Purpose of locknuts+adjustable nuts on sealed hub bearings

The straightforward answer is their purpose is to establish bearing preload, they should be adjusted so that the hub bearings are as loose as possible without play, and they should be tightened against one another to  about 15-17 Nm. (Those are Shimano's generic values but the same numbers can be used pretty safely for locknuts on pretty much any steel hub axle. If you don't have a torque wrench, or the ability to get one on there, just making them nice and tight is fine.)

Usually on hubs like this you're tightening the pair of nuts on each side against one another to lock the adjustment in place. If you were to instead to tighten the inner locknuts (the ones that contact the bearing inner races) down towards each other and then outer locknuts down onto them, you'd tend to end up with a preload adjustment that's too tight.

In reply to the edits: on one side, turn the locknut finger tight against the bearing, then lock it in place with the other locknut. Repeat for the other side.

As to what is the purpose of them, there's a significant hub design element to this question, in that there are many cartridge bearings hubs with no adjustability, where on either side a single nut or endcap pinches the bearing inner race against a shoulder on the axle, instead of a hub like this with preload adjustment via a pair of locknuts. A few hubs like the one pictured use what's called an angular contact bearing and have unshouldered (aka standard) axles, and therefore need the locknuts so they have some way of establishing preload, but most have shouldered steel axles.

I don't know what a hub designer would say about it but I suspect that a reason why a lot of nutted BMX and track hubs with shouldered steel axles are like this is that with only a single locknut per side, it would be too easy for those locknuts to come loose in the process of loosening and tightening the axle nuts. They also may be something of a perceieved insurance policy against tolerance issues between the bore-to-bore spacing on the hub shell and the shoulder-to-shoulder length of the axle, because then even if the axle shoulder spacing is a bit under at least you can use the locknuts to have one inner race be pinched firmly between shoulder and locknut while the other inner race floats on the axle.


I though about it long and hard and consulted a friend who works for yeti in manufacturing. Figured there is some margin for manufacturing tolerance and factor of safety.

Filing worked like a charm. Wet sanded and polished the cut afterwards and it looks great. I figured the only real worry at that spot on the caliper is structural support in case of a crash, but its protected behind the seat stay, so a little less is probably not an issue. Besides, this is the kind of material removal that might happen in a crash.

Cleaned it all up with isopropyl alcohol, toothbrush, and compressed air afterwards.

I may put some color match paint on there at some point.

Doing this was ultimately up to me and to the average person I wouldn't recommend this, but I knew I could do it well so I went for it.


Why are tires that fit 622mm wheels called 700C

As stated in this answer or this link, the idea was originally that there were 700A,700B,700C tires+wheels which all had an outer diameter of 700 mm with A tires being the thinnest and C tires being the thickest (so A had the largest rim and C had the smallest rim). Eventually, the C variant won out, and people varied the outer diameter by mounting different tire sizes on a 700C rim.


could I mount a different manufacturer brand rotor to use with my brakes?

The brand of brake doesn't matter. The only variables you should care about are:

Rotor diameter. You should probably get the same size as the old one; for a different size, you'll need an adapter to reposition the brake calipers.
The way the rotor attaches to the hub. Most of them are held on with 6 bolts, but a few use the "Centerlock" attachement which looks like this:


There are 10 speed compatible chains starting around $20. However, most shops, in order to limit the number of different items they need to stock, will only stock higher end chains, usually 105, Ultegra, Dura Ace, and SRAM's PC-1071 and 1091r.

Which are more expensive, but have the advantage of being compatible with any 10 speed drive train.

Most likely, there is some difference in price because 10 speed technology is only just starting to move to the most basic of quality bikes, and there hasn't until recently been a need for a low price/basic quality option for 10 speed.

9 speed was the same way. It will get better, as the need for low end 10 speed gets more universal.


How to add resistance to my bike trainer?

This is the powercurve for the Cyclops 2 fluid trainer

You can see that at 30mph on the trainer you'll need to be producing around 400 watts. Using this website

http://www.machars.net/bikecalc.htm

46x11 will give you 30mph at 90 rpm (which is a reasonable rpm for home training). 400 watts is like a Pro climbing l'Alpe d'Huez. Note also that the power curve is exponential, every extra mph gets progressively harder. At 35mph you are in the 600-700 watt range.

Fluid trainers take a while to warm up - 5 to 15 minutes but generally offer more resistance while they do.

So I agree with the other posters, your unit is faulty in some way. If not, you should contact a Pro team for a contract.


As @Kibbee has stated the IGHs do have a different OLD, although Nexus hubs can be spaced out to 135mm with spacers/ bolts/ washers.

You need to measure the Dahon's rear dropout spacing.

I can't find anything to suggest otherwise so I assume it's 132mm, in line with other commuter type bikes.

The limiting factor is dropout spacing. The Dahon is an aluminum frame with short chainstays. Both of these essentially prevent the ability to spread the dropouts and force a wider hub in. Aluminum is brittle and not malleable like steel, it doesn't like being bent.

You may damage your frame and void the warranty.


How do I use a freewheel as a single-speed?

There are multiple options.

Just use one cog and don't change gear.   Cheap and easily reversible.
Remove and store your rear derailleur/shifter/wires, and then trim your chain to length so it only suits one cog.  This may require a chain tensioner and risks dropping the chain off, if the chain line isn't good.
You can get single-speed kits that fit on a freehub, essentially a cassette with one cog and spacers for either side.  Since the horizontal placement is adjustable, you should be able to get a better chainline.  If you only have a freewheel, this is not an option.
The expensive solution is to get a single-speed wheel, or rebuild your existing rim onto a single-speed hub.   This may give you a flip-flop setup where each side of the bike has a different gear, or the choice between a fixed-gear and a single speed.

It really depends if your frame has track ends (probably not if it has a derailleur) or some other way to set the chain tension.

Remember you still absolutely need working brakes, front and rear.  Don't remove them in your quest.

Personally I just ride with my gears - the 1935/6 Tour de France riders petitioned long and hard to be able to use gears!


Recommended inexpensive heart-rate monitors?

I can't speak about HRM's that do not use a chest strap as that's the only type that I have used (other than to play with in the store).  I find the ones with a chest strap to be completely hassle free, and I don't have to contort into a weird position to get a reading.

I've had great luck with HRM's from Timex and Nashbar in the $50 range, and like Polar but have never owned one.

If you do go with a chest strap type, the primary thing to watch out for in the lower-end range is the ability to change the strap battery.  Some have a sealed chest strap, so you either have to tear it apart and super-glue it back together, or replace the strap entirely.


Any special issues with putting a wider internal gear hub in a narrower alu frame?

Do not use a mis-matched internal geared hub for your frame.

You risk damage to your gear hub, your frame, or both. Aluminum frames are much stiffer than steel frames, which is good for good for riding, but it is also prone to cracking due to this stiffness (when compared to steel's malleability). Even if you do fit the part, it will be a weak point in the frame.


What is the best method to teach a young child to ride?

You're absolutely right--children's bicycles with training wheels are good for exercise and entertainment, but they do little to nothing for balance.

In my experience, the best way to teach anyone--children included--to ride a bicycle is to take the pedals off, lower the seat, and let them scoot & coast around until they develop the proper balance. Then, add the pedals, and let them coast, pedal, etc.

For children, there are several popular brand that makes 'run bikes', which are usually made out of wood, and have neither training wheels nor pedals. They are low enough that the child can sit in the saddle and place both feet on the ground, but high enough that they can still propel themselves & lift their feet to coast.

These bikes allow the child to quickly and safely develop good bicycle balance.

(See http://www.earlyrider.com/, http://www.runbikes.com/, and http://www.likeabikeusa.com/)


How can I find the year of these Giant XTC 2 bikes?

bikepedia.com has a lot of data, sometimes a bit incomplete. https://www.bicyclebluebook.com/ is my other quick-n-dirty go-to site.  Take the values with a grain of salt, since the virus-caused biking craze has driven up prices on everything bike-related.
Looks like those bikes might be 2008 or 2009 Giant XTC2s, although truvativ is listed as the stock crankset, and the color pattern seems to be the inverse of the one listed. I've noticed in these refs that alternate color patterns are often not listed, and bike shops often swap in/out parts on new bikes to fit customer preferences.  The stock rims are listed as WTB in 2008 and Mavic in 2009.
They look good to me -- solid entry-level hardtails; what would you try to achieve with "upgrading" versus just making sure the drivetrain etc components are functional and in good shape?
(based on updated info from OP)
The Dart 3 IS a basic entry level fork (but not an even cheaper "fork shaped object") and IIRC uses a coil spring rather than a fancier and much more expensive system like an "air shock".  You would spend many hundreds of dollars to move up to a significantly better fork; at this point, I would just ride the bikes. You'll learn how to do basic maintenance, and certainly identify features/quirks of the bike that you do like, and some you don't. 6 months or a year down the road, you'll know what type of riding you like, and have an idea of what bike features will support that. Then you'll be able to make an intelligent decision on what to do with these bikes or perhaps get another.
Here's what I would do:

Certainly get a new chain; keep the old one to line up with the new one so you can shorten the new one to the correct length.
Clean off the front derailleur (and rest of bike), but FD function is usually not affected by surface rust.
Have someone with knowledge evaluate whether the front chainrings and rear gear cassette are worn and need replacing along with the chain. Have them evaluate whether the shifter and/or brake cables need replacement. Have them evaluate whether the tires are safe or need replacing. Have them evaluate whether the wheels are safe or need fixing. This is an excellent opportunity to find a Local Bike Shop (LBS) that you can trust with questions and fixes beyond your knowledge. A "bike tune up" should cover most of these questions, but replacement parts will be extra.
Get grips, pedals and a saddle that you like. They're all straightforward to install, but getting the old pedals removed and new ones installed is much easier with a big "pedal wrench" which will run $25 or so.

Books I've found helpful and easier to use next to the bike than a tablet:
"Zinn and the art of Mountain Bike Maintenance" You can save a lot of money by getting the 2010 (earlier) edition, which still covers all the technology in your 2008/2009 bikes.
"The Bicycling Guide to Complete Bike Maintenance" by Downs (also cheaper as the previous edition)


How can I install a front brake on this kids bike?

Do not install a front brake to a bicycle that has not been designed for front brakes!!! A front brake requires a frame strong enough for front brake and a fork strong enough for front brake.
There is a quite popular bike sold in my area called Helkama Jopo. It used to be a coaster brake bike with no front brake.
Then, at some point of time someone working for Helkama thought it would be a good idea to switch the steel material of the frame to aluminum, and at the same time install a front brake. Unfortunately they did not design the frame to withstand the loads of a front brake.
The bikes started to fail (the frames cracked and separated in half during use). Some failures resulted in tremendously hurt riders injured for the rest of their life.
The manufacturer claimed that these failures were the result of incorrect use, i.e. jumping and doing wheelies with the bike. Not so!
There is a post in LinkedIn by a mechanical engineer analyzing the issue: https://www.linkedin.com/pulse/miksi-jopo-hajosi-vesa-tiainen
Unfortunately the post is in Finnish, but the mechanical engineer showed that the failures were not due to incorrect use such as jumping and doing wheelies, but they were caused by the manufacturer's decision to install a front brake.
The manufacturer probably realized the mistake, and later front brake versions of the bicycle contained a slight alteration in the frame to prevent peak loads.
The manufacturer still today lies that wheelies and jumping were the cause even though they did a fix to the frame to allow front brake usage, and thus clearly understand that front brake caused peak loads in one part of the frame.
Your frame seems to be exactly the same type as Helkama Jopo, i.e. there are no separate top tube and downtube attached to the headtube. Instead, the top tube and downtube meet earlier and the unified tube attaches to the headtube. This design has exactly the same flaw as the Helkama Jopo design.
Your frame is not strong enough to withstand front brake loads!!!


Is it possible to mount a disk brake hub to a rim-brake rim?

There's no problem mounting a disc-compatible hub to rim-brake compatible rim. Just make sure they've got the same number of spokes and you're good to go.

You're absolutely right about the opposite though, disc brake rims generally do not have a braking surface on them, the rim profile is round there, so it wouldn't work. And if you did try to brake on it, it a) wouldn't work well and b) would probably cause excessive rim wear.

What you could do, if you want to be flexible and switch back and forth is to get a dual-duty rim that supports both, such as the WTB Dual Duty FR rims (probably a bit beefy, but you get the idea).


Converting Sram Force 22 crank to Force 1

First of all, you absolutely don't need to replace Force 22. The crank arms have removable direct mount spider that the chainrings are bolted to. That means, in theory, you can put almost any chainrings given a matching spider exists - a very versatile system that's gained popularity over the recent years (Red/Force AXS are direct mount only, unlike Red 22).

If I just swop the rings for the a narrow wide Sram Force 1 chainring
will this automatically fit into my existing crank arm?

Also if I do just replace the rings, would I need smaller chainring
bolts or will the existing ones work

If I were to convert Force 22 to 1x, I'd check the following:

For regular chainring (mounted to spider), BCD (bolt circle diameter) should match. Force 22 came in 110mm and 130mm varieties. BCD limits minimal chainring size - the bigger the BCD, the bigger smallest compatible chainring is.
For regular chainring, chainring bolts should be compatible. Bolts are two-piece (nut and bolt), some are single piece (bolt screws into chainring). You can visually inspect existing bolts to check what you have, I don't have hands-on experience with Force 22 in particular. With a single chainring, the bolts might be too long and require spacers.
For regular and direct mount chainrings, you might want to factor in chain line (determines relative positions of cassette and chainring centers). For 1x road/gravel applications, it should be relatively safe to put the chainring on outer ring position, at least in my experience (I run 1x setup on my road bike with 2x crank arms). Spider design (I suspect Force 1x spider might have different offset/chainline to that of Force 22, but I can't say for sure), spindle length/interface and rear hub width (130mm non-disc road, 135mm QR/142MM TA, boost and so on) affect the chain line too. Force 22 can have GXP and BB30 spindles (there are true BB30/short and long BB30/BB386 varieties, at least for S2200). I only have experience with SRAM S2200 arms (very similar to Force 22, if not the same), when I was in market for a 1x chainring, this was an important factor. Direct mount chainring manufacturers usually specify what spindle/hub width the chainring is for. The spindle type is written on the spindle, the length can be measured with a ruler.
For direct mount chainring, take a note of chainring interface. There are a lot of varieties, but Force 22 has the 3-bolt Truvativ/SRAM pattern. Newer SRAM offerings have different interfaces.

Personally, I'd swap the whole spider assembly to a direct mount chainring because it looks cleaner. See manufacturers like Absolute Black, Garbaruk, Wolf Tooth and many others.


Compatibility between 4700 Tiagra 10 speed shifters and GRX RX400 10 speed derailleur

Looking at Shimano's Compatibility Document one can see that indeed, Tiagra ST-4700 brifters are compatible with their rear derailleur model RD-RX400.
Can't blame you for wanting to stick with rim brakes.  Although hydraulic disc systems are not as complicated or difficult to work with as it may seem, there are some negative aspects that (IMHO) make a quality rim break quite competitive with disc brakes.  From a cost stand point--both initial and continuing maintenance-- rim brakes have a lock on value.  The relatively minor edge on performance disc brakes have is a fairly costly one.


I probably don't do "proper" track stands since I don't ride a fixed gear bike, but if you can find a bit of a hill at a stop then you can kind-of-sort-of do a track stand (you pedal up the hill and let gravity pull you back down). Sometimes the crown of the road is enough…

That said, I always sit, I didn't know you were supposed to stand, so I'd say keep working on it!


What are the advantages and disadvantages of a cycling desk?

The basic answer is that there are many studies that link exercise and brain function.  A standing desk will get you off your bum, but a treadmil or cycle desk will get your body moving enough to allow your brain to work better.

There is an entire chapter in the book Brain Rules.  I have no personal experience with it, but that is the theory.


dropper post not working at freezing temperatures

The reverb, much like Shimano brakes, has a known issue when operating in the cold. The oil inside simply thickens too much to properly flow through the lever and hose. The oil flow through the damper also gets constricted. I don't think there's really a solution because switching to a thinner oil might cause issues in the summertime, such as the post rebounding too quickly and damaging internal components. Of course, you could switch to a different dropper with a more modern design that does not suffer from that issue.
Do NOT pull up on the reverb when it is compressed, even if the lever is being pushed. You will suck air past the seals and cause the infamous "Reverb squish" (where the post is no longer capable of staying rigid thanks to air being mixed in with the oil, and you basically have a very expensive suspension seatpost. Cannot be fixed with Viagra.)
Edit: If your particular model has it, try turning the speed adjuster to full open/fastest. That might help.


How should the chain be routed on this deraillier?

You almost made it...   Obviously bottom long line should run straight to crankset.  You will feel some spring tension when you route the chain.


My front wheel was steering to the right... now it's steering to the left. What's the cause of this?

Factors that have an impact on the steering include external forces and internal forces. External forces include things like cables, the riders centre of gravity and forces coming from the wheel (out of true, dead hub bearing). Internal forces have to do with the headset itself, if the bearing cups are not parallel, if the adjustment is incorrect, if a foreign object made its way into the headset, if there is pitting in the bearing cups. A bent steerer could also be it.

If you have eliminated the cable pulling (or pushing) as a problem, and your wheel is true, try adjusting the headset bearings. They should be as loose as possible without having any play or knocking. A dead bearing on one side of your hub would probably have a negligible contribution. If you've done that and it's still a problem, I would suspect the seating of the bearings not being parallel or the
 steerer tube not being perfectly straight.


Raleigh Motus Tour 2018 - Chain electric bike replacement

Any 9 speed chain will do, of those two, one claims anti rust, the other not. For a well maintained bike, it makes no difference (except maybe cosmetics).

If the bike has a hub motor it makes no difference as no power is transmitted though the chain.  If the drive has a mid-drive motor, power is transmitted though the chain, but there is some debate if there is debate over if the label 'e-chain' is more than marketing.

An elite rider can output well over 1000W vs 200-300W for a ebike, so strength of the chain to handle high load is not the issue, any bike chain can handle the power of an E-Bike motor. In terms of torque, similar argument - torque of a 100kg rider standing on cranks is 175Nm, and an elite rider can probably double that momentarily, while most eBike motors produce half of that.

Wear is likely impacted as you ride further and mostly importantly, faster on an ebike. Chains wear out, that is a given. How much faster a 'normal' chain wears out over an ebike chain, and cost and inconvenience of replacement,  is the reason to go an ebike specific chain.

Personally I would not pay a premium for an Ebike specific chain.


Shimano Sora 9-speed shifters "missing a speed"

I'm kind of confused here. You say you can only click 8 times. On a 9 speed bike, there would only be 8 clicks for shifting.  Let's say you start on the largest gear, and we'll call that 1.  Clicking 1 time with bring you to gear 2. Clicking 2 times will bring you to 3. Clicking 3 times with bring you to 4. Continuing on with the pattern will bring you on to clicking 8 times to bring you to 9.

If you bike was skipping a gear somewhere in the middle, you would shift 7 times, and already be on the smallest gear, and shifting one more time would bring you nowhere, as you would already be at the bottom. The limit screw would keep it in it's place, and the cable would go a bit slack. Going up the cassette you would notice a problem where you still had 1 click left, but would be unable to move the shifter because you would be pushing against the limit screw.


Steering in pivoting boom front wheel drive recumbent bike

I've built one and ridden a couple of commercially made ones (Cruzbike and a European one) and I have not been very impressed. That design has never done very well at our local races, for example.

That's the prototype we built that convinced me it wasn't a design I wanted to go further with. It was quite rideable but there wasn't enough great about it to make it worth choosing that design over something more conventional.

As far as slalom racing goes, you'll obviously be trying to build something lower and more reclined than I did, possibly like the CruzBike RAAM bike. I think it will be worse in the slalom than a fixed bottom bracket bike because pedalling while turning is harder, and at sharp turning angles is impossible. The main problem is not so much the funny angles between the pedal and your ankle, but that the inside leg is pushing out on the steering, while the outside leg is wrapped around the bike and pushing in. That makes pedalling in circles basically impossible so it is very hard on your arms (and the handlebars have to be beefed up to take the extra forces).

There are a lot of recumbent designs out there, even if you limit yourself to two wheels. I suggest looking around the homebuilder sites and maybe going to a traditional highracer style SWB bike. The RAAM CruzBike is effectively a highracer, but a steep seat one rather than laid back. Those are pretty easy to build and do better in slaloms than the really low lowracers do (higher CoG means there's less mass moving around the slalom cones).


Why recover with carbohydrates, instead of with protein?

This answer is primarily based on 2 books by Chris Carmichael. The Time Crunched Cyclist and Food for Fitness, plus some other sources that I am unable to dig up at the moment.

Here's the gist of it... Following a race, intense workout, or an endurance ride, the muscles and liver are glycogen depleted. The key to recovery is to replenish glycogen so that you begin your next event with full glycogen stores. The major building block of glycogen is carbohydrate. The body quickly and easily disassembles carbohydrates into glucose and that glucose is readily available for conversion into glycogen by both the liver and muscle cells. Protein is synthesized into glycogen, however protein must be first transported to the liver, converted to glucose, and then transported to the muscles. So, restoring glycogen levels with protein is less efficient and more prolonged than restoring glycogen with carbohydrates.

According to Carmichael, the 3 critical components post-ride are carbohydrate, sodium/electrolytes, and fluid. And, your body is primed to replenish muscle glycogen stores most rapidly within the first 30 to 60 minutes following exercise, and the sooner the better. As GuyZee points out in another answer, "the glycogen window".

Back to protein... Protein is also important for recovery, primarily for muscle tissue repair and additionally protein enhances the ability of muscle tissue to utilize carbohydrate in the replenishment of glycogen. A general rule of thumb is a 3:1 carb to protein ratio; but some experts recommend a 4:1 ratio.

In essence:
Carbs for glycogen replenishment.
Protein for muscle repair.
Electrolytes and fluid.

Examples... One would be something like a bowl of rice and sauteed vegetables plus chicken breasts. And for a "technical" product, something like Recoverite by Hammer Nutrition. I personally like the Hammer products as they don't use sucrose and high fructose corn syrup; instead a primary ingredient is maltodextrin which is basically long chains of glucose. Sometimes I don't have time for an actual meal, so I'll use Recoverite in that case. It can also be chocolate milk. The basic idea is that you need to replace and repair.

FWIW - None of this matters for the casual cyclist or the "typical commuter". Just eat normal, healthy meals and you'll be fine.

A few references:

REGULATION OF MUSCLE GLYCOGEN REPLETION, MUSCLE PROTEIN SYNTHESIS AND REPAIR FOLLOWING EXERCISE (International Society of Sports Nutrition Symposium)
RECOVERY - A CRUCIAL COMPONENT FOR ATHLETIC SUCCESS (Hammer nutrition)
How to Plan Post-Exercise Recovery Meals (livestrong.com)


Can a broken/split chain be reassembled?

Fifteen years ago the answer was a simple "Yes". Today's 10, 11, and 12 speed chains are not designed to be reassembled this way, and in fact, will reliably break or fail where you reuse the rivet. For these new narrow chains, simply use a replacement rivet on Shimano, or master link on SRAM or other.

For older bikes, or chains designed for 9 or fewer rear cogs, see below:

The same tool that you use to break the chain can be used to push the rivet back in. The trick is to make sure that you don't pop the rivet all the way out--it needs to stay in one of the sideplates. A lot of chain tools will stop automatically before they pop the rivet all the way out.

Alternatively, you can remove the rivet entirely, and the outer half-link, and replace that with a master link. You can get individual master links. These need to be sized to your chain (so if you have a 9-speed drivetrain, you'll have a 9-speed chain, and need a 9-speed master link).


Netherlands: where to buy cheap bikes? (Police autions, cheapest towns)

There are several places to avoid if you are looking for a cheap bike, and several places to seek.

First to avoid:

Generally bikes tend to be pricier / lower quality in all towns with a big university because demand is high and many bikes are "consumed" by the buyer. Lots of exchange students buy a bike and discard it after a year rather than resell it, and most other students use their bike untill it falls apart with as little maintenance as possible and discard the wreck. So you're less likely to find a good value bike here: Groningen, Enschede, Wageningen, Utrecht, Amsterdam, Nijmegen, Maastricht, Eindhoven, Tilburg, Delft, Leiden.
Regular bicycle shops (they usually charge a high markup for secondhand bikes).

What to seek out:

As a counterpoint to the point about university towns above: in many of these university towns you get people who collect the wrecks and combine them into working bikes that they sell for a nice price. You'll find these people through marktplaats and they offer reasonably priced bikes.
the "Kringloopwinkel" or "tweedehands winkel" in whichever town you select (second hand store). They are quite often the party that receives "left over" bikes from the police and bikes removed for being "in the way" (which I explained in my answer to your previous question)
www.marktplaats.nl (with an "s") is a good source of cheap secondhand bikes. There is no requirement for serial numbers on bikes though insurance companies sometimes require it. You should probably go with your gut feeling when going this route, I think legal sales are the norm there though. You can do two things to improve your odds of staying on the right side of the law:

Check other ads on marktplaats from the same seller, check how long they have been a user on marktplaats longtime users are less likely to be fraudulent.
Dutch police has a tool to find "suspect" sellers. Fill in the sellers' username and/or e-mail address there to check if "reports" have been filed about that user (bikes are in the category "overig").

As to your final question: I think the dutch market for secondhand bikes is very liquid and very large. My gut feeling tells me secondhand bikes will be better value in the Netherlands but I never tried buying a secondhand bike in Belgium.


Can I use 26 1 3/8 tire to replace a 27 1 1/4?

No.  Bicycle tire sizes are a dogs breakfast of standards. The only standard that is consistent is ISO.

According to Sheldon Brown, 27" is ISO630 and 26"  (the common sized MTB tire) is ISO 559.

ISO630 (27x1/14) are available with a search on the internet e.g. Sheldon Brown / Harris Cyclery (not a recommendation)


What hanger is compatible with Shimano Claris RD R200?

Derailleur hangers are specific to the frame, not the derailleur. Do you not have a hanger at all or is it just broken? If it's broken, then it's usually not too hard to find a matching aftermarket one from Wheels Manufacturing or derailleurhanger.com. Have you contacted the manufacturer to see if they sell it separately?


Nukeproof Pulse SRAM PG-1030, 11/26, 10-speed to 11/36t, 10-speed

Since you're staying at 10 speed (ie, 10 different gears on the rear cassette) then you don't need a new shifter on the handlebars.  That's a wise plan.  If you got an 11 speed cassette you need also a new shifter, which gets expensive.

Your rear derailleur should be okay for the width, but the problems come about trying to clear that top gear. Its hard to tell if you'll get away with 36 tooth big gear, or whether your rear mech can only cope with a 34 or 32.  My road bike takes nothing larger than a 28 tooth.

Do you have a short/medium/long cage rear derailleur?

As Batman says, you need a new 10 speed chain when you change cassettes.  Worn chains slip on new cassettes and drastically increase wear.

Another thought - if you're not pulling top gear a lot then you can forgo the 11 tooth little cog and have a 12 or even a 13 tooth small gear.


Winter grease for extreme cold temperatures

I use Agrinol 158, which works down to -50°C. It's a blue color. It is an automotive lithium-based grease and I do not think it was specifically tested for bicycle applications; however, at -37°C it does not matter really as long as it works for someone. The "NLGI 1;2" on the can refers to the NLGI consistency number  meaning it is a "soft" grease with medium viscosity. Maybe you can find an analog where you are.


QUARQ DFour installation on Shimano bike

Your Shimano SM-BB92-41B is a BB92 standard bottom bracket.

Quarq's page lists GXP, Press Fit GXP, BB30, Press Fit 30, BBright, BB386EVO, BB30A, PF30A as compatible bottom brackets.

I believe the Press Fit GXP from SRAM is a BB92 standard bottom bracket. See https://www.parktool.com/blog/repair-help/bottom-bracket-standards-1#article-section-4.

So the GXP version is the  one you want. It would be nice if Quarq provided a better compatibility guide.


The amount of room on the rear wheel hub for the sprocket cassette is limited. In order to get more sprockets into the cassette, they have to be closer together. To
accommodate this chains have to be made narrower.

The internal width (the width of the rollers between the inner plates) is the same for different speed chains - 3⁄32" (2.4 mm). The external width is less for higher speed chains.

It's my understanding that using a 1-speed higher chain is generally workable, but 2-speeds higher will definitely cause shifting problems.

The spacing of chainrings on the cranks also has to be narrower for higher speed chains.  I believe there is the possibility for a too-narrow chain to drop in between the chainrings if used with lower speed cranksets.


Will a 3x10 or 3x9 front derailleur work on a 6/7 speed chain?

Generally yes, the front mech can work acceptably with other sizes of chain.
Since you will have a thicker chain than expected, the front derailleur cage may need to be widened a little to reduce chain rub.
The actuation ratio is between your shifter and the chainrings, so a friction shifter will work perfectly, and an indexed shifter should be acceptable.  If you're mixing shifter/chainrings then things could get odd but that's more likely above 10speed.  Below 10 speed, the chainring spacing generally was the same.
Remember the front shifter is more of a "brute force" mechanism having to move the chain under tension, compared to the rear shifter whose chain is mostly slack.  So the front shifter has to deal with higher pressures and tensions.

I have an old MTB that was 15 speed, (3x5) which now has a 9 speed rear cassette/derailleur/chain.  The front mech is still the original triple, on the original chainrings.  All I had to do was close the cage a bit to improve shifting.  I do use friction shifter on the left hand which makes trim very flexible.


How do I adjust the Marzocchi Dirt Jumper 3 (mtb fork)?

Sorry to say, but those forks do not have much (if anything) you could adjust.

The dials your are seeing are usually associated with more 'base model' coil forks and you would use them to adjust the preload (SAG).

You would adjust the preload for forks to match the rider weight against the suggested preload value. XC preload is typically 15-20%. DH is more. Preload is the initial value by which the forks are depressed in a standing state. Think of it as the bit that extends when the wheel lifts off the ground (in short).

Anyway, regarding your forks. If those are indeed Marzocchi Dirt Jumper 3's, you would find this user manual much more useful.

If those dials are still working (they typically seize up or break off on the inside) you can expect them to tighten the coil when turned in the '+' direction. However, experience have tough me that the difference in feel is negligible and in most cases those knobs are actually just for looks. You often find them on budget friendly bikes and often the dials have popped off.


Mounting light on handlebar with bag installed

As Chris H notes, the clerk was wrong. And he suggests a good suggestion to raise the light above the bag. However, you can also mount the light below the bag as well. Operating on the same principle as fog lights on cars, low mounted lights can do a better job of showing some road hazards. They are also much less likely to blind drivers and pedestrians (StVZO-compliant handlebar lights are still sadly rare).

There are lights that will mount on the crown of the front wheel fork (where the bolt for caliper brakes and mudguards attaches), but those might still hit the bottom of the bag -- although the Ortlieb bag shown in Christian Lundvig's photo is quite small and thus compatible with fork crown mount lights.

Here's a google image search for "bicycle lights fork mount". In addition to the fork crown lights, there are also front fork adapters that let you mount handlebar lights on one of the legs of the front fork.

Here's a blown up image of the top left two -- a fork-mount adapter and a light mounted on said adapter. Note that this placement is just about where ye' olde friction dynamo lights used to be mounted.

Another option is of course a helmet light:


Calluses on palms/Pressure on hands - what to do?

Use a tighter glove that can't slide against your palm. Use the hoods more than the bar tops. A bicycle fitting or perhaps just a stem with some rise could help reduce pressure on hands.


Can a fixed gear sprocket be changed without tools?

For the lockring a hammer and screwdriver works sometimes, but you end up damaging everything involved except the hammer, sometimes to the point that you can't get the lockring tool to work after the fact.
Get the lockring tool. There are semi universal ones that work ok. The type that are designed to fit specific lockrings (ie 3 slot, 4 slot) work much better. Either way they're fairly cheap. Once the lockring is off you might be able to use your bikes chain and crank in place of a chainwhip, but this is yet another place where you're better off just buying the appropriate tool. Once you have them you'll be a happier fixie rider.


The only study I know of concluded that cross chaining in relatively modern 9spd gear systems at the angles typical of bicycles had no measurable effect on the efficiency of the gearing system.

Even back in the bad old days of 52/42 with five cogs in the back, I never worried about cross chaining. Use the gears you like and replace the chain when it starts to show wear and your relatively expensive cogsets will last a very long time.

Riding with a worn chain destroys gears, not cross chaining.


bike fit calculator on competitivecyclist.com, accessing from .de

Looks like you're in Europe, and that website has chosen to reject your traffic because of that.  I've just tested from an AWS host in Frankfurt and seen the same result.
The text is

You're probably wondering why you've landed here of all places. Well, as of 25.05.2018, CompetitiveCyclist is no longer available outside the US due to GDPR regulations..."

then directs you to that .de site.
Essentially your collective nations'  GDPR requirements have been rejected, a case of "nah don't want to play with you" from competitivecyclist.com.   Upshot, you risk breaching your own nation's laws about GDPR by dodging them.
No matter how you cut it, this is a legal question about EU laws, and a technical question about web-based filtering.
This question has only minor tangential relation to bicycles or cycling, and the same fundamental question would remain if your destination website was http://llamapajama.com/   As such, this fails the "on-topic" test and will be closed.  Please don't take it personally.  You may choose to ask this on law.stackexchange.com - it is not really detailed enough to migrate as-is.


Most drivetrain setups have a 16 tooth difference between large and small rings.

Near compact: 52/36
Compact: 50/34
Sub compact: 48/32

You are trying to get a close to a super compact on a 110mm BCD and will have a chainring tooth difference of 13.

That means the rear derailleur will easily accommodate this as you have calculated.

The front derailleur will also handle the chaining size difference.

Chain length is set on the large chainring and largest cog sprocket, so you should not have to shorten the chain (assuming your chain is correctly sized to begin with). You will be within the derailleur total capacity so it will take up the extra slack.

If you do have too much slack in small ring and smallest sprocket, check the chain is sized properly.


What are these rubber rings on my brake caliper bolts for?

The bolts have a rubber ring on them, but I'm not sure what it's for. Should it be mounted together with the caliper and adapter, or is it just for holding the washers and shims in place as part of the packaging?

The rubber rings are just for holding the washers and shims in the right place and should not be installed on the bicycle.

There are many disk brake adapters. Without a description of what you have I could not find instructions specific to your situation. The pictured adapter is similar to yours (it's a SM-MA-F180P/P2) and shows no rubber rings.

Added information after the part make and model was identified:
The manual for the Tektro A12 lacks an exploded diagram or words describing the washer arrangement.
Frequently asked questions on their site does not cover this.
Their videos have a how to install a caliper part but they don't show the washer arrangement.
You can try their contact page.

Often the correct way to install something becomes clear once the part is installed. Since Shimano has a similar bolt/washer setup try it without the rubber ring first.


New Schwinn 700c (bike in a box) assembly

As stated in comments grease the pedals and seat post to prevent them from seizing.  Quill stem you might grease.

The bearings should come lubricated.

Pretty much any grease (except computer).  Bicycle grease is more for bearings but you could use it. If you are going to buy some just get general purpose grease.

Tip pedals are right and left.


Converting front crankset to a single type on a 18" Carrera Vulcan MTB bike

If you now have a triple front chainring, the best position for new a single chainring replacement would be the middle position on your current crank. It will likely to give you the best chainline for the extreme rear cassette positions (the smallest and the biggest rear cogs).

Regarding the number of teeth, it is up to you to decide, but use your existing middle ring tooth count as a starting point. E.g., if your current front rings are 42/32/24, the middle ring has 32 teeth. The new chainring should have 32 teeth or less if you often run steep uphill, or 34−36 if you focus on fast downhill. Note that if you do not feel comfortable using only your current middle front chainring (e.g. only using rear derailleur to change gears) already now, it means that the range of your present rear cassette would not be wide enough for you when you switch to a single front chainring. In this case, consider getting a wider range cassette as well. Be sure to match BCD on new and old stuff.

If you plan to get a new chainring which is marketed to prevent chain drops (often called "narrow/wide" chainrings), and/or if you have a rear derailleur with clutch, you may be fine without a chain guard (still recommended for riding rough terrain though). If you plan to get an old-school (cheaper) plain chainring meant to be used in single-speed drivetrains or one with ramps for front derailleur, you'll definitely need a chain guard.


I've looked back at some of the BMX types of my youth years and recall there weren't many Skyway wheels with as many plastic spokes, ie, 7.
This may be your best search technique if the bike is totally original to when new.
Also another rare feature is the small triangular inserted section on the underside of the frame positioned near to the Head-tube&fork tube section...


How to fix a clanking rear wheel/flywheel

From the comments above, it seems that it really is a free wheel that is making the noise.

Apparently cheap free wheels can be like that. Lubing them can help. This discussion has some extra info: http://forums.roadbikereview.com/fixed-single-speed/fix-shimano-freewheel-clunking-noises-150432.html

TL;DR version: Get some gear oil or grease gun and apply liberally.


which type of bicycle should I consider for bicycle routes

I'm going to suggest you try a cheaper used bike before committing to anything expensive.

Your only real requirement is to make sure it takes larger-sized tyres.  Off road benefits from wider tyres than on-road.

The top thing you need is a bike on which you feel comfortable.

In a year or so you can take your learnings, and decide what kind of bike will suit you best.  Your riding conditions may change as you grow fitter.

Many keen cyclists own more than one bike.  There's a running joke that all cyclists own N bikes each and they always want just one more ( ie N+1 )


How can I connect two pieces of square aluminum tubing together to make a bike trailer using n55 docs?

Here is a nice clear picture of the basic joint used in constructing things from their website.

There is a washer on both sides.
Their bill of materials calls for stainless bolts, stainless washers and stainless self-locking nuts:

B O L T S & N U T S
M6 SELFLOCKING NUTS, stainless (DIN985) - ca. 150 pieces (TWOSEATER: 200 pieces)
M8 SELFLOCKING NUTS, stainless (DIN985) - ca. 5 pieces (TWOSEATER: identical)
M8 NUTS NORMAL, stainless - ca. 5 pieces (TWOSEATER: identical)
M6 and M8 BOLTS with Hexagon head, stainless, (DIN931):
6mm x 140 mm - ca. 2 pieces (TWOSEATER: 3 pieces)
6mm x 90 mm - ca. 15 pieces (TWOSEATER: 20 pieces)
6mm x 90 mm - ca. 5 pieces in DIN 933 (full thread) (TWOSEATER: identical)
6mm x 60 mm - ca. 60 pieces (TWOSEATER: 120 pieces)
6mm x 65 mm - ca. 10 pieces (TWOSEATER: identical)
6mm x 40 mm - ca. 25 pieces (TWOSEATER: identical)

8mm x 120mm, 2 pieces (TWOSEATER: identical)
8mm x 100mm, 2 pieces (TWOSEATER: identical)
M6 WASHERS - ca. 300 pieces (TWOSEATER: 400 pieces)
M8 WASHERS - ca. 10 pieces (TWOSEATER: identical)
Concerning galvanic corrosion:

Stainless steel fasteners in aluminium plates or sheets are normally considered safe, whereas aluminium rivets or bolts holding stainless steel parts together is an unwise combination, as there is a practical risk of corrosion.
An example of the safe use of stainless steel and aluminium together is where stainless steel fasteners and hold down bolts are used to secure aluminium roadway or bridge parapet guards.
Even with no insulation between the metals, there should be little risk of corrosion.

A drill press will make life much better for a project like this.


Replacing it is the more economical option in almost all cases, especially on lower end stuff (esp. once you include labor) -- you can't source the parts for many lower end derailleurs.

On higher end parts it may be possible to send it out to a company which rebuilds derailleurs or rebuild it yourself with parts, but again, the labor and parts will likely outweigh the cost of just getting a new one (and the new one is less likely to fail; the rebuilder may make screw ups).

So, I'd almost always replace, unless I had a good reason not to (e.g. someone who insists on vintage parts and wants that vintage part repaired). Or if its a tiny deviation (which wouldn't occur if the derailleur went into the wheel; that's generally toast).


B-screw adjustment in a derailleur with a spring in the upper pivot (Shimano RD-5800)

Well, I have removed the derailleur from the hanger, put the B-screw half-way in, reattached the rear derailleur, and the noise of a maladjusted B-screw appears.

I have followed ParkTool guidelines, and now it is properly adjusted: 1/4 of turn from the cassette/upper pulley rubbing position.


The compatible part is SHIMANO RD 5700 and the part number is 5XH9812. The set come as a pair and is available at a number of places such as Chain Reaction Cycles and Wiggle.

The only thing to ensure if using generics is that they are the right chain size.


Flipflop disc brake hubs don't exist. If you were willing to ride without a rear brake, you could switch the existing wheel back and fourth by using a bolt-on track cog. I believe they give a chainline in the 41-42mm range. This plan would however be asking for trouble if you were using a hydraulic brake, since it wouldn't have its rotor in place to prevent the pistons getting pushed out.

135x12 is weird enough that I doubt you're going to find a fixed gear one stock, but supposedly Paul Components has made 135x12 singlespeed freewheel hubs, and they're the kind of company that you might be able to convince to make you one for a track cog, since the shell would probably be the same with the addition of lockring threads (unless it was too thin, in which case nevermind.)


The 40 is the inflated width in mm and the 622 is the internal diameter in mm. It's the international standard ISO-5775 for tire sizes. In brackets are the French size (700mm outer diameter x 38mm width) and the Inch size (28 outer diameter x 1 5/8 height x 1 1/2 width)

Wikipedia has a very detailed explanation of tire sizes and designations, I confirmed my answer on this page.


Yes. We try to avoid specific product recommendations here, but in this case, I know of only one option, from the Robert Axle Project. Please note that this looks like a real PITA when you need to remove the rear wheel.
There are a few racks designed to use the rear wheel's quick release as a mounting point, but I haven't seen any of these updated for through axles. If one were adventurous, one might try milling out the openings in the mounting plates or fabricating new ones. Again, inconvenient whenever you need to remove the rear wheel.


Why are crankset "sizes" often defined by the amount of cassette sprockets?

The distance between chainrings (and possibly design of ramps and pins) is determined by chain external width, which is determined by number of speeds in the rear. Too narrow (higher number of speeds) and you will have chain rub, too wide (smaller number of speeds) and you will risk jamming the chain between chainrings.

I have been riding 2x10 crankset with 9 speed chain for years without problems, but on the other hand I have also seen the chain jamming which was took quite some time to fix on the road.


Road cyclist keeps popping out of speedplay pedals

Which Speedplay pedals? The ZERO model I used quite extensively had a pair of set screws on each cleat that would set the desired amount of float through the complete pedal stroke.

The only reason you should be popping out of a Speedplay pedal is due to lateral foot rotation through your pedal stroke (which is really just an extension of knee/hip dynamics), or your cleat is not secured to your shoe correctly (angle of the cleat body to the release point of the pedal's design), or your cleats are installed on the wrong shoe...

I realize this is an old question, but hope that my information might help another with a similar situation.


How to increase speed on my hybrid bike with flat handlebars and 700X35C tyres?

Before looking to improve the bike, I'd look to improve your fitness.  I was able to average 13–14mph on my hybrid for 1–1.5hrs; at that time, I was commuting 3–5 miles each way per day and maybe a weekend ride of 15–20 miles once or twice a month.

Hybrids aren't designed for going fast but, at 11mph, there's not a huge aerodynamic difference between the more upright position on a hybrid and the lower position on a road bike.  Make sure your bike is properly maintained – a rusty chain and, especially, soft tyres sap a lot of power.

I'm assuming your bike has reasonably smooth tyres but a possible bike upgrade that hasn't been mentioned yet in other answers is narrower tyres.  I wouldn't spend any money yet but your tyres will wear out eventually and that would be something to consider then.

You might find that tracking your times on a site such as Strava helps motivate you to improve. Their app will work with your phone's GPS.


Servicing/fixing an Ultegra bar end shifter

There are pawls inside that allow for the clicking of one gear to the next.  After years of service it is quite common for those little pawls to shear from their body and become lodged in between the shift space of two gears.

Even if you free the pawl the shifter will only work in friction mode as the pall will no longer be there to click anymore.

8-speed ultegra should be able to found readily and cheaply.


What's the lowest safe cadence on a climb?

Mountain bikers regularly run these low cadences for very short periods, often at much higher power output. The issue with causing damage to knees is more about the duration of the climb and how strong your stabiliser muscles are. (Too much time mushing causes chronic overuse problems, while weak stabiliser muscles can allow injury to happen), however they also have much lower gearing for sustained steep climbs.

If this is one or two short (2-5 minute) pushes over a longer ride, I would not worry about it, but be very careful about technique. If it's a couple of 15 minute periods over an hour long ride, I would be starting to look at options before problems start.

Options to consider would be changing the route or going to lower gearing – If this is a regular route, putting a triple on the front (with a 24), would get your cadence up to about 50-60, which is ideal.

If these are not an option, getting off and walking is not a bad thing. Don't let you ego get in the way of doing the sensible thing. You're already down to about 5-6km/h, walking won't be much slower, and as it uses different muscles than riding you are resting you riding muscles.

Also be aware that if you are lowering cadence preserve aerobic endurance, you are putting less force on your knees than if you increased cadence - so without changing the bike set-up you cannot fix the problem. The mantra of high cadence presumes you can go down to a lower gear and hence reduce the force on you knees.


How should I angle my foot throughout a pedal stroke?

For most people the advice goes that you keep your foot as flat as possible. There are some riders that ride toes down (even some famous ones in the Tour) but they've had a coach determine that in their specific case there is benefit to riding toes down.

It's unlikely that you can keep your foot entirely level as it comes over the top of your pedal stroke but it should be level through the power stroke and around the bottom as you pull back on the pedal to spin.

As a response to one of the other posters, be very careful about ankling. While it is touted as a great thing many coaches feel that it does nothing and is an old wives tale. Some even feel it's harmful to you. I've attached some links for futher reading on the subject.

http://www.sheldonbrown.com/gloss_an-z.html#ankling
http://www.sheldonbrown.com/brandt/ankling.html
http://www.pezcyclingnews.com/?pg=fullstory&id=4812
http://www.roberts-1.com/b/pt/ankling/discuss/index.htm (good links in post)
http://triandrunsports.com/triforum/index.php?topic=2362.0
http://www.bicycling.com/training-nutrition/training-fitness/perfect-pedal-stroke

From the reading above, and other articles on the subject, I'm inclined to recommend against it. At the very least talk to a medical professional who can look at your pedaling technique and biomechanics and advise properly.


Converting a 3x10 to 1x10 with QR dropouts (NOT Thru axle)

You should have no issues from a frame stand point. Just make sure you keep a good chain line and you're good to go!

There are lots of 1x10 QR bikes out there. And with the popularity of the 1x10 these days your options will be abundant. Also you will want to look into Narrow/wide chainrings for the front if you haven't already. With a good one a chain guide is not necessary unless you're doing downhill stuff.


building a cargo trike (bakfiets): steel thickness

I suggest starting with a prototype made out of square tube and old bikes, especially if this is your first framebuilding project. Square tubing is a bit easier to work with (you spend less time mitring tubes) and the goal for the prototype is that it should be easy to build. Take shortcuts, in other words. Get something you can ride, then ride it. When things break, fix them.

As far as wall thickness, I'd buy whatever is cheapest. Weight for the prototype is not critical. For a final build in chrome-moly steel the thickness will depend on tubing size and how much stress it's under. You can buy plain gauge cold drawn 4130 steel tube in a range of sizes and wall thicknesses, usually by the metre. Which ones you want will depend on the detailed design.

Groups like Atomic Zombie and a lot of HPV and velomobile enthusiasts spend a lot of time just working this way, because it's cheap so you can afford to build things just for fun.

This site shows a steel prototype long john bike built and ridden, then eventually CroMo final bike built. There's some description of the design process and you can see the idea progress from welding random bits onto a steel chassis rail through to riding the finished bike.

One note of caution: you will need to tilt the pivot axle back from vertical to get more stability, but that design is inherently unstable.


What is the optimal way to draft in a group of two cyclists?

Do you both have a speedo on your bike's handlebars for reading the current velocity, (ie speedometers/head units/bike computers/) ?   It can be very hard to ride on feel, so one of the better ways to pace a group is to pick a target speed that is not flat-out, and the lead should aim for that speed.
When the leader feels its time to rotate, then you gently swap places.  The new lead should work to maintain the nominated speed, and not blast away from the now-tired other rider.
How long apart is this?  It depends on how long each person can maintain the nominated speed while on the front, and how long you each need on the back to recover for your next pull.
If you find you're holding that speed for multiple minutes and not getting tired, then perhaps you want to raise the target a couple of km/h.  Or you might be advantaged by a slight descent or a good tailwind.
Likewise if you're not getting enough shelter on the back before its your turn again, then perhaps the target speed was too high for this day, and knocking it back by 2~3 km/h would help.  Some-days you just don't go as fast, its okay.
If the group were bigger, you'd have up to about 6 riders in a single paceline, where the front one gets tired and then peels off, drifting back down the line and leaving a fresh new face to take the wind.  Tired rider has to kick it up again to hook onto the back end, but there will get a good wind saving.
Your two-person paceline is a bit too short for a casual drift back and recovery, but still its up to the leader to make a decision when to peel off and drop back.
Aside - more than about 6 riders and you have enough for a nice double-paceline, where the rider drifting back isn't just on their own, they're in a second line which slowly drops back and then across into the forward line.   Imagine a paternoster lift slowly revolving around.


Sounds like the thread of your skewer and/or the end nut is stripped ... as an emergency measure you could try inserting a slotted washer (see below) under the nut so that the QR can be tightened again, but for a proper repair, you'll need to get a replacement skewer.


Either the seller meant clipped pedal-as in you could bolt toe clips to it-or he didn't know what he was talking about. Those are not clipless pedals. They are VP road pedals that have an integrated toeclip:


Getting back on bike after wrist fracture

All but the most gentle rides on smooth surfaces can put quite a lot of stress on your wrists. Listen to your doctors on how long you should rest it because in general there's still healing to be done when the cast comes off. Not only is the bone still fragile but the muscles will be very weak. I was a teenager when I broke my wrist so timings may be different, but the length of recovery after the cast was removed was equal to the length of time it was on.

Do any physio exercises you're given, which will help you retain strength and movement. Then start in benign conditions - good roads when they're quiet - until your bike handling is back to normal.  When you first get back on, you really don't want to fall off, and wrist-jarring potholes should be avoided (you may not have the grip strength to maintain control, in addition to avoiding the shock). This is likely to be worse on a road bike than on flat bars. Everyone is different and everyone's injuries are different, but if you plan on a cautious approach and take advice from the medical professionals you shouldn't go wrong.


The 50 tooth chainring is a standard 5 bolt, 130 BCD chainring. There are other options available that will fit, but most 130 BCD will have 53 teeth, so you may have to hunt around for a bit to find a 50 tooth that you like.


It is rare for a bike bearing to suddenly seize.  Even a bearing "run dry" or exposed to saltwater or whatever will generally just get rough and squeaky.

In order to seize you generally have one of two things:

(Rare) A fragment of something -- sand, a sliver of metal, etc -- gets in between the balls in the bearing, causing them to lock.
(Common) The failure to properly fasten a lock nut or other fastener results in one of the bearing cones being "screwed" more and more tightly into the bearing, eventually making the bearing too tight to turn.

The good news is that the above second case rarely results in "fatal" damage (though it may have the effect of adding a few thousand miles to bearing wear).  So long as the situation is corrected and the bearing not "forced" to ride a considerable distance the damage is usually minor.


Schwalbe Marathon Plus vs Continental Gator Hardshell

There are reviews of both tires on bicyclerollingresistance.com: https://www.bicyclerollingresistance.com/tour-reviews/schwalbe-marathon-plus-2015 and https://www.bicyclerollingresistance.com/road-bike-reviews/continental-gator-hardshell
The Continental Gator Hardshell is considered a road bike tire, albeit a very puncture resistant one. The Schwalbe Marathon Plus is a touring tire. It’s heavier, available in wider versions, more puncture resistant and has a bit of tread.
If you need/want more than 32mm width you are out of luck with the Hardshell.
Otherwise it pretty much boils down to personal preference. Both are high quality tires with their own strengths and weaknesses. Personally I can live with patching a tube every month or so. At the same time I like to go fast/far and light. The Gator Hardshell is pretty much the heaviest, slowest tire I would even consider using. The Schwalbe Marathon plus is way too heavy and slow for me.
I’m currently using Continental GP 4 Seasons on my travel cyclocross. In the city I have about 2 or 3 punctures per year (2*6km commute). I can live with that.
If you need/want all the puncture resistance you can get there is no way around the Marathon Plus.


Could be a number of things:

Saddle/cleat/handle bar misalignment
bad form on her right side, not spinning circles, etc

Have you ridden with her and checked out her form? Is she favoring one side over the other?


How do I reduce the risk of pinch flat punctures while riding up stairs on my hardtail?

I used to get snakebites like crazy doing urban riding, even running really high pressures. I'm a big guy. What finally helped was running higher volume tires and wider. See if you can fit a wider tire in your frame, and look at getting some wider rims.

Increasing the volume of air adds more cushioning. As Batman mentioned, going tubeless also helps, since the tube displaces some of the volume between the rim and the tire.

If you're sticking with tubes, get some DH tubes. Normal tubes are around 1mm or less, DH are often around 1.5mm. They will weigh more, but might hold up better.


Looking to upgrade Sora 9-speed to Tiagra 10-speed 52/36t

Shimano's compatibility documentation says there is no compatibility between components of groupsets of different 'speeds'. E.g., there is no compatibility between 3x9 or 2x9 Sora and 3x10 or 2x10 Tiagra. The specific reason a '10 speed' front crank is not compatible with 9 speed group is that chains get progressively narrower as the number of rear speeds goes up and the spacing between sprockets decreases. The chainring spacing on the crank is optimized for the chain width.

That said, the concensus on this site seems to be that you can get away with a 1 speed difference in the crank.

Rear shifters and derailleur do not need to be changed. You do of course need a double front shifter and derailleur, the triple front shifter and derailleur you have now won't work.


While on a ride, realised rear disc rotor was contaminated, what could I have done?

Oil and contaminants from the road will float to the top of these puddles and get on the rotors.

Unfortunately once rotors are contaminated, it is EXTREMELY difficult to decontaminate them due to the porous nature of the steel they use for the discs. When you throw fresh pads on, the rotor can contaminate the pads again.

As far as brake pad decontamination, there is hope. What we do here is

Heat the pad up with a blow-torch to expand the pad material
Spray a degreaser on the pad until it stops evaporating instantly
Sand the pad with 120 grit sandpaper until you see new pad material
Clean the pad off by hitting it with the blow-torch or isoprop-alcohol
Reinstall

As far as what could be done on the side of the road, you can try tightening the barrel adjuster for your brake until you can get some form of grip or wiping the contaminants off with the inside of your jersey (That's about it).

If you suddenly lose braking power to both wheels, you can try what BMX riders do and stick the heel of your shoe between the top of your rear tire and your frame.


How do I identify an SR SunTour fork exact model?

The fork should have a serial number. Not obvious and a little small and faint, something like tb0111xxxx. Mine was located on the lower assembly.

Go to https://www.srsuntour-cycling.com/service/ enter the number and it should come back with model type and year of manufacture. From that you should be able to find the exploded view pdf.


My hydraulic disk brake pads are rubbing too hard on the rotor after taking the wheel off

The wheel might just be inserted slightly differently than it was before. That happens especially with quick release skewers. With thru axles the wheel insertion is more consistent.
Try to open the wheel, wiggle it a bit and close it again and see of the position changes. You might get it aligned well.
If it does not help, you may need to re-align your brake calipers.


MTB Sizing. Saddle at the very bottom to reach pedals perfectly. Go one size smaller?

If you have to put the saddle all the way down, the frame is too small large. You need to have a comfortable clearance between the top tube and your crotch when your feet are flat on the ground - especially on an off-road bike, since you'll often have to dismount in a hurry. There are other aspects to getting a proper fit, but this is something you can't get around.

Also, if you're on the short end of things, I wouldn't recommend a 29er. They do make them in small sizes, but in order to get a smaller rider into a reasonable riding position between those two big wheels, they have to make some compromises with the geometry. You'd be better off with 26" or 27.5" wheels.


So, chains aren't very different from tires in the sense that, they have to be replaced regularly, especially when you are commuting regularly. During summer and fall when I commute and race the most it's not unusual for me to replace my chain every other month. Chains get worn out, they stretch, they start to skip and behave poorly. If you haven't replaced that chain in two years, I'll bet my hat that it's falling off because it needs a replacement.

A new axle couldn't hurt either if you're axle is looking worn and starting to slip. You might have to trust the word of the repairman that pointed out the worn axle.


How can I make my bike (and myself) visible at night?

The obvious few things are:

Front light
Red rear tail light
Spare batteries for said lights
Spoke lights/reflectors for improved side visibility
Bright clothing, ideally cycling clothing with reflective strips on them.


Can I put a lower geared cassette on my bike?

Changing to 10 speed gets real expensive real quick, because you need new chain, cassette, shifter at a minimum.

32 tooth is 4 more than 28, so its a ~14.3% increase.  That's quite a lot - you will need extra chain links, and your rear derailleur will need adjusting and may not work with the extra teeth. It's hard to be sure without trying it.

Your other possible change is to shrink the smallest of your front chainrings.  This may mean slower changes between rings, or the FD may not have enough capacity.  You'll also need a medium or long cage rear derailleur to help take up the difference in chain length.

Final option is to grin and bear it.   Climbs up hills aren't fun.  They're supposed to be a workout.


When using the front brake, should I always move my weight to the back or is just bracing with arms is sufficient?

What is the fastest possible way for you to stop?

For me, it's pulling hard on the front brake, with my rear end well behind the seat. Ideally my rear wheel will be a couple inches off the ground the whole time. Actually achieving this is virtually impossible, but it should be the goal.

The braking technique you should use is a "light" version of whatever can haul you to a stop the quickest. Every time you come to a stoplight, or are reducing speed on a descent, use your front brake and push your rear end a little further back (or whatever technique works best for you). You don't have to brake hard. Just connect those motions in your mind by doing it every time.

The benefit of this is that when you suddenly have to do an emergency stop, you will instinctively do the best possible thing.

So to answer your question, yes, you should shift your weight back when you brake (along with bracing your arms, of course). Because if you don't, you will fail to do so in an emergency stop, when it really matters.

I completely disagree with Jobst Brandt's theory. Bracing your arms against hard braking is of course necessary, but it's completely instinctive, and therefore not a problem. What's not instinctive is 1. using your front brake, and 2. shifting your weight back. Your goal should be to make those instinctive too.

On top of this, you could further hedge against going OTB by practice stoppies (lifting the rear wheel under hard braking). If you do this, you will be much more in control during emergency stops.


Most aluminum frames have a replaceable derailleur hanger, which typically is part of the dropout itself as you can kind of see in this image:

Without it, the dropout is indeed too thin and your spacing is messed up, not to mention that the strength of the dropout is decreased. You need to identify the correct replacement hanger and get it fixed.

Also, I don't know what IGH you're using, but it will most likely require some sort of chain tensioner as well, and without sliding dropouts or an Eccentric Bottom Bracket, you're probably going to need a spring-based chain tensioner that will bolt on to the derailleur hanger:


How to properly adjust rim brakes for a touring bike?

Touring bikes, as you said, carry way more weight.  Beacuse of this additional weight they are prone to brake squeal and you need to pay closer attention to your wheels for loose spokes and out of alignment rims.
Make sure you have good spoke tension that is even all around the wheel and that the wheel is true.
The only major difference in brake setup from any other brake setup is just to nose in your pads more so than you would usually for an unloaded bike if it's needed.  It all depends on how flexible the brake mounts/arms are on your bike.
My Surly Long Haul Trucker doesn't need any nose in when unloaded but when I have an addition of a trailer and fully loaded touring bags the brakes howl when going down hill so I nose them in and the howl goes away.


In city traffic, is sitting more upright safer than more aero positions?

Being seen - the higher you are, the more likely you will be seen over a roof top. Clearly some cars are too high or too low for it to make a difference, but the odd car is at a height the difference might be significant.

Seeing - in an aero position, its harder to see as much as in an upright. It can be done by actively looking around, but its harder - you have to force yourself to do it.

Speed/efficeny - when I go into the aero position, its because I want to go faster or ride more efficiently. My concentration moves towards my riding technique than observing the road. However, it is entirely possible to sit upright and not concentrate on the road (e.g. Focus on music, sending text messages, last nights hot date....etc), so I believe upright is safer with the proviso you are concentrating the same amount on riding.

Manoeuvrability - when on aeros your ability to change speed and directions is restricted. If aero position did not compromise agility, XC MTBers would have drop bars.

So overall, I would suggest that Aero position is less safe than upright. Quantifying how much difference it made would be harder...


Which rear wheel axle does my “Citizen Gotham 7” folding bike use?

Citizens' web site photos show a standard quick release on the Citizen 7. The three speed internally geared models use a bolt on axle.


What are the benefits of cycling gloves?

All sorts of reasons:

Less damage to your hands when you fall off.
Vibration dampening.
Somewhere to wipe snot/sweat.

In practice, I use them when I am touring (long distances in the saddle - so reason 2 above), and when I am mountain-cycling competitively (reasons 1 and 3), but don't wear them when I am on my daily commute.


How does the geometry of cross bikes affect on-road handling?

A lot of people commute on cross bikes just fine (and even prefer them to conventional road bikes). He's full of it - the amount you'd need to forget to have issues is roughly being confused enough to think you're an onion (and if you're this confused, well, you're screwed anyway!), especially at commuting speeds. There are different bicycles for different purposes - for example, you're not going to take a touring bike like the Trek 520 and compare it to a racy road bike like the Specialized Allez. You probably wouldn't want to enter a road race with a cross bike, but commuting is a fine purpose for a lot of them.

There are 2 sorts of cross bikes - ones meant for racing , and ones meant for regular use (e.g. Trek Crossrip). These aren't necessarily disjoint (e.g. Kona Jake the Snake is used for both, to some extent), but you can tell roughly what they are for by looking at the components spec'd (example description for the Trek crossrip).

Obviously, you want slick tires for your commuter (if you're on the road) since the slightly knobby cross tires that come with them increase noise and can lower cornering speeds (For example, cornering quickly with a mountain bike on knobby tires does lead to washouts sometimes due to the knobs squirming). But things like the Kenda Small Block Eight are fine for commuting.

Typically, cross bikes have higher bottom brackets, larger tire clearances, cantilever/disc brakes, longer wheelbases , cables routed so that you can shoulder the bike easily and more relaxed geometries than road racers. This serves to give more shock absorbance and stability for the bike. The more commuter oriented variants also have easy fender mounting, rack mounts, etc.

I think the other parts of your question are answered in your related questions and the Wikipedia article.

Not really an answer to the question: Since rain, snow and grit do tend to damage drivetrain, you may just want to use an old cheap rigid mountain bike (e.g. 80s-90s Specialized Hardrock/Rockhopper, etc.). Great tire clearance, very stable, cheap to replace parts on, discrete (so they don't attract attention in the bike rack), etc.


Rule of thumb: how far before changing my chain to prevent cassette wear

Distance depends on how you look after the bike and what your local conditions are. Buy a chain wear gauge (plenty of other brands available) and replace the chain when it's stretched by 0.5%.


Can the tire type and profile significantly affect balance?

I did the exact same thing a long time ago. I wonder what width tyres you used?

Basically, I had a touring bike which I used for "rough" touring, and used the 38c version of this tyre.

It was fine at lower pressures in rough roads.

I then bought a set of 25c versions for a winter road bike. Horrible! These, tyres are not designed for smooth roads and high pressures. If someone doesn't understand this problem, basically, the tyre has no smooth corning edge. None.

Just replace the tyre for something more friendly.

We can recommend tyres for specific scenarios, but you haven't mentioned the type of riding or your preferance in setup.


Website for getting bike-specific touchup paints?

Gunnar bikes have a selection of touch up paint for classic bikes.

They also have great information on how to use it, and what results can be realistically expected. :)

http://gunnarbikes.com/site/order/touchup/

ColorRite also has a wide range of paint touch up pens available.

http://www.colorrite.com/product/touchup-pen-primer-1071.cfm


Gates Carbon drive on a Trek FX-S5 (Commuter)

No. Installing the belt requires a frame with chainstay or dropout that can be split so that the belt can be installed.

For avoiding dirtying your clothes, there are solutions like chain guards, reflector straps or plain old rolling up your pants or stuffing them into socks.


Brakes feel like they are not even there on my used road bike. How can I fix it?

It is quite possible the brake rubber is old. Or the rims may have an oily residue on them. As the pads age they become hard and dry. The result is long stopping distances and brake fade. You can try to use a file on the pad brake surface to remove the driest rubber. Avoid sandpaper as the grit can get lodged in the rubber and damage the rim. The results don't typically last for long. Replacement pads are inexpensive and easy to install.


The best way to improve at riding is to ride -- but many people do have limitations on their time that make it difficult to ride as much during the week as they would like.

At one end of the spectrum, there is some amount of almost all fitness-building activity that is transferable to cycling fitness. Cycling is mostly an aerobic sport, so vigorously climbing stairs or vigorous lunch walks can help. Parking or getting off the bus a few blocks away from work and then walking vigorously the rest of the way can help your overall aerobic fitness.

At the other end of the spectrum, you may want to investigate purchasing (or borrowing) a magnetic or fluid trainer on which you can place your bike so you can train at home. Many people who live in cold climates who do not wish to ride outdoors or after dark in winter either train at home or in gymnasiums to good effect, and are ready to ride on the roads when spring arrives. There are training plans and software you can purchase to guide you in indoor training.


There could be some play in the axles. Lift the wheel and try to wiggle. Another explanation might be a 'soft' fork. Also check the tightening of the quick releases, a quarter turn of the nut might bring some change.


1970's Gitane please help identify the model

Does anyone know the model of this bike? Where do I look on the bike to find out?

There are catalogs for Gitane but it does not appear to be one catalog for each year.

Velo Pages 1970 - 1974 (Did they only have one catalog for four years? Seems unlikely but I can't find any other U.S. catalogs)
Gitane USA

From what I can see it's about a 1970 Gran Sport in sport orange. Your bike has a different quick release on the front than the rear. From what I'm seeing in the catalogs the rear is original and the front is off some other bike.
In 1970 they had Mafac brakes like yours has. Sometime after 1970 they went to Weinmann.

Other Information on the Gran Sport

Gitane USA

  The “Grand Sport DeLuxe” came in both men’s and women’s models. An entry level bicycle, they were used mainly for commuting and were extremely popular with students due to their affordability. The name was used by Gitane throughout the 1970's, but was not used in the 1980's for reasons unknown.

  Grand Sport DeLuxe’s can be identified by their stamped dropouts and fake chrome fork crown. They also include kick stand mounts, which did not come with Interclubs or any of the other higher-end Gitane bicycles. Because of their popularity, they are the most readily available of all Gitane models today and can be found regular on internet auction sites.

Classic Rendesvous

  The Interclub and Gran Sport DeLuxe were the bottom level Gitanes offered during the early 1970s, and don’t warrant much space here or in your collection. They do, however, make for great “city bike” converts. Stamped steel dropouts and “chromoly” tubing, they came with extremely heavy Stronglight steel cranksets and usually with Simplex derailleurs and Mafac Racer brakes. With a similar look to the Super Corsa and TdF, they can still look good, even if they weren’t the fastest bikes on the road!


What you need is a valve core (provided the stem is threaded to take a removable valve core) [The question is, what happened to the original one?]

The cheapest option and easiest option is to just buy a new tube.


Sram Eagle NX Rear Derailleur not reacting to cable tension

If you've replaced the cabling and you see it slackening off with no derailleur response, there must be some added resistance in the movement of the derailleur itself.
I suspect it is simply the pivots of the derailleur which need some lubrication. Either a spray of teflon lube on each pivot point or a drop of oil. Then, if you have the wheel off the ground, you can move the derailleur up and down the cassette while spinning the pedals, to exercise the pivots and free them up. Just mind your fingers.
Double check the guide pulley is far enough away from the cogs, something like 13mm from the largest cog for Eagle, so a decent gap.
I can't think what else would resist the return force of the derailleur spring, except a lack of spring tension... if you handle the mech and it still has finger-crushing spring tension then all good, but check the spring for any defects.


What size chain for Shimano CS-M7771-10 (11-36T) cassette?

There’s no need to worry about specified width. The bottom line is that any 10 speed chain from a reputable manufacturer (Shimano, SRAM, KMC, Wipperman) will work fine with a Shimano cassette.


No EBB, vertical dropouts, and 130mm spacing in the rear. You have a few options. Here they are, from worst to best, and most likely cheapest to most expensive.

 Ghost ring. Basically, you get your chain length as close as you can then cram an old chainring in the chain inside the chainstay. Scary solution, especially if you don't run (all of your) brakes.
Magic Gear. Find a gear combination and chain length that gets the chain respectably tight. May require halflinks, and can be a PITA. If if works, it works great for a short time, then the drivetrain wears and the chain becomes loose and you have to do it all over again. Not a great permanent solution.
White Industries ENO eccentric rear hub. This is the way to go if you're willing to spend the cash. Comes in a variety of spacing, free or fixed threading. Works basically the same way an Eccentric Bottom Bracket does. Dropout bolts are offset from the axle so it allows you to adjust the distance from the bottom bracket to the rear axle. White Industries makes bombproof components as well.

My recommendation is the ENO, hands down. Don't bother with your current rear wheel. It's more trouble than it's worth.


Frames are made with specific axle to crown and fork offset (rake) numbers in mind for the geometry to be as intended. There's typically a common, mainstream set of numbers, give or take a few mm, for each genre of bike, but manufacturers can and do go outside of them.

Typical for track are offset numbers around 40mm. It's pretty common to see track forks with the smallest axle to crown numbers of any 700c forks (call it 370ish although there's differences in how people measure), correspondent to the tight clearance, but it's not universal because there's variance in the height of the crown itself, plus a bunch of SS bikes are now intended for brakes other than short reach road calipers.

If you know it's a level top tube bike and you have no other information about what axle to crown it wants but you have a protractor and a yardstick, you could model it in CAD or otherwise do the math to figure it out. If it's sloping top tube and you have no other information about it, you're somewhat shooting in the dark, although you could still put the frame in CAD, assume the headtube angle is typical for its size and genre, and use that as a reference point to get your axle to crown. Even if you're a little bit wrong in your guess, that will still result in a bike with handling that's about right. (Note that there's a whole world of debate about front end handling geometry and there's plenty of room for different preferences and theories.)

Finally with integrated/internal headset bikes there's the mostly aesthetic consideration of the smoothness transition/line between the headset and fork. (Mostly because some would argue there's an aero difference.) There are some trends there and plenty of manufacturers that do it certain ways, but no broader standards or rules.


How does the risk of a cyclist colliding with a vehicle vary with the speed difference?

As some have pointed out in the comments, the question is somewhat misleading, i.e. speed difference is always going to be greater in a head on collision, all things being equal, versus if the collision had been a rear ended collision or a t-bone, but, as @Daniel notes:

  "This is (mostly) unrelated to the probability of the collision in the
  first place"

According to The League of American Bicyclists:

  In 40 percent of the cases (628 total), the victim was struck from behind. The second-most common category was T-bone crashes, which accounted for 10 percent of fatal crashes. Head-on collisions (8 percent) and right-hook crashes, where the driver makes a right turn into a traveling straight (6 percent), were relatively less common.

Getting rear-ended is obviously the most common type of accident.  These numbers do not say the percentage of fatalities from rear-end collisions (they mention it for T-Bones).  However, if one holds to certain basic assumptions regarding the topic at hand:

Most cyclist will try to avoid a collision at all costs
A collision is prerequisite for fatality
Speed difference is always greater head-on than same direction, rider speed and vehicle speed held equal

The conclusion one can draw from this is that all things being equal, following these stats (and other sources below) one should always ride head on, because statistically, one has the least chance of collision, even if the closing speed is the greatest, which itself, would then seem not to have any correlation with risk of collision, or possibly an inverse relationship if assumption 3 is held.

Head on collisions may have a higher incidence of fatality than others, I don't know.  If someone finds data on that please share.

In summary, riding at a lower relative speed (to other vehicles) alongside traffic is more dangerous but probably less fatal, whereas riding at a higher relative speed against traffic is statistically less dangerous but may prove to be more fatal in the event of an accident.

Other relevant sources: http://www.trafficsafetycoalition.com/bike_studies


Do you need to remove the disc rotor to replace a drive side spoke?

Yes, usually you have to remove both to get the spokes through, although not every time depending on the specific hub and rotor.

It's typical that wheels that break spokes are going to keep breaking them due to build or material quality issues or both. So which is the least painful between doing it yourself 16 or 32 times versus paying for it versus buying a new wheel or paying to get it rebuilt all at once is up to you.

If the bike/wheel is within a warranty period and it's having this issue, it's an especially good thing to use the warranty for because if they're breaking when still fairly new, it really may not stop until they're all replaced. I've rebuilt or replaced many such wheels.

Replacing spokes is low to moderate difficulty, depending on how messed up the wheel is once you're getting it true, but does have a lot of steps, so shop rates for it unfortunately tend to be something like what you're encountering.


Wheel rigidity, is it noticeable and should I care about it?

For the average rider the answer to 'should I care?' is probably not.  If you are racing a lot of time trials then it's possible that it will make a difference.

Some of the primary benefits of a spoked-pneumatic wheel are traction and shock absorption. There is a trade off between increased rigidity (as well as higher air pressure) and both of those benefits.

So, a high rigidity wheel may increase energy transfer, and decrease rolling resistance. At the same time the harsher ride is going to increase fatigue, and the added vibration over anything but the smoothest surfaces will result in a decrease in traction.  Overall for the typical rider it's probably a wash.

It's largely the same story for the Aero benefits as well.  Unless you are primarily concerned about going fast in solo efforts the benefit would be minimal.


The short answer is that:

Yes a well sorted road bike can increase your speed, if it is done right;
That said, you can optimize a CX bike to be very similar in speed to a dedicated road bike; and
You need to get a number of pieces right (regardless of the bike category) to make higher speeds easier.

While a human on a bicycle is an incredibly efficient transportation machine we don't have much power to work with, so speed gains must be made through a focus on efficiency.  You can of course always become a stronger rider, but even the strongest riders are limited by a slow setup.

For context I commute 15 miles (24 km) each way to work (48 km total) with a weekly average speed of about 20 miles per hour (32 kph).  This is over mostly flat terrain (only 110 m climbing). I usually try and maintain about 21-26 mph (35-42 kph) on the flats to hit that average seed. This is on a "performance endurance" road bike.

In previous years with a more standard commuter setup and I was on average about 4-10 kph slower depending on the setup (slowest was on wide commuter tires with fenders and a very upright position). This was for a similar level of fitness and power input (measured with a power meter).

That is a gain of 14-40% from paying attention to all the little details and I must say I am enjoying my commute much more!

In terms of average speeds, it really can be a death by a thousand cuts. For a commuting setup I have listed the pieces I believe gave the biggest speed gains. No single one will be overly noticeable on its own, but add together it can translate into some considerable gains.

Setup details I believe that had a large impact include:

Panniers - like pulling sails through the wind.  I now use a small roll bag mounted to the front bars (backpack would be faster, but I don't like carrying things on my back).
Body position - Upright body postures may be more comfortable* but it increases your frontal area (i.e., how much wind you push). I have been fixing flexibility issues and have dropped my cockpit a couple inches down and extended it by an inch. This lets you present less of your chest to the wind (i.e., smaller frontal area). Width of your handle bar also impacts your frontal area. I keep the width the same as my shoulders which actually feels best on a low slung cockpit.
Tires - Puncture proof tires roll slow. I am running performance tires set up  tubeless so that I can still get some puncture resistance while going fast. This provided a really noticeable reduction in rolling resistance.
Wheels - regular box section wheels add noticeable drag at higher speeds, I went to some moderately aero wheels this year (and matched the correct tire width to the rim for least aero drag).
Clothing - anything even slightly baggy is like dragging along little speed sucking parachutes. I once again wear tighter road clothing as I used to many years ago.

  * Note: I understand that lower body positions are usually perceived to be uncomfortable, but find lower body positions fine under higher efforts and at times find higher positions uncomfortable for for harder efforts as you keep bending your upper back to get out of the wind, rather than stretching it out on a lower and longer cockpit. Optimal position really depends on the type of riding you do.

If you notice all of the optimizations I mentioned may be equally applied to a road or CX bike. So I would start there rather than necessarily a new bike (n+1 rule be damned). What type of bike is only a detail in the quest for speed!

There are also other basics (such as saddle height) that I have assumed you have already figured out (i.e., see mattnz's answer).

Finally, while not directly attributed to the bike setup other factors that can affect the ability of your body to do work:

Sleep, eating, physiology (e.g., hydration) and endocrinology (e.g., hormone imbalances).

You need to have all these in order as well to maintain high average speeds.


He is right.

1) in cycling, weight is distributed more on the rear wheel (70 rear-30front approx.). So even assume that both wheel is at the same leaning angle, the front would lose traction first (friction proportional to reaction force). This is because the front wheel has less 'grip' limit than the rear wheel.

2) When rider starts to corner/or correct the cornering, the two wheel are not exactly leaning at the same angle. The front wheel both leans and steers the bike (see Figure). In simplified model, you can think that the front wheel is the only component of your bicycle that 'correct' the centrifugal force for the turn. In order to correct the cornering, the front wheel needs to 1) counter-steer, to balance the leaning, and then 2) change the steering appropriately. The whole process means front wheel lose grip more easily (rear wheel change direction less than the front).

You can see the video from Criggie's answer that the front wheel lost grip, just after he tried to correct the 'leaning' and the 'cornering radius'.

3) front wheel also has less contact patch (due to load distribution again). This can be verified when you are on normal cycling position, the rear tyre usually being 'flattened' a little more.

Video:

Partial momentum: momentum that is being shared between the Front and Rear wheel (from rider and bike itself)

Rider momentum: when cornering, the bicycle generally yawns at an angle to the 'original' momentum (in order to turn). That is why we need to lean, in order to balance the 'original' momentum that causes torque in rolling direction.


How do I find the master link on a Mongoose Intake dirt jump bike?

There is a good chance that there isn't a master link. Many single speeds do not have one on the factory installed  chain. It requires a chain tool to press out the pin. At that point a master link can be installed or a replacement pin can be installed using the chain tool. The chain does not need to be removed to change the crank unless it is worn. If you are changing crank or chain ring sizes you will need to either shorten your existing if it is serviceable or replacing it if its worn or too short.


Cranks and chainrings are made of aluminium, which does not rust. You'll probably be fine with cleaning them and new cassette and chain. This isn't that expensive any more. From quick googling, your bike uses 7-speed cassette, which are still available.

Upgrading to modern parts would require replacing all transmission components, shifters, derailleurs and the rear wheel. This will be expensive and probably not worth the trouble.


Replace S-RAM S7 gear hub with something better

The cheapest option is probably to buy a whole new wheel off the internet. The Sturmey Archer 5 speed with drum brake is my first choice (www.sturmey-archer.com/products/hubs/cid/4/id/33) - costs about 140 pounds for the hub from SJS in the UK. The advantage of the Sturmey hub is that it's designed to work in various frame spacings so you just remove a couple of spacers and it'll work. They're rumored to be quite robust but I haven't tried the 5 speed, only the 3 and 8. But the brand is good (was UK, now Taiwan, which seems to have lifted the manufacturing consistency a bit).

If you can use a disk brake on your bike the Shimano Alfine 8 is a good option, about $US400 with a cheap brake by the look of it. (do not get a Nexus hub, they were a bit of a learning experience for Shimano). They're available with a disk brake as an option, so it comes down to what your bike frame will accept. If it's got an internal brake now it'll almost certainly accept the drum brake, but if it'll take a disk the Alfine is a slightly nicer hub.

With the Alfine you'll probably have to spread it to 135mm, as (from memory) there aren't any spare spacers you can remove. The SA with drop right in. But if your frame is steel you will almost certainly be able to just spread it the 5mm to take the slightly wider wheel. If you're not comfortable doing that a bike shop or framebuilder will be able to "cold set" (ie, bend) it for you. With aluminium or composite frames that's not an option.

(I don't have enough points to embed the third link, sorry)