it, push it side-to-side, quite
    firmly but not with all your might, until it becomes less sticky


Got two bikes, one of them is more exhausting to ride, what can it be?

I can see 3 possible causes for the bike being more exhausting than it "should" be:

1: Lack of (or incorrect) previous maintenance.

Particularly you mention you bought it from a "clueless" person. It is likely that such person didn't knew when to take the bike to maintenance and was not very careful on how or where to keep it while not in use.

Some bikes are factory packed with such types of grease and lubricants that in short time can gum-up, and cause a seizure-like effect instead of reducing friction. This happens particularly in low end bikes, where cheap grease is used, so it lets evaporate part of the oils leaving only a paste-like residue. This may not be evident when moving parts by hand, but a tiny amount of resistance in every axle adds up when riding. When this happens in the pedals and bottom bracket, the effect on the rider is very noticeable, still the bike is felt to roll freely, but heavy to pedal.

The fix for this is a complete disassembly of the hubs, bottom bracket and pedals, cleaning completely the internals and reassembly with good, fresh grease. Of course this covers correct re-adjusting of hub cones, bottom bracket cones and pedal axle, etc. which may be currently over-tightened.

The chain may also be suffering from this. You can change the chain or deep clean and re-lube it.

2: Low end components too low

Some bikes are produced with low quality components, which are not formed properly and are made out of incorrect materials. In particular, chainrings, bottom bracket and cogs. Low end ones are made of low grade steel which is heavy and kind of soft. The heavy part has an obvious effect.

The softness of the steel is a major problem. When bearing cups or cones are made of soft steel, the balls "sink" into them because the steel flexes a bit, creating resistance. Think of it like rolling a pool ball on a bed, versus rolling it on a proper table (which would be a bearing on proper steel). This effect is very subtle and can not be noticed when moving parts by hand, but when real load is applied (i.e. actually pedalling) it is greatly increased. A similar thing happens between mild steel chainrings and the chain.

Also, poor quality components are often poorly machined, which means they do not have the right shape, just a very similar one.

This is the main difference among low end components and reputable ones: the quality of materials and machining used.

The only remedy for this is to upgrade components. It is not necessary to break the bank, there are a lot of good, affordable components made by reputable makers, which can be a good option. For example, almost any Shimano component from the basic line will perform better than a generic brand-less component from a Walmart bike.

If it was my bike and I needed to make it easier to ride, I would upgrade bottom bracket, crankset and pedals first followed by cog set and finally hubs. (And I would do it progressively, not all at once and only if the bike frame is worth the effort).

3: Geometry and fitting Issues
A bike with different geometry can be more tiring to use. Besides this, a poorly fit bike makes the rider-bike system less efficient. The bike may have good geometry but be severely far from a proper fir for the rider, it may even be the incorrect size.

Do a search for "bike fit" to check some critical points like saddle height, and effective top tube length, among others. If you can't adjust the bike to get it close to the recomended positions the bike may be too small/to large for the rider.

Other factors
I have left this apart because it is kind of obvious but:

Check if tires are properly inflated and in good shape. Tires at lower than recommended pressure generate more rolling resistance. A good tire can safely go up to the max pressure labelled on its side. If it doesn't seem to be able to hold up, then it may be too old and must be changed.

Check for rubbing brakes, or tire rubbing on frame.


Since a single pair of V brakes is not much more than 2-3x the price of decent set of pads, why won't you try a different pair of V brakes? It's not hard to install, only bit more work as changing the pads. Also having some play on the brake arms is a cause for concern -- there shouldn't be any play in decent brakes apart from sidewards play against the spring due to the pad gap.
In one of my bikes, the front brake squealed like hell. It's not V brake but cantilever. I assume some combination of cantilever brake arms, rims, fork and pads caused the squeal. Changing the Kool Stop salmon pads to Shimano S70C pads fixed the squeal for me.


How do I know if the tandem bicycle I've inherited is worth repairing? It has a serial # 459310 on it, no other identifiers

The issues you've identified aren't terribly serious--however if they aren't a comprehensive listing of the issues (such as bad bearings, etc) then they may be understating the amount of work required.

The question of whether the make and model is "worth" repairing is largely up to you to decide.  Being an unknown bike you should evaluate it on the value it has for you, rather than a broader market value.

The specific issues you've cited aren't terribly costly to resolve.  You can purchase replacement tires, handlebars, and saddles from any good used parts shop for a fairly low price.  A new chain is a small investment, and is a regular component to replace.

Overall though I presume your question is omitting some details.  Photos and a more comprehensive listing of known issues will help better evaluate the potential to return the bike to a functional state.


Is a 7 speed chainring compatible with an 8, 9 or 10 speed cassette and chain?

7 speed systems use slightly wider chains, and the teeth on the chainring are slightly wider too. You might run into an issue with a ten speed chain not fitting over the teeth, or at least not fitting well.


Can I use an expanding plug rather than a star fangled nut in a steel steerer?

Can I use an expanding plug instead of the star fangled nut?
Yes you can.

I thought I would expand this answer to say that:
-certain expanders add an extra 1-2mm to the top of the steerer tube, meaning you may need an extra spacer depending how you cut
-Quality steel steerers are thin walled so you may need to shim your expander with e.g. some inner tube if you need a bit more bite. Apart from eliminating a sharp edge and making things look neat, they only hold the bearing preload and don't hold the assembly together. You already know this but I've seen enough bikes with Mega Torque on the preload bolt in the last 3 months to know that there are a significant number of people who don't know how this system works.


Headset/fork adaptor from semi-integrated to integrated?

You've used whatever crown race was installed previously on the fork. It appears to be for a looseball type headset. Crown races from such headsets are matched to the other parts of the headset and, unless designed otherwise like a few manufacturers do within their lineups, have no interchangeability with other headsets, and certainly not with any type of cartridge bearing headset. Cartridge headsets take flat-faced crown races to interface with a cartridge bearing. The kind you have has a curved face to interface with a ball bearing.

In some cases one might be able to find an individually obtainable crown race to match an existing headset. There is high interchangeability between many integrated and internal cartridge headsets and crown races, but it's not a given. Bearing face angle and seal interface are both factors that can come up sometimes.

Look into buying a new crown race for your existing headset, or swap it from the old fork if you've got it. If those avenues are not options, buy a complete new headset. The removal and installation tools for all of this can sometimes be improvised and sometimes not, but there are many questions here about this.


Is cyclocross tire (CX) taller than normal road bike's?

BB height is a measurement that depends on too many ill defined parameters to be useful.
A rough approximation for three height of a tyre is to take its nominal width. That leaves us with a discrepancy of about 8 mm. Spezialized seem to have used either a height from the tyre manufacturers data sheet or actually measured themselves.
Tyres deviate from a perfect toroidal shape. For example, a fully inflated tyre on a narrow rim might be much taller. Rim and casing will determine the actual cross section.
There is also a layer of thick rubber to roll on and, in the case of the CX tyre knobs.
Lastly, for a real measurement one has to consider tyre drop* of the tyres. For road riding up to 15% is typical. CX tubular tyres might be depressed by 50% however.
Finally, Spezialized's road section might use different conveniens l conventions than their CC section or MTB section.
Overall there is so much guesswork in interpreting that value that you might only find out that BB height means by asking Spezialized themselves.

Tyre drop is a measure of the reduction of a tyre's extension in radial direction under a radial force oriented towards the hub.


If the length of the bike is makes it legal, hitch rack with the bike sticking out would be the cheapest and easiest - You would be no wider than trailers and trucks, but care would be need to remember that. Get a rack fabricated that holds the bike vertically off the hitch, Strop the top roof the rack back to the roof bars. For ideas have a look at here and talk to an engineering shop.

Have a look for ideas to carry tandems - Here is one idea that would work.


Should I not use a trail because of poor conditions?

It's common etiquette, at least everywhere I've been, to stay away from wet and muddy trails (unless they're supposed to be or always are a mudfest). Riding on a muddy trail makes ruts which make the trail conditions worse for everyone once the mud dries and the ground hardens.

In addition to ruts, if the trail is muddy and you slide out a front wheel going around a turn, for example, your wheel can scrape several inches of trail off. This can cause erosion problems later on.

However, as alluded to earlier, if the trail is a known mudbog and stays muddy year-round, one more rut probably won't hurt anything.

Another common counterexample is when the trail is melting in the afternoons but can be ridden early in the day when the ground is frozen. If you're crazy enough to be out riding then, more power to you.

But generally speaking, it is in good taste to stay off melting, muddy trails. Any time your presence can alter the trail physically (ruts, slide-offs, feature damage), everyone else who shares the trail with you will be glad you stayed off.


How much to eat and drink during a 50km ride?

50km isn't that enormous of a distance - and especially for someone who does 18km twice a day.  It sounds like your current pace would have you completing that in about three hours.  I'd bring a snack or two if you're worried about being peckish, but unless you're going all-out for a personal record or you skip breakfast you should have no issues.  Just keep turning the pedals, make sure you drink some water, and feel free to take a 5-minute stretch and snack break if you're feeling tired.


Will my chain line be affected if I use a BB386EVO crankset on a standard cartridge BSA frame?

BSA or 'English' or ISO standard refers to the the thread in the bottom bracket shell (1.37in x 24 TPI). Both cartridge and external bearings fit in this these shell threads. There are several standards shell widths: 68mm for road bikes, 73mm or 83mm for mountain bikes.

There is no such thing as a bottom bracket chainline offset chart. Each bottom bracket standard has a specified external bearing width and internal bearing diameter. Cranks designed for a BB standard have the correct axle diameter and length for the bearings. The crank itself positions the chainrings for a specified chainline, not the bottom bracket.

You can read about BB standards here: https://www.bikeradar.com/advice/buyers-guides/the-complete-guide-to-bottom-bracket-standards/

The external bearing bottom bracket you reference will fit in a 68mm shell (you can see this in the specs on the web page) and provide the proper external bearing width of 86.5mm for BB385EVO. You need to check that your BB shell is the right width. You then need to check the specs of the crank to make sure it give you the proper chainline for the bike you are building up.

If you are building a road bike your BB shell will almost certainly will be 68mm, and a standard BB386EVO road crank will give proper chainline.


I have been experimenting with tire pressure and stem length trying to improve front tire grip and steering on my trail bike which is often slipping in corners.

I cannot see how tire pressure can affect weight distribution in any measurable manner. A very minor effect on the static weight distribution may perhaps be observed on a fat bike, where a severe underinflation of one tire actually changes bike's geometry (by visibly raising or lowering one of its ends). Adjusting tires' pressure may help with getting a better traction, but the involved physics do not have much with the weight distribution to do.
Changing stem length is obviously a different story, as a longer stem may force the rider to shift their center of mass forward.

I'm guessing I might get closer to 45/55 on a road frame. But I am nowhere near that on my mountain bikes

I do not see how a "recommended" weight distribution, if there was such a thing at all, provided for a road bike can be applied as a measure of anything for a mountain bike. These types of bicycles have different dynamics and areas of use.
If we track trends in changes of static weight distribution for mountain bikes over the last three decades, I am sure that we will see a trend of weight shifting from front to rear. MTBs of 90's were inspired by road frames, and modern MTB's tend to have rather short chainstays.
What really makes these numbers irrelevant is the fact is that under braking/acceleration the weight distribution between front/rear wheels is nowhere close to the static values.


What is the purpose of a braze-on on the underside of seat stay?

I'm not positive, but I believe those are for a frame-mounted wheel lock. These are locks that you mount to the frame in roughly that location that immobilize the rear wheel when locked. Typically they mount via the brake braze-ons or their own straps, but that location looks about right for a direct mount

An example of a fitted lock can be seen in this image:

This type of lock is convenient, but not especially secure, since a thief can always just pick up the bike and carry it off. Some do include a way to plug in a cable or chain in order to lock the bike up to something else, but those aren't especially secure, either.


Alternatives for front shifting for small hands

You could run a bar end or downtube shifter in friction mode to accommodate a triple.

You can run a sram shifter with shimano FD, but they only work for double as you suspected. For the most part, FDs are dumb, it's mostly just the shifter that has all the smarts.


The cap and bolts are readily available, if you want no need to stick to a boring round black thing - they come in all sorts of weird and wonderful shapes, colours and functions. You can get them with bottle openers and clocks.

The cap and bolt is only needed to set the preload on the bearings when installing the stem. Once the stem bolts are done up, the cap and bolt does nothing (although for safety, I would not ride a bike with no cap). Therefore if you do not undo the stem bolts, all you need to do is put on the new cap and do the  bolt up. The bolt only needs to be tight enough it does not come undone - 5nm should be enough (that is not much). You do not want to be a gorilla on the end of the spanner.

If you have undone the stem bolts, you need to loosen the stem, do up the cap bolt till the play is removed from the head set, line up the handle bars and tighten the stem bolts (typically 5-7nm, much less than most people think).


I have an old giant 9 speed, which I want to convert to an 11 speed, simpy to use on a smart trainer

You can convert it to 11 speed, but it involves changing a bunch of parts.

Obviously, an 11-speed cassette is required. For a road bike: you should check if your freehub body has a spacer, if it does then the hub can accept any Shimano/SRAM 11 speed cassette. If there's no spacer, you can get a Shimano CS-HG800 (works with narrow freehub bodies). If freehub is Campy-spec, then any Campy 11-speed cassette will fit. Another option is to source a wider, aftermarket freehub body if such an option is available. For MTB: get any 11-speed cassette compatible with your freehub (which is most likely a regular Shimano HG).
You will need 11-speed shifter(s), compatible with your new RD. A cheaper solution might be to get a friction shifter or only a rear shifter and leave the old front shifter as is. You did not say what RD you already have, but I hope it's a not an MTB-specific one, otherwise you'd have "fun" looking for a compatible shifter option (there are some).
Any 11 speed chain.
Make sure your new RD can clear the biggest cog on the new cassette. Usually, this info can be found in product manual.
Make sure the RD can handle the chain growth capacity. I'm not sure road 11 speed system work with a triple up front, you did not specify what the current groupset is.

As you can see, there's a lot of variables involved, a list of current parts would simplify the answer a great deal.


What makes a great kids city bike? (and where can I find or how can I build one?)

So, if your kids are like most, they are going to be hard on bikes. They will jump off curbs, do wheelies, and likely toss them to the ground when they dismount. I recommend something that will take a bit of abuse. A bmx will take a beating but it is an awful commuter bike. Beach cruisers are not much better - and they won't take the abuse.

I recommend a hard tail mountain bike for most kids. A hard tail is one with only suspension in the front. You will want to make a single change to it, put on some slick road tires. A slick tire mountain bike can be fast, I recently had one fly by me on a 100-mile ride (and I am pretty fast)

A hard tail is a great choice because it is cheaper, lighter, and easier to maintain than one with suspension in the back as well. You can often find them for a good price used. They will accept all of the accessories that you mention.

Whatever you do, don't buy one from a department store. A used quality bike will be much better than a brand new one from a box store any day of the week.

You will need help finding a good one, quality varies a lot. Look for brands like specialized, giant, trek, Santa Cruz, though there are many others. Stop by your local bike shop and ask if they have one used, or bring in some ads from Craig's list. If you start by saying "I would like to get a bike and have you service it", they will be apt to help you more.

Also, pinkbike.com is a good source for used bikes and parts. You can filter for bike types, location, price, etc. Expect to pay at least $250 for a used one, and that is bottom end. Process will go up from there.

I hope that helps.

Cheers


Shimano sora 9 Speed rear derailleur capacity

There are two 9 speed Sora groups, 3400 (older, with thumb button shifters for upshifts) and 3500 (current, with a paddle for upshifts).

The Shimano RD-3400 SS has capacity 31t and GS has capacity 37t, both with 11t smallest sprocket, 27t largest sprocket (and 16t chainring and 22t chainring difference respectively).

The Shimano RD-3500 has SS with capacity 37t (front difference <=16) and GS with capacity 41t (front difference <=20). The sprocket ranges have to be (11-14)t to (25-32)t for both.

Wiggle doesn't list which one they're selling, but it looks like they have part of a description from 3400 and part from 3500.

In any case, if you were to buy one, you should get the RD-3500 SS or GS. However, in reality, you can likely use any of them (the specs the manufacturers list can be violated by a tooth or two, normally), at your own risk, of course.


Pain in right leg, related to asymmetric leg position?

Before you start looking at bike setup/fit and/or different bike parts I would get your flexibility assessed. With one knee deflecting nearly a 1/2 foot more than the other, this suggests either underlying flexibility issues or functional issues. A bike fit can help to some degree to mitigate the issue, but a good fitter will also tell you that modifying bike fit is no substitute for fixing any underlying flexibility/functional issues.

Knees do not take kindly to off angle loads, in fact neither do most the joints in our legs and hips.  Often flexibility issues can cause us to modify our pedal stroke to compensate, including knee deflection, which can lead to repetitive stress injuries.

Do you sit down a lot for work?  This combined with cycling can really do a number of hip joint flexibility, which can have far reaching functional ramifications outside of just cycling depending on how your body compensates for any lack of flexibility.

Do you have a regular stretching routine?  If so, good.  If not you might need to consider this (especially hip and hamstring flexibility) as part of your regular routine.

Do you release muscle adhesion (and potentially muscle shortening) in your legs? - Sometimes referred to as muscle knots, these can also affect range of motion and therefore realized flexibility. Self-message (e.g., leg rollers) can be used to release these.  IMS treatment also works well.

  Anecdote:  Muscle adhesion and shortening in my upper quad were affecting my range of motion through the upper portion of the pedal stroke causing knee defections inwards (my compensation behaviour) which resulted in IT band issues (outer knee and outer hip discomfort).

Above all I would consider getting an assessment from a physiotherapist who can identify functional mobility issues. This is the best place to start, especially considering one knee is deflecting out nearly 1/2 foot more than your other. When one knee tracking is this far off, it is only a matter of time before repetitive stress injuries arise. Bike fit changes can compensate, but the issue will likely re-emerge especially if there are further change to flexibility and functioning. Once issues are identified, you will likely be given strengthening and stretching routines to help address the issue. It is worth sticking to them for long term health.


There are so many factors involved that can lead to back pain that I would be suspicious of anyone providing the answer.

Some factors that can affect

Your current bike fit.

Body angle: is your current fit very aggressive or more relaxed?
Is you seat set back appropriate or too far back?
Is your saddle height correct for your level of flexibility?

Your Technique

How do you position yourself on your bike  when climbing  (e.g., do you use the tops of the bars or do you get in the drops)?
Do you spin or do you mash gears

Your current bike setup

What gearing do you currently have
Is this gearing sufficiently low enough for climbs

Other personal factors

Have you injured your back before
What is your hamstring flexibility
What is your mid and lower back flexibility
What is your hip flexors flexibility
The list goes on

Summary

After addressing all of these issues I would then start looking at factors such as core strength, functional weaknesses and associated exercises.

In short, narrowing down the cause of back pain is often can be difficult.  I would suggest finding a someone who specializes in both physio and bike fitting. They exist and will likely be your best bet at tracking down the cause and finding a solution.


My general rule of thumb is 10-15% lower than the posted maximum for normal road riding. Higher if you're carrying a load or are a larger rider, lower if you're a lighter rider. There's an article in Bicycle Quarterly that's a pretty good guide on tire pressure for road riding depending on weight and width of tire.

http://www.vintagebicyclepress.com/images/TireDrop.pdf


DIY ebike: what system to choose for adding space between frame and battery?

I think a problem with option 3 is that the screw’s tightening torque is “pulling” the rivnut out of the frame (in addition to any force acting on the battery). With option 2 the frame only receives the actual forces acting on the battery.
Sideways stability should come from your mounts being several centimeters apart, not from using wide washers/spacers.
In all of this I’d make sure to use threadlocker and sufficient tightening torque (like >4Nm) to make sure nothing comes loose and starts weakening over time.
Oh, and one idea: Instead of rivnuts, why not drill through the whole frame and use very long bolts and a bracing plate (or wide washers) on the top and bottom? Or even just clamp plates around the frame without any drilling and mount the battery to the plates.


Have you looked at the 12 speed group from Sunrace? https://singletrackworld.com/2018/04/found-sunrace-has-a-new-12-speed-mz90-11-50t-cassette/

Or just released from SRAM is the new 12 speed NX group that uses at standard freehub:
https://www.sram.com/sram/mountain/family/nx-eagle


Would Putting BMX Bike Brakes on my Road Bike be Ok?

Not easily.

V-brake levers pull twice as much cable as a calliper brake levers, so you'll not be able to swap them without swapping the levers too, and these are often attached to the shifters, so you'd end up swapping an awful lot of parts.

Additionally V-brakes are mounted to a pair of bosses on the seat stays & fork legs whilst calliper brakes are mounted to a hole in either the bridge of the seat stays or fork crown, you might have these holes on your frame, but it does leave the ugly V-brake mounts unused. Although BMX brakes seem to use the 2 boss mount like V-brakes, I'm not an expert in BMX, that's more my brothers area.

As an aside, what makes you think the BMX stuff will be better? BMX stuff is usually designed to be robust rather than the absolute best.

Your V-brakes are almost certainly good enough.


At the beginning of this video:

http://vimeo.com/41982043

it looks like this bike messenger has an extra strap for his bag that comes up under his left arm to stabilize his load.  Looks pretty neat, like it can be easily unsnapped to get the normal messenger bag access, and possibly be DIY-able.


Can a thicker chain cause it to slide/jump under pressure?

No. Most common chains are 1\8 (single speeds) and 2/32 for your average multispeed chain. Of course 8 and 9 speed chains can be thinner.  It may be your sprocket. You didn't state how many miles is on the bike in it's current setup. If the rear sprocket is worn, chain will skip.

Also if the chain alignment is too far off, it will skip or come off. A single speed set up puts more load on a chain without a derailleur to dampen some of it and hold it in place.

A bent chainring on a crank can possibly throw it off or cause similar problems.

If you just shortened your chain and pieced it back together by driving the pin back between the links versus using a or the masterlink, that point can be too tight and inflexable depending on how far the pin was pushed in. It can be microns of a difference and that link won't flex.


It's probably some kind of unfixable (given the lack of replacement parts) problem with the pistons. If you want you can take apart the caliper to confirm, using a blower attachment on an air compressor to pop the pistons out and inspect them. But what it comes down to is if your no-service-parts-availability caliper is leaking oil repeatedly, there's not a lot you can do but replace it. Luckily a new BR-M785 complete with finned pads is under $50US.


Can I drop-in a compact crank set with my current 105 groupset

You are right to say that the compact crankset will give you smaller gears to help you get over hills.

You can do a straight swap of the crankset, everything else will be compatible, although will need readjustment.

If you currently have a 5600 crankset, then you are absolutely safe to swap for another 5600 (compact) crankset. Now, the compatibility between different Shimano ranges is governed by the number of sprockets on the cassette, and the good news for you is that both 5600 and 5700 are 10-speed. So, basically, 5600 or 5700 cranksets will fit you perfectly (as would any other Shimano 10-speed road crankset).

5800 is an 11-speed system, you could probably get away with using this crankset (since the differences are small), but it will not fit as perfectly as 5600/5700.

So, looking at Shimanio's site, the part you need is either the FC-5750, or the FC-5650. The "50" appears to denote compact.

Lastly, do you know what length your cranks are? It might be worth measuring this just so that you get the same length with the new crankset. (You'll see on the Shimano site that things are available in four different lengths, the differences between each are small but they will affect your fit.) Here's an example of what you're measuring:


Can a new chain significantly improve the riding experience? If yes - what else can?

The one substitution that will probably give you the most bang for your buck is better tires. High-quality tires roll with much less rolling resistance, have better grip, weigh less, and roll over small imperfections more easily. And if you're riding on tires with knobby treads, but only riding on the road, tires with minimal/no tread will ride much faster and smoother.

Keeping your drivetrain clean and properly lubed will also make a noticeable difference.

Making sure your bike fits you will make a big difference, and you may want to get new handlebar/stem/saddle to achieve a good fit.


Am I going to get injured mountain biking if I don't have rear suspension?

First off, when riding over rough terrain you should be hovering above your saddle, not sitting on the saddle.  This holds whether riding a hard tail (no rear suspension) or riding a full suspension bike. If you are sitting you have less ability to move your weight around, and therefore less control of the bike. When sitting it is easy for a large bump to throw you off balance making you crash or swerve into a crash.

When the trail is really steep and rough not only you should be off the saddle, but you should also be putting your weight behind the saddle.  Example below pictured below.  These riders are on downhill/freeride bikes (tons of suspension travel, 6-8 inches) and they are not sitting on the saddle.

So what advantages does rear suspension provide?

When the terrain isn't too rough (smoother than the above picture) it can allow you to sit down and pedal in more circumstances than on a hard tail, which can especially help when climbing (assuming an efficient pedalling suspension design)
Although your legs are the ultimate shock absorber (when hovering above the saddle) rear suspension supplements this natural suspension.  This can be critical when:

absorbing hits from big obstacles
landing off drops and jumps
absorbing a g-out
absorbing a series of fast rapid bumps as your legs may not react fast enough.
rescuing you from stupid mistakes or a bad line.

Depending on the suspension design, the rear suspension can also improve braking as the rear tire is in better contact with the ground.  (Although in some suspension designs braking can negatively affect rear suspension performance and therefore traction.)

What about hard tail?

To compensate for lack of rear suspension travel you need to use your legs more.  You should be riding above the saddle more often than with a full suspension bike.  For example, if you are pedalling over roots or rocks you need to learn to pedal while hovering over the saddle.  This lets the bike move over the terrain, maintaining traction and forward momentum.

So what are the advantages of a hard tail?

Hard tails are typically lighter bikes (less parts), and can be more efficient to pedal especially on long climbs. As such they still have a following among Cross Country (XC) mountain bike racers on smother courses.  That said, I have personally found the efficiency gains can be easily lost in rougher terrain (e.g., Squamish BC).  Hard tails are also cheaper to manufacture (the frame doesn't have any moving parts) so you can get a better equipped bike for your dollar.  This makes hard tails good first bike.

Hard Tail or Full Suspension

Whether or you choose hard tail or full suspension really depends on your experience, budget, riding style and roughness of your terrain.

What constitutes rough differs from area to area.

I personally live and ride on the North Shore of Vancouver Canada which has some incredibly rough and steep trails (pictured above).  My XC bike has 5 inches of travel front and rear and I use all of it on XC rides.  It does not have enough travel for some of the more advanced downhill trails in our area.

When I was visiting Bend Oregon, the riding was so smooth that my 5 inch XC bike was a rather silly choice and I would rather have been on a rigid (no suspension) bike.

In the end the choice is a personal one and the cost/benefit will be different for every rider.

Injuries

Injuries really depends on a combination of your bike handling skill, your riding terrain, and your risk tolerance.  There is also the probability of crashing combined with extent of injuries.  Full suspension often lets people ride harder terrain than they might otherwise, which has potentially bigger consequences. Anecdotally, I have observed those with the most suspension also tend also to have the biggest injuries.


How do you make the handlebar stem straight?

A problem many hit when trying to straighten the stem is that they end up aligning the stem with the bike while the wheel is almost straight. A degree or two isn't noticeable until you are riding and then it really bothers you.

Instead of trying to align three things (bike, stem, wheel), turn the wheel about 45 degrees. Now align the stem (I generally do it with the wheel trapped between my legs and the bike in front of me) to the wheel. It's much easier to ignore the bike when it's not even close to in-line.

Happy riding.


What bike+equipment for a long daily urban commute?

Here I'll summarize everyone else's answers (because of all the Q+A scattered through in the comments), with some additional information that I got elsewhere from reading inspired by people's answers.

Wheels+tires: 700 x (28 - 38, maybe ~30), tires; slicks or light treads, not knobbly. The larger wheel makes it faster (because of 'gearing') and the ride a little smoother (because of the 'angle of incidence' when rolling over an obstacle). Possibly puncture-resistant tires, especially if you experience many puntures. Reinflate them weekly. With the narrower tires, beware storm drains, streetcar tracks, dirt roads, and cornering especially fast and on wet roads.
Clipless pedals and shoes: up to 35%-50% more efficient than without, but practice with them for 1/2 day to 2 weeks away from traffic first, because you must expect to fall off (everyone does). The normal type of clipless, for commuting, would be SPD: SPD are not impossible to walk in (unlike some other types). The stiffer the sole of the shoe, the better it distributes force over the whole sole of your foot. {Prefer a system which lets you clip onto either side of each pedal?}
Gears: multi-speed (e.g. 7, 8, or even 14-speed) internal-hub gears cost $300+ (which is more than derailleurs), and tend to exist only on more expensive (above $1000) bikes; internal-hub gears means lower maintenance, chain is less likely to fall off, easier to have a chain guard even, and you can change gears while stopped, maybe 2% less efficient that derailleurs, and takes a different kind of chain. Derailleurs are more common. A 2-position rather than 3-position derailleur on the front would be adequate if there are no hills.
Handlebars: as you wish (however, many/most people recommend flat instead of dropped); at commuting speeds it's more a matter of comfort than aerodynamics (and a more upright position is deemed more comfortable). Dropped affords more wrist positions; you can ask for interrupter levers on dropped handlebars, to access the brakes from more than one hand position/location.
Brakes: disc brakes work better or more reliably than rim brakes, especially when the road is wet (or the wheel isn't true); and if you go downhill at 70 kph you might want hydraulic disc and not just mechanical disk brakes (hydraulics are more expensive, are difficult or impossible to self-maintain, require less or no maintenance or routine cable adjustments, and require less finger-force to actuate).
Frame: not too important i.e. no-one offered advice on that; as long as (for speed) it's not a mountain bike, especially not a bike with suspension (suspension is inefficient). Aluminium isn't lighter than steel, because it's not as strong (and therefore there needs to be more of it). Aluminium is stiffer than equivalent steel, so (for comfort) higher-end bikes add (more expensive) carbon forks and/or seat posts to aluminium. Aluminium won't rust.
Other equipment: lights; fenders/mudguards; rack and/or saddlebag and/or panniers; bike lock[s] (maybe one chain and one U-lock: not a cable, which is easy to snip); maybe mirrors (you can/should shoulder-check as well, but many/most urban bike accidents happen while the rider isn't looking ahead); maybe a trip computer; a tire pump, able to inflate to about 110 psi (so not just a little hand-pump); bus fare (in case of a flat or irreparable tire, or horrific weather).
Store: find a "good" Local Bike Store (LBS), where you can meet the mechanics (a "good LBS for commuting" isn't necessarily the same as "good for road-racing" or "good for MTB"). Pretty much any decent LBS will allow ~30 minute ride: take a few for a test-ride, before you buy, to see which one feels right. Furthermore, expect to pay at least $600/year in maintenance costs (as much or more than the cost of buying the bike), visiting the shop at least 3 times/year: which is another reason why it's important to find a "good" LBS.
Speed: expect to average 20 kph at most, in the city, when there are stops and lights etc.
Cost: a decent $700 (including brakes and gears but perhaps excluding 'extras' like lights) bike from a good store should be "great" (but it won't have internal-hub gears, nor hydraulic disk brakes, nor any carbon components)

Additional comments or advice will be welcome.


How to safely remove pump off presta valve?

I used to skin my knuckles every time I took the chuck off the valve.  Then I figured it out (pain is a learning curve accelerator).

Position the wheel so the presta valve is closest to you and pointed away from you.  Use your thumbs on either side of the wheel to push the chuck straight off (toward the hub of the wheel).

This prevents the presta stem from being bent/broken and limits how far you hands can move when the chuck pops off.  No more bashed knuckles.


Where to find good bicycle maintenance info?

A Bit More Than Basic Bicycle Maintenance for the Average Cyclist, at the How to Fix  Bikes
Sheldon Brown's site has articles on many aspects of bike maintenance
The Park Tool website has instructions for most basic repair operations, and their handy bike map is great when you don't know a headset from a handlebar.
Bicycle Tutor has videos demonstrating many repair jobs
Beachbike's Youtube channel has a lot of information specific to beach cruisers. The videos on internally geared hubs are helpful and clear.


What is the best bicycle lock on the market?

Some years ago, Bicycling magazine did a shootout on available locks and the Kryptonite "New York Chain" came out on top.  Unfortunately, it weighs more than many bikes and is not easy to carry either.
Fine if you can leave it where you lock your bike.

I'm with the police department at a major university, and we have a program through Kryptonite where we give the kids a (heavily subsidized) Kryptonite U-lock for a mere 20 bucks.
Over the 30 years I've been here, we've had only a handful of these locks defeated. Most all the bikes we have stolen (lots...) are locked with the sort of cable shown above.  The thief uses a rather small bolt cutter and removes it more rapidly than you could by using the combination.
The U-locks are easy to carry, not overly heavy, and offer a "good" level of security.

Anything can be defeated with the right tools, time, and opportunity.  Deny the thief these things and you have a better chance of hanging on to your bike.
Or....Buy a beater and save your nice bike for weekend rides.


Product req questions are now Off Topic.

So you need to figure out what you want from your new saddle.

Start by measuring the width of your existing saddle, right where your sit-bones make contact.  Then use the cardboard or rice-sack method to measure your physical anatomy.    This will give you a number in millimetres.

Then look at the general shape of your old saddle - is it pointy?  Do the sides flare out late or early?  You either want a saddle that matches the overall shape, or tweaks any area that you feel could be better.

A new saddle is a chance for you to try a slotted design in the middle, should you suffer from numbness.

Finally the padding and covering are important too - your old saddle will probably not be worn out given it was a rail that broke.  So squish it with your thumb and try to gauge the thickness.   The covering is 90% likely to be some kind of vinyl or plastic.  If you like it, duplicate that.  If you don't like it, consider what else is available.

Now you say your bike only cost you $50 of your currency.  There's an implicit "...so I don't want to spend much money on it" and I disagree with that.

The saddle is one of the three contact points between you and the bike, with the pedals/feet and bars/hands being the others.   I'd have no problem buying some good shoes or pedals or bar grips for a bike.

Saddles are generally more difficult because they are quite hard to trial.  Some cities in the world have saddle libraries where you can hire a saddle for a month for a small fee, ride it, and then swap it for another one.

Leather saddles are even harder to trial, because they conform to the rider over time.  So they're somewhat like 10 pin bowling shoes.

Remember, any part can be removed from the bike and used elsewhere, so a nice saddle can be swapped onward if you break the bike.

Also ask around some other cycling coworkers, or check your city for a bike cooperative.  I have a number of spare saddles that I'll never use, which have turned up from bike teardowns or clearance sales.


Mountain Bike has 26 x 2.125 Tires on, Can I Fit 26 x 1.95?

Yes - you can fit 26x1.95 tires to replace 26x 2.125.  They will be slightly narrower, and that might mean you need to pump them up slightly harder.  If the tread was the same pattern, they would probably offer slightly less grip on a loose and rough surface, though it is likely that the new rubber will be much more grippy than your old tyre is.


A Gates drive belt uses an 11mm pitch between teeth.  A conventional bike chain is 1/2 inch or about 12.7mm.

The upshot is that for the same tooth count, a drive belt component will be slightly smaller than the comparable roller-chain unit with the same tooth count.

Good news - since the front chainring and rear cog use the same size, then the ratio is all that matters, and you can use all the normal formulae to figure out cadences.

The Shimano Alfine 11 has these ratios:

Ratio   0.527   0.681   0.770   0.878   0.995   1.134   1.292   1.462   1.667   1.888   2.153
Step        29.2%   13.1%   14.0%   13.3%   14.0%   13.9%   13.2%   14.0%   13.3%   14.0%

So assuming your sprocket is 24 tooth that equates to an 11 speed cassette with these tooth counts:

12.6, 16.3, 18.5, 21.1, 23.9, 27.2, 31.0, 35.0, 40.0, 45.3, 51.7

I couldn't find a nice calculator that deals with non-whole teeth, so I've rounded to these numbers instead.  Loss of precision detected.

13, 16, 19, 21, 24, 27, 31, 35, 40, 45, 52

I've also assumed a 28mm tyre with a 700c wheelsize.

Poke these numbers into http://www.bikecalc.com/speed_at_cadence  and you'll get this table:

If you put the same info into http://www.bikecalc.com/cadence_at_speed then you get this table:

ANSWER: on a 50:24 gear combination, with an 11 speed Shimano Alfine hub and 28-622 tyres on a 700c roadwheel, you will be doing about:

30 km/h in gear 9 with a cadence of 89
30 km/h in gear 8 with a cadence of 99


In my personal experience I've found that front derailleurs make little difference to the shifting. I have noticed very little difference between my new Ultergra, my 15 year old daily Tiagra and the 2nd hand supermarket bike to leave at the train station in the morning.
Front derailleurs should take very little time to set up as they are simple brute force devices. Poor performance comes from sticky pivots after years of neglect and generally worn cables.
If you are set on replacing I've linked to the Sheldon Brown article which should give you some details on how to identify what you have so you can find something similar to replace with


As far as the increase in drag after a few weeks, I reckon the Chain-L oil is to blame for that. As far as oils go, it's not all that heavy, and over a few weeks can migrate out from where it needs to be inside the freewheel.

One of my favorite things to do with an old free wheel is to soak it in degreaser/solvent/parts washer overnight. Then, use rags and compressed air (or opening it up, if you like tiny bearings in abundance) and clean out the degreaser. Once the freewheel is bone dry, slowly dribble in some Phil's Tenacious Oil while spinning it. Ill often set the freewheel onto a freewheel tool in a vice and spin it with one hand while holding the Phil's bottle in the other.

The dry freewheel will ratchet very loudly, but you'll hear it quiet down as the very thick oil begins to penetrate. Once you start to see some oil come out the other side you know you're done.


Does Cycling Cause Erectile Dysfunction and Sterility

I'm confused by the diametrically opposite views.

My answer will attempt to explain why you may see "diametrically opposed" views on these types of subjects.

For a summary of evidence on ED and male fertility see answer: Can cycling adversely affect male fertility?

Quality of data

The strongest scientific inferences come from studies where you can randomly assign treatments to your experimental units (i.e. people in this case). The randomization is key as there may be all sorts factors (some we may know about, others we may not) that may impact the measured response (e.g., prevalence of erectile dysfunction).  Randomization will, on average, even out these effects.

The problem with epidemiological studies - studies of  health and disease in human populations - is that it is generally not possible to randomize treatments, instead researchers rely on "natural experiments" to do the treatment randomization for them.  For example you cannot go out and gather a random selection of people from your population then assign them a treatment such as cycling for the next 6 months at a rate of 0, 5, 10, 20 hrs a week, so that you can measure the rates of erectile dysfunction (ED) or changes in sperm count.

Rather you must rely on people who have essentially self-selected these treatments.  Are there other factors associated with whether or not a person may be chose to ride 0, 5, 10, or 20 hrs per week?  You bet!  Could those factors also be linked to ED or sperm count - sure.  If we know exactly what factors could be influencing the response we can potentially control for these statistically.  The problem is that their may also be factors we simply don't know about, termed lurking variables, and there are numerous examples where they have mislead interpretation until discovered.  A simple example is that shark attacks are correlated with ice cream sales - sharks love ice cream!

Furthermore, you also rely on subject self-reporting, which can result in issues such as reporting bias.  For example, ED has been a long discussed issue in cycling circles.  As a researcher interested in ED and long distance extreme cycling you survey a bunch of riders after a long event.  Then ask them to self diagnose these issues. The fact you (as a subject) have heard about these issues before, and now you have a researcher asking pointed questions can bias your response.  That time you were thoroughly exhausted and just wanted to sleep could get categorized as impotence (because you are concerned), when in fact it might just have been exhaustion.  We don't know because most of us are not trained physicians who can accurately diagnose these issues.

Interpretation

All of these different factors can result in spurious results (a "statistically significant" effect that is essentially a fluke) in studies, especially small studies.  Since this is a "sexy" topic any study finding an effect (spurious or otherwise) will quickly make the media rounds, which will quickly make the facebook rounds and have people talking.  Once a "fact" is out there it can take a long time to repeal (don't get me started on vaccination - the single study often quoted as evidence against vaccination was long shown to be a fraud study).

These factors can quickly lead to diametrically opposed views getting air time and the general public being confused.  For a great overview of this see John Oliver's rant on science and science reporting.

What can you do

View any single study with great skepticism - it could be flawed or the results could apply under a very strict set of conditions.
Look at the effect size - some times it may be significant, but the size of the effect is small.
Population averages do not necessarily translate to individuals (aka ecological fallacy;  (e.g., the population may ride BSO with horribly uncomfortable saddles, that aren't set up correctly)
Finally, look for "meta" studies that are over viewing the current state of knowledge  looking for the weight of evidence.  For example if 20 studies exist and all point to a large ED then I would be pretty damn concerned.

The other related answer (Can cycling adversely affect male fertility?) does have one such study (Leibovitch and Mor, 2005), that suggests:

  Urologists should be aware that bicycling is a potential and not an infrequent cause of a variety of urological and andrological disorders caused by overuse injuries affecting the genitourinary system.

Unfortunately the full article is behind a pay wall so I have gotten my hands on it yet.


Mavic wheels out of true after 200km, is normal?

It is normal for a new rim to be out of true after first rides. Once the first service for the rim is done, it should remain true for thousands of kilometers.

It is recommended to check a new rim after 200-1000 km of riding.

I recommend using a professional mechanic to true the wheel. It is easy to overtighten some of the spokes, if you don't know exactly what you are doing.