What will the difference in speed be between an endurance geometry road bike and a race geometry road bike? I am looking to get a new road bike and am wondering if there will be a difference in speed between an endurance geometry bike like the Fuji Sportif or Specialized Diverge, and a race geometry bike like the Fuji Roubaix or Specialized Allez. I am looking to go as fast as possible but I also plan on going on 50+ mile rides so comfort is also a factor for me.  I also do not plan on doing many hardcore road races.
Other info: I am 140 lbs.

The main difference will be increased drag on the endurance model, as it is likely that you will have a higher handlebar position and this will increase your frontal area and in turn drag. However, if it is more comfortable in the more upright position, you may be faster as you are more efficient in putting down the power.

If you are not racing regularly, my suggestion would be the endurance model, as you will be more comfortable, and if you want the low aggressive position that can be achieved by moving the stem/spacers around on the steerer tube.


Pedals spin freely in cold conditions I recently bought a second hand Giant Upland SE and to be frank, it is my first bike with multiple gears. The bike functioned normally for the first day or two. I could use all the gears.  When the bike is stored indoors, the pedal and wheel work fine but once I take it out in the cold (anywhere from 0 to -30 degrees celsius), the pedals rotate freely and have no action on the wheel. Also I am not able use some gears on the rear wheel. Can anyone please help with an explanation and solution?

The pawls in your freehub are most likely getting stuck, causing them not to lock and transfer the force from the cassette to the wheel. In your case as the bike is new it is probably due to it being assembled with grease rather than a lighter oil, but the problem can also come with ageing. You will need to rebuild the freehub. This is not the easiest procedure and requires some specific tools (chain whip and freehub nut at least) so probably get your bike shop to do it.

The unusable gears on the back could be a number of things, rear derailleur limit screws, lack of cable tension, bent hanger/derailleur... If you are already taking it to a bike shop just ask them to fix it.

EDIT: Based on the additional information (-30 not 30  Celcius and secondhand), like others say the freehub is most likely frozen due to old grease and or water which has gotten inside the hub. Same advice still applies though, you will need to overhaul it and get new grease in there or just buy a new one.


How to choose rim strip width? After referencing How do I know which size and type of rim strip to buy?  I still couldn't use any of the answers to identify the correct width of rim tape to choose.

Velox tape comes in narrow (10mm), wide (17mm) or ATB (22mm) sizes.  What rim widths or styles are each of these sizes appropriate for or how can I determine which width is appropriate to use?

I'm not sure if the same rules apply for very large rims either. Should I just use the largest size, ATB tape (22mm), on very wide rims like velocity blunt 35 (35mm wide) and dually (45mm wide)?

You want the rim strip to just cover the flat bottom of the wheel. You just need to cover the spoke holes. If the rim strip is too wide it will climb up the sides of the wheel and potentially interfere with the tire bead seating properly.


How does one adjust the equivalent of the barrel adjuster on the XTR RD-M9000 rear derailleur? I'm used to be able to turn the barrel adjuster on a rear derailleur to be able to bring the derailleur in or out (relative to the wheel). However, it doesn't seem like this particular derailleur works like that and I'm unable to find the equivalent.

The product docs didn't help too much either: https://bike.shimano.com/en-EU/product/component/xtr-m9000/RD-M9000-SGS.html

Page 19 of the linked Dealer Manual shows the barrel is in the shifter, up on the bars.

From https://si.shimano.com/pdfs/dm/DM-RD0004-09-ENG.pdf

If yours doesn't have one, are you using a different/wrong or off-brand shifter?  You will need to fit an in-line barrel adjuster like this:


Rear seat for kids electric bike above battery I have a bicycle as in the picture. Are there any child seats that can be fixed in the rear of this bicycle?
ANy suggestion is appreciated.

In the Netherlands, where most parents cycle with their kids, kids seats are now routinely attached to the seatpost or the part of the frame where the seat post drops into.
The kid will be above the rack but much of the weight will be on the middle of the frame.
There is no contact between the seat and the rack with battery. Many e-bikes are sold with both front and rear kid seats.
I did not find any 'non commercial' pictures so far, but if you google -bobike rear kid seat-  you will find several or many of that brand (other brands are also likely to have them, but I do not know their names, I am not connected to the brand in any way, I just see them used often.)
Do not worry about the weight of the child, many Dutch ride with adults on the rear rack, with no problems. (The racks may not like it, the weight spread over the bike works.) Just keep an eye on how you handle the bike with the weight there.
And do not forget the child when you get on or off when you are used to a diamond frame, see this video fragment.


Query on bearing / race sizing I'm looking to replace the bearings in the headset on a brand new GT mountain Bike (they have disintegrated after 4 weeks).They were the caged type but exposed so I can see each of the balls in the ring (i.e. not sealed)

I know from Cane Creek site that I have ZS 44/28.6 & ZS44/30 sized headset but no clue what the relationship is to my bearing size....sorry if this is a silly question!

Can anyone please recommend where I can buy the bearings?

Ball size is ideally measured either with a caliper or, more commonly in shops, with a purpose-made tool that has a hole for each size to compare against. 5/32" is the most common size for headset bearings by far, but 1/4" and 3/16" are also around. (So it's not a silly question, and it doesn't have any relationship to the headset size per se.) There aren't any oddball in-between ball bearing sizes used on bikes, so to get the size you're safe holding an individual bearing next to a ruler and eyeballing the 5/32" or 3.97mm.
It's likely to be the most common of them, 5/32x22 (22 balls). 5/32x20 also exists so it's wise to count or compare the old alongside the new. Both are common and super cheap bike shop items.


Shimano Deore 2x10 derailleur M6025-L with 3x Alivio M4050 crank Will my Shimano Deore front derailleur M6025 2x10 work with Shimano Alivio 3x crankset?
I'm confused because my front derailleur is not 3x design.

Yes, it will work, but not optimally.
According to the bible:

"Double" front derailers will work with triples, but if the middle ring is much smaller than the big ring, they will be balky shifting up from the small to the middle chainring.

Several options:

Drop the smallest chainring. You won't need it anyway. I have done this and I'm happy with the result.
Learn proper front shifting technique and live with the poorer shifting of the double derailleur on a triple crankset.
Find a triple front derailleur.
Find a double crankset.

I used to have a very cheap bike with a double front derailleur and triple crankset. The diminished front shifting performance was not noticeable because all of the components were so poor that every shift was poor anyway, even in the rear!


Eggbeaters cleats mounting to 3-hole shoe I have crank bros. Eggbeater 2 pedals. They came with two hole cleats.  I need three hole cleats in a triangle pattern to fit my bike shoes. Is there such a thing and where can I get them.

AFAIK three hole Eggbeater cleats don't exist - but - there are adapters for road shoes. I used to use this setup.

You can see the cleat is bolted to an adapter plate from the back. The plate has the 3-bolt pattern

The U-shaped thing on the left presses on the studs on the adapter plate and protects the cleat. I took it off so you could see the bolt arrangement.

Update: now I think about it I think the metal cleat is a special one that works with the adapter plate, not a regular 2-hole cleat, so the whole thing is really a '3-hole cleat'.


what is the correct tire size for a trek 7300 multitrack? I have a trek 7300 multitrack hybrid bike. The tires and tubes are at least 7 years old and I would like to replace them. The rim does not have any sizing printed on it that I can see. The current tire is a WTB Slickasaurus which has marked (37/32) 700c and 700x37/32c. I understand the 700c is for tire diameter. What does the 37/32 represent?

Is the Slickasaurus a good tire for the bike, or would you recommend some others? I spend most of my time on paved roads, and occasionally a little gravel/dirt road.

edit: sorry you think this is a duplicate question. I did see the linked question before asking but it didn't seem to explain 3 numbers which is what I saw marked on my tire. Also I don't think the tire on the bike now is the original one it came with.

edit 2: here's how it looks on my tire

Bike Blue book has the original tires on a 2012 model as 700c x 35:
 bluebook

You could just go with any 700c x 35 tire. I've found that many local bike shops can order for a similar price as mail order and they'd be able to match your tread to the terrain and weather conditions in your area. As far as width, you might be able to go slightly wider with a 37mm (as you currently have) or 38. It all depends on your tire clearance, especially if you have fenders.

As for your particular tire, I agree the Slickasaurus have ambiguous markings. The manufacturer's website doesn't give any information so I took this screen grab off Amazon for a Slickasaurus tire that shows  "700 x 35c (35/32)".  My reading of this is that it fits on 700c rims normally designed for a 35mm tire width (that is, the wire bead is close to that of a 35mm), but because it's a slick tire, the actual tread width is closer to what a 32mm tire would have.

For your old tire, it means that it nominally fits rims designed for tires that have a wire bead profile closer to a 37mm tire's wire bead but in actuality has a tread profile closer to a 32mm profile.


Seatpost won't let me set my saddle "level" I recently changed my saddle and I've found I'm unable to get my new saddle level (as measured with spirit level).

The problem is the seatpost clamp - it has teeth on both the concave top of the shaft and the convex clamp part that fit together to prevent the saddle angle from changing. These teeth are quite large and they restrict the possible angles the saddle can be set at.

My previous saddle just happened to have an inherent angle that matched the seatpost, so I was able to set it "level" with the ground. I find with my new saddle, it is either slightly tipped forward or slightly tipped back. Neither are satisfactory - I need something in between.

Does anyone have a suggestion for fixing this (short of buying a new seatpost)?

Unfortunately, this is a common issue with more basic seat posts.

There are 2 options:

Use sandpaper or a Dremel to remove the teeth which fix the angles of the seat post. If you make it completely smooth, then you can use grip tape like that designed for a skateboard deck to add friction without locking you in to specific angles. This approach has drawbacks. The grip tape may need to be replaced on occasion. You need to be careful not to remove too much material from the post, as it risks breaking the post in use. As you can imagine, that would be painful.
Replace the seat post with something without that limitation.

I hope that helps.


Are older road bike parts compatible with newer standards? How do older and newer bikes match up performance wise? I'm a big mountain biker and looking to get into road biking.  However, I don't want to drop $1,500 on a new or relatively new road bike without being sure I'd want to stick with it.  Anyway, I found an old 1974 men's Schwinn Varsity 10 speed road bike on Craigslist for about $100 and I'm not sure of a few things:

First, I'd like to upgrade a few parts on the bike if I do buy it, e.g.: clipless pedals, possibly a drivetrain overhaul, etc.  The only thing I'm not informed of is compatibility.

Second of all, I really have no idea how a bike this old would match up to a bike from the last 5 years or so.  I'd be riding with people from my local bike shop and I wouldn't want to have a tough time keeping up because of shortcomings in my ride.  Obviously a newer bike is better, but does the difference really matter if I'm not doing the Tour de France?

Upgrading an older bike is typically not economical.  Parts are typically not cheaper.  Parts are not as available.  That drivetrain is not compatible with a modern bike.  Bikes have gotten better.  Little faster, lighter, more comfortable, and easier to service.  You can find decent to nice newer model used bikes for $400.  Find someone that bought an $800 bike thinking they were going to get healthy, did not ride it, and is selling it for $400.  It happens and that is your best value.


Is a long, high angle stem safe to use with a carbon steerer? I purchased a hardly used road bike someone else had built up for a deal a few weeks ago, and am a bit disappointed with the fit - it's fine for rides less than a couple hours, but too aggressive for anything longer, for my tastes. In particular, the problem is that my saddle is about an inch and a half above my handlebars, even after inverting the 6 degree, 75mm stem that is installed currently.

So I purchased a 40 degree, 120mm stem to try and get the handlebars as high up as possible. However, I'm now a bit worried that having the handlebars so far from the steerer tube, which is carbon, will offer too much leverage and may cause the steerer to catastrophically fail when, for example, I ride out of the saddle.

Does this seem safe? Are there any guidelines for how long and steep a stem can be for safe use with a carbon steerer?

For what it's worth, I'm about 145 lbs and the fork is an Enve Road Fork 2.0.

Within "normal" standards of long and high angle, yes it is safe.

While there are some stems which use clamping styles which are not carbon safe, or other restrictions, these are usually clearly stated.

No restrictions are based on length or angle of the stem, that I am aware of.  I have been a certified professional bicycle mechanic for 20 years, so I would think I'd have seen it by now, if it were an issue. :)


Why are 10 speed chains so expensive? I've noticed that 10-speed chains cost 2.5 times as much as their 9 speed counterparts. Is this just because there isn't much demand for these, so the manufacturers can justify the ridiculous expense?

Is there a cheaper option?

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.


When should a wheel be replaced? I an not talking about upgrading. How do you know when to buy new wheels because the other ones have worn out? How do you tell a wheel is worn out? I can always true a wheel back to true. And nothing is dented, but the maintenance is getting a little more than it should be.

At some point the spokes become too fatigued and start snapping.

At some point, with rim brakes, the rim wears through until it's no longer stable.

At some point the bearing races in the hub become too worn.

Of these, only the third reasonably demands that the wheel be replaced -- wheels with worn spokes can be relaced, and rims can be replaced without relacing.  But in some cases, especially if more than one of the above problems is looming, it may be more cost-effective to replace the wheel rather than repair it.

And, of course, there's always the case of some sort of actual damage to the wheel -- ripped spoke holes in the flange, bent flange, "taco-ed" wheel where both spokes and rim will need replacing, etc.


Help in figuring out a replacement rear wheel for Huffy Savannah 27" I have a Huffy Savannah 27" bike that I bought about 6 years ago and need to find a replacement rear wheel.  The bearings went bad, but the rest of the bike is almost brand new.  The tire is a 700c x 38.  How can I find suitable replacement?  I don't care about brand, only that it will work with the tire.

New ball bearings will cost less than a new wheel - the order of $5 for a bag.   It may be that your bearings are okay just mal-adjusted so there may be no cost for parts.

You'll need a cone spanner and a conventional spanner, some grease, and cleaning gear (rags/ solvent like petrol or whatever)

Since its the rear wheel, you'll need the special tool to remove your cassette/freewheel as well.  Even buying one of these its still cheaper than replacing the wheel.

This is a good start:

Another option is to find a bike coop in your city and ask for some assistance.  Wheel bearings are straightforward fixes.

If you don't feel that you can do this, a bike shop can change your bearings for half the cost of a new wheel.


Can I change my hub so I can put disc brakes on the bike So I have this 2007 Janis XC bike and I’m turning it into a trail bike on a budget. I wanted to know if I could change the hub on the wheel instead of buying a new wheel set so I can install some disc brakes?
The bike frame already has I.S mounts for disc brakes.

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


Bike Identification needed, townie bike I have a bike I purchased from a rental company about 8 years ago. It would have been three years old then, so that makes it a 2008 year bike. I could have sworn it was made by a medium end bike company, like Trek or Specialized, but I can't remember. I've also covered the bike in bumper stickers so I can't see the original graphics. I do have a logo from the front though.

It's a 24 speed but I really doubt that that matters. Here's a side view, but it just looks like a pretty generic bike to me.

I don't think it is a duplicate because I really don't care who made it, but the bike is for sale and a potential buyer may care.

This bike was rented, and later purchased, on Cape Cod, United States.

Looks like a Gary Fisher bike to me.

If it's a 2008 then it would have to be the Mako because all the other Gary Fisher bikes in the database have a suspension front fork. It was the cheapest Gary Fisher you could buy that year.

This particular bike came with the rare and highly coveted pig accessory.


My Bike doesn't seem to fit itself I have a project bike. I made it myself from bits recycled.   It is currently a single speed, although I'm thinking of adding gears to turn it into a bit of a commuter/excercise bike.

Before I do that, I really need to sort out the fit.  It doesn't seem to fit me, or even itself very well.

Bike dimensions - 51cm seattube, 50cm top tube, chain stay 41cm.   tires are 700x32.

The problems:

The bike has a seat tube length of 51cm which seems right for me at 5'6.  When i sit on it my leg is straight at the bottom of the stroke, However there is virtually no standover room.
the bike seems pretty cramped horizontally, that is the handlebars seem too close to the seat.  in fact i'm not sure if the top tube is long enough.
The front wheel, despite being the right size to line up with the brake, seems to be way to close to the downtube, and as a result clips my toes sometimes when I'm pedaling. Does this bike even fit itself?
both wheels are pretty tight through the brake.  That's probably because of the chunky tires.

What have I done wrong? How can i get the bike to feel a bit less cramped?

The geometry of this frame looks odd. 622mm wheels are too large to fit comfortably in a 51cm frame. Usually sizes this small are made to compensate with very steep seat tube angle to let the rear wheel forward and very shallow steering angle to avoid toes clipping front wheel. This bike has been made the other way around and that is why it looks and feels strange.

With saddle as low as shown in picture, the frame is too high for you. With horizontal top tube, there should usually be about hand's width of seatpost showing. The saddle should be roughly horizontal.
Longer handlebar stem or less swept back handlebars will help.
This is a problem with all small frames with large wheels. Is the fork the original one? Some older bikes came with steep steering angles and very high fork offsets. The offset eliminates some of the problem with toe overlap but makes steering twitchy at high speeds.
32mm tires are the absolute maximum size to fit inside short reach brakes. Normally the kind of brake is used with 23mm to 25mm tires.

Edit: @Will's comment led me to the idea that this bike could have been a 650B or at least converted into one. That would reduce the standover height and allow wider tires and also explain the strange-looking angles. Smaller wheels would lower the bottom bracket, so saddle would still look too low.


'safety dot' on rims My Araya GP-710 rims have a sticker that says 'safety dot' with arrows that point to little dimples in the rim -what are they for ? Dimple not visible in pic, but are on the rim

As long as you can see the dimple, the rim is still thick enough.

When you brake, the rim gets worn. Eventually it is worn so thin that it can break. The dimples help you identify the wear so that you can replace the rim before it breaks.


Problems with a slipping seatpost I got a Cannondale Quick1 2010, with the seatpost made with aluminium carbon-wrapped.

The problem is that the seatpost tends to slide downwards, even if I squeeze a lot the snap ring; if the ground is uneven the seatpost slips completely.

Is there a way to solve this problem?

Many thanks.

Your local bike shop should be able to sell you some carbon gripping compound, for example Finish Line Fiber Grip.  Other similar brands are available!

I've no idea what the seatpost clamp is on your bike but I'm always suspicious of ones that are hand tightened.  I have 2 bikes with carbon seatposts & Ali frames, I use Salsa clamps that require an allen key & I don't experience any slippage.


Front Wheel axle (Quando) with 1/4 bearings my first post after years of using the forum.
I am a mobile mechanic and keep coming up against these Quando front hubs (sometimes unbranded) that have a standard 9mm QR axle spindle, but with larger cones (these cones fit fine in a rear hub, just not the axle) and 1/4" bearings. I cannot find replacements anywhere, does anyone know what I could search for, or what is going on here? 99% of hub servicing I do apart from OEM shimano cones etc use the "standard" but this is a wierd hybrid and it's doing my head in!!
To reiterate, I have serviced hundreds of hubs over 10 years of working so I understand the general ideas of bearing sizes. I am really looking for any specific information on this phenomenon from someone who might have come accross it before.
Thanks in advance
Dan

I've recently overhauled a Quando front axle with pitted cones. Fortunately, I do have a Quando hub with the common 3/16" and not the unusually large 1/4" ball bearings.
However, the bearings had standard sized balls at 3/16 in. I replaced them with with Shimano Y00091210 balls.
I couldn't find the exact cones as replacement. However a standard set of axle + cones did fit with only a marginal increase of distance between fork ends.
Since Quando hubs are not good at all, and usually built into low quality wheels, perhaps a complete wheel replacement would be a better offer to customers?
A 1/4" ball bearing front hub is hardly serviceable. What is more, Quando hubs need servicing very often because tolerance are awful. (My well maintained one was done for in less than 1000 km.)


Sram quick link on a Shimano chain Is it compatible to use a Sram quick link on a Shimano chain (both 11sp.)?

Sram's chains are little bit wider than Shimano's. Sram links will only work with Sram chains. KMC will work with Shimano chains.


needing new front suspension I have an old Schwinn sidewinder 2.6 mountain bike. I'm starting to get into better trails and I want to upgrade my front suspension. It has the standard 1-1/8 steering, but its a threaded shaft. Does this mean I can't upgrade to the new "smooth" style forks that are readily available?  I guess in short can I put any suspension in my bike if i change the front forks and handlebars?  I don't know much about bikes suspension and what can be messed with and what can't.
Thank you
Kyle

Given that the Schwinn sidewinder is a Walmart bike, you're best off getting a new bike. We call these BSO's or bike shaped objects.

By the time you get a basic suspension fork, you'll be spending more than the bike after installation, whereas you could easily buy a good used entry level front suspension mountain bike (say, a Specialized Hard Rock or Trek 3700 or whatever) for slightly more, which will be way more durable and better quality components.


what will happen if I change gears on a mountain bike at a standstill? Will it break? My boyfriend just bought a brand new bike and was trying to teach me to ride it, and (I, being a complete noob) when I was standing with it I messed with the gears using the handle at a standstill. Changed the rear one from 3 to 1. He then started riding it and the the plastic part that helps it shift (I think) broke. You could hear a sudden crunching when he started riding it and the whole back part just snapped and broke. I assume it was that I just moved that, but was it? And why?

The changing of gears itself is unlikely to cause any damage, you're just going to move the derailleurs back and forth until the chain prevents them moving further.  If you really forced it you might break a shift lever or something.  However, bad stuff is likely to happen if you heavily load the drivetrain while in the wrong gear.  I.e. if you change gears while standing still then forcefully push down on the pedals when getting started, since the chain isn't on the right cog.  There's a good chance then of the chain falling off or of it getting jammed somewhere, either leading to you falling off the bike, or potentially to some damage to the bike.  With regards to your missing plastic bike: I don't know exactly what it was, but if the bike still works fine I wouldn't worry about it.

Also, your boyfriend. not you, is the fool in this situation.  Changing gears while stationary isn't that crazy.  Taking the bike and cranking heavily in the wrong gear is.

If you find yourself stationary on the wrong cog you just need to lift up the rear wheel and turn the crank forward a full revolution or two: that should get it into the right gear.  With a little practice you can do this standing over the bike with your foot on the right pedal: lift the rear wheel off the ground slightly using your right hand on the saddle and push the crank with your right foot.  Handy if you find yourself in the wrong gear at some traffic lights.


Are there any light mounting products that is adjustable? Let me try to explain my situation.

We have three bikes. We probably have about 3 or 4 locations where we may leave the bike (home, work, parent's place etc.)

We don't want to be carrying a light everywhere as most times we ride in the day time, so my plan is to leave one light at each place.

We have a bunch of lights already but each light generally come with one plastic mounting thing (that thing you put on your handle bar so the light will sit on) and all the lights I have seem to have different types of mounts.

So I guess I got two problems.

1) One light only has one mount, therefore one light can only go on one bike.
2) If I want to put a different light at each place, I pretty much need to put about a couple of mounts on each of the bikes.

I guess one solution is to throw away my existing lights and just invest in 4 of the same brand of lights. But just in case, is there like adjustable mounts I can get which would fit all lights and for which I can essentially just mount on each bike and each light would fit on it?

I've also heard of Knog Frog lights which seem convenient but they look too small to be safe for me.

One option for front lights would be to replace them with torches and rubber/velcro mounts such as below, these would be interchangeable and fit pretty much anything - I have even got my iPhone on to one.

As for rear lights you may have to invest in 3 sets of the same light. alternatively in the past I have had to DIY mounts using elastic bands in emergency (not long term solution).

Otherwise consider carrying the lights with you! in the long run it's probably more sensible to have one set that you can keep track of battery wise and condition wise.


Advisable to switch from 38 mm tires to 28 mm? I have a urban/hybrid bike ( Riverside 500 that came with 38mm tires that I don't really have complaints with except some visible cracking since a year or so (which hasn't impacted feel, air retension or anything at all) But I have been thinking of replacing these 700x38 tires.
I can go with 38, 35, 32, 28 or 25 mm tires to replace these. I am speculating about going with 28mm as of yet.
I dont do any off-road stuff , I stick to road riding and commuting mostly on great highways but the occasional pot-hole riddled by-lane does come up , so fragility or sharp feedback is best avoided .
Which size is ideal in this scenario ?

Two things to take into account.
Firstly, 28mm tires lower your bottom bracket by one centimeter when compared to 38mm tires. If your bicycle was designed with 38mm tires in mind, it probably has a quite large bottom bracket drop. With 28mm tires, you can touch the ground with pedals when cornering pedaling.
Secondly, from 38mm to 28mm is quite a large change. Are you certain that 28mm tires are what you want? They require far higher pressure and the ride is less smooth.
Considering that one of the best tires, Continental Grand Prix 5000, is available as 32mm width, I would pick this width in your case. (Don't do what I do; instead, do what I say -- I use the 28mm width of GP5000 but in my opinion 32mm may be even better for people not used to narrow high pressure tires.)
The rim width may also limit your tire options. A 28mm tire requires a rim at most 622 x 19C. If the rim is 21C, you should not use 28mm tires.


Which is safer: country road vs highway? Asking the park ranger about my planned itinerary, her answer was to take, instead, a 4-lane divided highway with wide shoulder, the argument being that it would be safer than using 2-lane/little-or-no-shoulder country roads. Adding that "people drive like crazy" on country roads.

I've heard the same argument offered by a park ranger at another location.

I personally hate riding on highways, because of the noise but also because this is where the occasional narrows (e.g. bridge, overpass) appears to present more hazard potential, and based on the impression that the difference in traffic volume makes it more likely that a DUI/sleepy driver might hit me.

Anyone would be familiar with a source that would offer some indication of the probability of serious or fatal injury suffered by a cyclist as a function of the type of road?

EDIT

As much as I appreciate the sensible opinions expressed below, I couldn't find any evidence to support the impact of road type on hazard.

The closest that I found is a statistics from the UK comparing built-up vs non built-up fatalities and serious injuries for various types of vehicles. The proportion of incidents affecting cyclists vs motor vehicles driver/passengers is the same, irrespective of the road type. Same for A vs B roads.

Another way to look at this question - none of the reviews on the etiology of cycling mentioned the type of road. Mentions were made about the hazard posed by intersections (car attempting a right turn while a cyclist overtakes on the right; failure to obey stop or light) and dooring.

Sorry for not providing links to sources - I am on tour and using a phone to post/edit

This is highly dependent on where you live and the driving+riding culture in the area.

For example: In the town I live in (Midwestern US), heading south or south east on country roads is fine -- people are calm and aware for occasional cyclists. Heading northwest its a tossup between the country roads and following the highway. And heading southwest, I'd follow the highway as long as I could.

I've driven along I-40 in Arizona before, and it looked like a wonderful place to bike (esp. near Flagstaff); You could see cyclists on it. On the other hand, other highways may not be good, like I-5 in California from LA to SF (where I doubt it is even legal to bike; if I had to travel along it, I'd rather use PCH 1, depending on the destination).

You have asked two (presumably) trustworthy people, who should have a good idea of the area and suggest using the highway. I'd heed their advice. This is probably the best way to check itineraries (ask someone who knows). Systems like google maps and stuff sometimes give you shorter itineraries or whatever, but they aren't necessarily safer roads to ride on or not properly verified data.

Highways have some advantages -- regular traffic flow and usually enough room to ride on the side of the road versus narrower roads in the country. Plus, if you do get hurt on a highway, someones likely to see you. On a country road, it isn't clear. The threat of a drunk/sleepy driver on a wide highway shoulder is pretty unlikely relative to something like being hit by a car on a country road cause someone was driving recklessly and/or didn't see you. A shoulder is effectively your own bike lane (modulo the occasional broken down car), and it's ideal to use if you have one. Only downside is you have to be a little more careful with debris like glass bottles and what not in some areas.

Plus, on some country roads, you have to deal with wild animals. Less so on highways during the day.


Need a method to wrap H-bars with handlebar tape I've gotten good at wrapping drop bars, using conventional cork tape: You start at the end and work your way up, keeping the tension even and watching the overlap, and it works perfectly for me.

But the H-bars on my Bike Friday have aways been a challenge. They're smaller and more finicky to wrap, but that's just a matter of time and practice. Specifically, getting the intersections at the bar joins to wrap cleanly has always been a problem:

Over time, the tape will invariably loosen because of this.

Can anyone suggest a method for doing this that will stay for longer? Should I wrap the main bars separately from the vertical bars? Is there some special secret way to do this? Or is this just a downside to this kind of bar?

Edit: I wrapped the bars from the top of the barend down to the bottom, then getting the main handlebars. The below picture shows the problem area; note the separate piece of tape.

I'd wrap in two passes: first, from the bottom stubs to the join, just crossing over onto the ends of the main bar. Then tape this up tight, to squash it down. Secondly, I'd wrap from the tops of the bar ends around the joins and all the way up to the stem. The second pass should cover up the tape holding the first bit of wrap.

Maybe something like this (excuse terrible paint skills)?


Can I use an expanding plug rather than a star fangled nut in a steel steerer? I've got a Genesis Equilibrium 725 steel frame and fork that came with an unbranded (but said to be Prestine) headset and Genesis-branded top cap and star fangled nut.
The headset and nut aren't fitted, and I'm considering buying a Cane Creek headset to use instead of the unbranded one, but my question here is specifically about the star fangled nut:
Can I use an expanding plug instead of the star fangled nut?
I am aware that an expanding plug must be used instead of the star fangled nut in a carbon steerer (e.g. see the entry for "Star Fangled Nut" in Sheldon Brown's glossary) and I have heard that expanding bolts can be used in aluminium steerers, but what about a steel steerer?
And should I be looking for a particular type of expansion plug?

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

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


Changing a cassette and adjustments after I just changed my cassette from a 32 to a 34. All is good but on the big sprocket in the front it will not change properly on the big sprocket on the rear. On the small sprocket on the front it will shift good onto the big big sprocket on the rear. What am I missing? Adjustment or a longer chain?

If you can change to biggest sprocket on the small chainring, sounds like the chain is too short. If it's new you can add a link in (if you have the left over links), otherwise you'll need to replace and resize the chain.

You should probably also check that your rear derailleur can take a 34 tooth max cassette sprocket, and you have not exceeded the derailleur total capacity (difference in chainring tooth counts plus difference between largest and smallest sprocket tooth counts).


How should I measure my 60 second resting heart rate? My heart rate monitor has a feature that measures my drop in heart rate over a 60 second resting period.  It is suppose to just be a measure of heart fitness (the faster the drop the better your heart), but I haven't been able to come up with a consistent way to use it.  Should I start just casually pedaling? Stop pedaling? Stop the bike? Get off the bike?  The biggest drop I get is I get off the bike and sit down on a bench, but I'm not going for biggest, I'm just trying to figure out how I should measure it that would give me a result that I could compare to my other results and maybe compare to a chart of values and how good they are if such a chart exists.

The usual recommendation is to just pedal slowly and then take the measurement. If your recovery rate is 12BPM or less, you should go see a doctor. A very fit person would recover 40+BPM. Someone who engages in regular cardio exercise would probably see recovery rates of 20+.

This is a HRM function that I use only a few times a year; like when I get back to real rides in the spring. It's probably most useful for either someone in training or a person starting out on a cardiovascular fitness program.

There's a chart on the wiki answers link.

http://wiki.answers.com/Q/What_is_a_good_Recovery_heart_rate_level

And another:
http://www.drmirkin.com/heart/8076.html


Is there a hub gear that can be disengaged? When maneuvering a folded bicycle the pedal cranks turn when drive wheel rotates backwards causes difficulty. Do any hub gears have a gear disengage facility to overcome this problem?

Old, plain, one-gear Velosteel-like hubs had this feature thanks to using rollers instead of cogs, but I suppose it does not meet your expectations.

If you REALLY need this feature you can modify Shimano Nexus 3 to obtain what you want by removing four cogs from part no 4 shownhere. You will lose 1st gear, rest will work as before.


SRAM Eagle XX1 Cassette creaking under torque, only after warming up This happens after riding the bike for about an hour. I've replaced free hub, greased/torqued the cassette interface several times, etc. These videos show what I'm up against.
Update: after more googlings on the topic, I found reference to the pins on the largest gear making noise after they loosen a tad, and found recommendation to specifically lube the pins. I tried this with some extra chain lube and it seemed to help, but I haven't ridden the full hour of hard mashing yet to fully prove it out. I suspect these pins are not supposed to be loose enough to allow this, if indeed this is the culprit?
Update 2: oil on pins was not a fix. but I have narrowed it down to the spline finger portion that tightens from the outside- the movement is occurring at this point and making the clicking. It appears there is slop between teh two diameters, and the fingers are pulling from the outside, but allowing it to "shift" and creak under torque.
I read somewhere that gen 1 of eagle had some tolerance issues- is this perhaps what I'm fighting?

The most common cause of this with XD cassettes is simple under-torquing of the "lockring"/locking sleeve/whatever you want to call it. SRAM's number is 40Nm. The sleeve turns with quite a bit of resistance inside the rest of the casssette on XD cassettes, which can lead to not having it actually tightened on right as the friction is eating up torque before correct thread preload is established. You can run a bit of lube down around the sleeve to mitigate that.
If it's not that, and assuming this is some kind of fairly typical cartridge hub, if you're saying there's essentially no change after the steps you've already taken, here's what I would do:

Confirm you can't make the nosie occur when rocking the wheel back and fourth laterally as though to check for bearing play.
Confirm everything is in good condition, clean and properly lubricated with the dropout/hanger. Or just take the wheel out, poke the bare axle into the dropout, reef gently and corrobrate you can't generate any noise.
Corroborate the drive side main hub bearing is in good shape, externally clean and lightly greased, if you didn't already do that when replacing the freehub body.
With those things crossed off, and again presuming you mean to say there was zero change with a new freehub body, it becomes difficult for this to be anything but a movement that's occuring within the construction of the cassette itself. If there's no obvious problem, then what I would do next is take it off and give it a bath with whatever you have handy. If nothing else you can soak in boiling water and a squirt of dish soap, then air dry on a towel. You're not necessarily trying to fix it here, but cleaning it will probably change the noise enough to diagnose. If this route gives you anything, I would suspect a little it's the integral XD "lockring" component of the cassette, and could perhaps be fixed or mitigated by getting some lubrication worked into the interface between it and the rest of the cassette once its clean.


Can the top tube on a mens bike be cut off? I want to cut the crossbar on a mens bike to make it easier to get on and off.  Will it damage the bike?

This is downright dangerous and should never be done on a bicycle someone intends to ride. The top tube is integral to the strength of the bike. The frame can buckle or worse when you try to ride it.

First, make sure you're looking at the right size of frame. If its too big, it's going to be hard to get on and off from. You can buy a stepthrough frame or a mixte frame if you want something easier to get off and on, or a recumbent bike.


What's the verdicts on hub-less circle bicycle wheels? Sturdy and "maintenance-free"? You've probably seen these weird hub-less bicycles, the Reevo and the Cyclotron; while they "look cool" I wonder if anyone has long term maintenance experience on these. Considering that normal hub/dérailleur systems ought to get re-greased and fixed, and any stripped cogs replaced, every 10 years or so, I am not sure I believe the "maintenance-free" claim.
Is this bicycle design too new to be familiar with any bike repair shops... or is the verdict still out on the long term reliability on this design?

Verdict seems to be 'this is a scam'
Cyclotron is a scam https://cyclotronscam.boards.net/board/1/general-discussion
Reevo is suspiciously similar
https://www.reddit.com/r/shittykickstarters/comments/ivk95y/reevo_hubless_ebike_anyone_know_anything_about/
Comments on there about sum it up: looks good to the gullible on Facebook/Kickstarter, in reality is much worse than existing solutions. Hubs & spokes work just great, spokes are fantastic things in that they are each in tension making the wheel strong and repairable.
https://www.cyclist.co.uk/in-depth/85/the-science-behind-spokes
The 'advantage' here seems to be 'not having basic physics on my side, but looks cool'.
One such bike was made an art school product; I suggest that is as far as this will get
https://www.flickr.com/photos/laulaulau3/31994357/sizes/o/
Until these things are actually available and in people's hands, it's best to work on the basis that this is either an outright fraud, or at best will be a terrible piece of junk that works incredibly poorly.
I'm not going to hold my breath to see if my instincts are wrong. But I'm glad you posted this, because I saw these on Facebook and immediately thought 'lol, scam', and now I've done 10 minutes research I'm feeling pretty much confirmed about my theory. But then I am a very cynical person, so.
There is a bit on hubless wheels in general here: https://en.wikipedia.org/wiki/Centreless_wheel  Essentially they are a problem looking for a solution
Edit: I had a look at the technical names given here: https://www.indiegogo.com/projects/reevo-the-hubless-e-bike#/
CEO might have relevant experience https://www.linkedin.com/in/alec-lim-6877821b7/ but it doesn't appear to relate to bicycles or motor vehicles, maybe only robotics
Lead engineer seems to work on microchips in Italy https://www.linkedin.com/in/andrea-stona-87984739/
CTO seems to work for Osram as his day job on lighting, connected lightbulbs, etc. https://www.linkedin.com/in/chewivan/
I get the impression there are a few software people there; how much work they are doing is not clear, but there doesn't seem to be much if anything in the way of 'people who could reinvent the wheel'


Correct position of brake quick release on Ultegra 6800 I'd like to know wether the brake quick release lever on the Ultegra 6800 can be kept in any intermediate position between completely closed and completely opened when riding.

It should be fully closed. The lever is only intended to be opened to allow the tire to pass during a wheel change or if you hit a pothole and knock your wheel badly out of true. If your pads are too close to the rim you make an adjustment with the barrel adjuster. Riding with the quick release open compromises the braking power of the caliper. You may not notice while riding along normally but in an emergency stop at speed it absolutely will result in slower braking.


What is the difference between 1/2'' x 1/8'' and 1/8'' chain size for single speed? I get the difference between 1/8'' and 3/32'', but does this 1/2'' really make a difference, or is it the same thing?

I want to use the chain for track cycling.

That 1/2" is a pitch, ie. distance between 2 pins, which is standard on all bikes, expect, maybe, some super vintage ones. Just forget about it and pay attention to width (1/8 or 3/32").


Chain slipping off from singlespeed rear cog After I have worn out the cogs and chain to the point where my chain tensioner couldn't keep up anymore, I have replaced my drive train pieces, the axle and spacer are still the same.

So I went from:

unidentified front wide/narrow chain ring (42T)
Gusset 1-er converter 15T
SRAM PC-830 (114 Links, 8speed, 3/32")

to:

absoluteBLACK CX Round wide/narrow chain ring (42T)
Shimano CS-MX66 3/32" sprocket 14T
Connex 8SX Chain

I switched from 15T to 14T, there is the usual winter surface grime on it (and cleaned up twice already) and switched the chain/sprocket combination because the Gusset conversion kit seemed a bit too wide for being on spec.

That said, ever since I changed parts my chain keeps slipping off the rear cog and already brought me twice into dangerous situations. I've looked around and tried to eliminate the causes, the chain is straight, the spacers on the conversion kit are just like they always have been, the pieces should individually fit. The new chain is a around half the weight of the SRAM chain.

Pictures:

1st Bolting, 2nd Tensioner, 3rd spacers, dashing is the freehub (approx):

Order of elements:

Closeup:
level clamped to chainring to ensure the chain is straight:
axle picture when I initially bought the bike with the original parts:
picture with chain installed:

Campag toolboxes used to have a tool, looked like a satin chromed steel bar, that was to be placed on the right side of the BB and swung to the left inside of the right frame end. If it didn't just brush nicely, the stays were out of whack. Triple check your BB/cog alignment. All need to be in plane. An aligned chain wheel can't ship the chain off an aligned cog. Determine plane.


How to prevent drafting? I am engaging in a friendly race with a co-worker. He has told me he plans on drafting behind me most of the race to save energy.

I want to make it hard for him(without doing anything mean spirited) to draft off me.  In general, in racing situations, what strategies can you employ to stop competitors from drafting?

In this specific case he is a probably a better more experienced rider and I am the novice.

UPDATE:  Thanks everyone for the advice.  What I decided on doing were some intervals so I was not going at a constant pace.  I wanted to go my own tempo, and if my coworker wanted to draft bad enough(he didn't) he would have to go my tempo.  A side note, I got a better bike which may have more to do with the win then preventing him drafting, but a win is a win.

In road racing there are lots of way to try and gain an advantage (or not to give others an advantage).  Because this is a friendly race, I will break it down into friendly, indifferent and hostile tactics.

  Update 1:
  The OP updated their question to make it clear that they were a beginner and the other rider was a more experienced road rider. So I have added a paragraph at the bottom discussing the importance of how a tactic or strategy is executed.

  Update 2:
  A fun video:  How To Get Rid Of Wheelsuckers

1) Friendly tactics

These tactics are intended to keep the competition friendly by letting your friend draft, but with the intent of making a decisive move at some point to win, which will clearly demonstrate that you were the stronger rider on the day.

First over the line wins -  Simply put, keep the ride relaxed until near the end, then launch and maintain a strong attack that your friend cannot match.  This keeps them in the "competition" until the end, they save face by staying in until the end and you save face with your devastating tactic.  You can even let your friend take pulls to make it look fair.  The down side is that they may come away thinking the competition was closer than it really was.
Sustained Efforts: There are a couple situations where the advantage of drafting is reduced, you can then use these situations to launch a sustain effort in an attempt to ride them off your wheel, thereby gaining the advantage.

Climbs: As many others have pointed out, a significant climb is a good way to put distance on another ride.  Depending on how badly you want to rub it in you can control the distance.
False Flats: False flats are sections that appear to be flat but are actually have a slight incline.  If you do not have a computer that shows this (e.g., Garmin) the slight inclines can make you feel very slow.  Attacking with a sustained effort on a false flat is a great way to put a gap on someone, especially if you know it is a false flat, but they do not.

2) Indifferent tactics

These tactics are a little more aggressive than (1) and may be fair game depending on your friendship and views on competitive behaviour.

Surge Attacks - If someone is drafting a good way to shake them time a short attack where you can put a bit of distance and break their draft, thereby negating their advantage.

Fast/Faster - For example you can ride at a strong tempo, wait to see if they are straining then do a short burst attack to gain a gap.  They will be tired from holding on earlier and now suddenly out in the full wind.  This will demoralize them greatly.
Slow/Fast - Similar to Fast/Faster you will be using changes in speed to break a draft.  In this case start to casually slow down, this will usually leave someone wondering what is going on... then attack to open a gap and break a draft.
Change direction and surge - If you change directions suddenly (e.g., zig or zag across the road, but no zig-zagging) while surging you can instantly remove the drafting advantage which can make it more difficult for the drafter to close the gap. (thank you @altomnr)
Catch them when they are sleeping  - Wait until there is a real lull in the "competition" to suddenly surge and break the draft.
Conversation to attack - At some point get into a friendly conversation, build a story and just as it starts to get really interesting (and your friend lets down their guard)... attack!  Catching someone off guard is a quick way to break a draft.

Using the wind:  If you live in a windy area and you know the route you can

Attacking into a headwind: this can be used in multiple ways.  One of the best ways is if you have an out and back course with a head wind on the way out, attacking a few km before the turn-around can be a decisive way to score a victory.
Guttering: If you get a cross wind (that requires an echelon in order to draft, you can ride next to the edge of the road to "gutter" the drafting rider.  Because draft position is effectively off the road-way and they cannot move off the road way into the draft they lose the ability to draft and have to do the same amount of work.  This is a good time to attack.

Repeat attacks: If you are in a lot better shape you can launch a series of repeat attacks in quick succession.  They may be able to hold on to one or two attacks, but stacking the attacks will eventually wear them out.

3) Hostile Tactics & Cheating

Depending on how much you value your friendship (e.g., frenemies), there are also some hostile techniques that I have come across in races over the years.  I document them for completeness sake to indicate what should generally not consider as a strategy.

  WARNING: In no way should the "forcing an error" tactics be used against your friend as these tactics can potentially send someone to the hospital.

Forcing an error:

Attacking on technical descents:  If you are a more skilled descender you can use this to your advantage by encouraging someone to try and keep pace, thereby taking them out of their skill level. People will often over shoot corners and otherwise get shaken forming a gap.  At worse you may cause someone to crash and have an injury.
Overcooking corners:  Another horrible way is to deliberately overcook a fast corners so that you can just hang on, but with the intent of forcing them to go off the road or crash.
Riding into hazards: Another way to shake a drafter is take them into hazards such as pot holes, or riding within less of an inch of the side of the road.  The idea is to fake them into letting off.
Brake checking:  There is a special place in hell for those that brake check, but it is effective way to shake someone.

Using a vehicles wake.  If you are a stronger sprinter jumping into a vehicles draft for a period of time allowing you to surge ahead
Lie: While your friend is drafting casually say: "You know I am just not feeling it today... do you want to call it quits?"  Then while they are thinking follow this with a decisive strike.
Change the goal posts:  Near the end if your friend is still drafting suddenly sprint for a arbitrary close finish line.  Claim victory!  As an extension, in the post finish confusion, attack again to actually win.

The Importance of Execution

The tactics and strategy outlined above will rely heavily on execution, which can be difficult for beginners.  Many new riders will only partially commit to a tactic, holding back for fear that it might not work out. The "secret" is that once you decide on a tactic you really have to commit everything to it (i.e., willingness lose and look like a fool). Otherwise it is only a half strength attack which is easier for the other rider to survive. The more experienced rider will be practiced in the determination needed to knuckle down and survive an attack (even though they may be less fit overall).  This mental strength and experience can make them a formidable opponent if you do not fully commit to a strategy or tactic.

It can take time and practice for beginners to develop the "killer" instinct needed for success, so don't get discouraged if a chosen strategy doesn't work first time out. Sometimes you just have to keep throwing mud at the wall to get some to stick.


Why can't Yellow Jersey change hands on last day of Tour De France? I've often read / seen on TV that the race is won by the end of the penultimate day. For example, this article in the Guardian describes this year's (2011) eventual winner as the champion elect in an article on the close of the penultimate day. The final day seems to be left to the sprinters.

Why is this? Surely if the top two riders are very close the guy in second place can go for it.

Tradition, and the layout of the final stage.

Tradition holds that the last stage is a victory parade for the GC contender, and the yellow jersey. Cadel Evans rode a good part of the 2011 final stage, once in Paris, with champagne in hand.

In addition, the layout of the stage, a 95 km flat ride finishing with multiple laps around the Champs Elysees, and culminating in a bunch sprint, rarely allows the opportunity for any major time to be gained. So unless they are within seconds, as in the 1989 Greg Lemond win by 8 seconds over Laurent Fignon, the last stage will rarely play a part in the GC standings.

As is stated in the description of the stage on the letour.fr page today:

  Every other time, it has been a road stage that has been decided in a bunch sprint, except on four occasions. Those exceptions were the victories taken by Alain Meslet in 1977, Bernard Hinault in 1979, Eddy Seigneur in 1994 and Alexandre Vinokourov in 2005. It is incredibly hard to get a telling gap on this stage when breakaway riders are always within sight of the peloton.”

If you know that a breakaway will not gain you minutes, why risk the ire of the other riders, and your public by messing with the traditions of the race?

One of the things that has always brought an audience back to this race above all others are the traditions of fair play and honorable conduct that are embodied by traditions like the one that allows a crashed race leader to regain his time by the other riders, before the race continues. These unwritten traditions are not rules, but they make this race special.

Combine the two, and you will rarely see a major change on the last day. It can, and does happen. Just not often.


How long is the life cycle of a bicycle? This may not be a particularly practical question, but I wonder how often do you find yourself looking for a new (or another) bike? There are, of course, two main aspects of it:

Mechanical decay. If you drive a car, you know to lube it every 3000 miles, rotate tires every 7500 miles, flush the fluids every 30000 miles. If you are reasonably serious about riding a bike, you'd place yourself at wherever you are comfortable in terms of maintenance from being unable to adjust your saddle height to re-assembling your own spokes and hubs, but you'd do some maintenance, anyway. Most components would have reasonably well-defined span they will serve, and would probably start falling apart after this many miles, even with reasonable maintenance and repair. What would the range in time and/or miles be for commuter bikes? road bikes? mountain bikes? Or are the modern bikes of say $1000 and upwards basically perpetual, unless you ride one heads-on into a concrete wall?
Needs change: you outgrow your bike, your riding pattern changes, you switch from group rides to triathlon, you move to a new area, you hand down your bike to your younger sibling, etc.

I have a gut feeling that the latter is far more likely to happen than having the bike used up to its full mechanical resource. Any opinions?

Let's try to steer this into some kind of sensible question with the perspective as seen from a typical bicycle shop workshop and what is on the road.

In a bike workshop you can find yourself working on bikes that can be up to fifty years old with a large quantity of them being more than ten years old. Some of these bikes have not been out of the garden shed for the last five years and have suddenly came into use because the owner's son or daughter has started riding.  Therefore this question very much depends on how often the bike gets an airing, how it is stored and how much it gets maintained.

For the person using their bike every day for commuting, the lifetime of the bike is an economic question. After five years or so, even with brake block changes, new cables, maybe the odd new set of sprockets, new tyres, replacement chains and plenty of t-l-c, the bike will suffer all-over wear that costs almost as much as a new bike to put right. Wheel rims will wear through, saddles will get torn,  bits of 'Shimano plastic' will go missing and the whole drive-train will get worn.

Fixing these problems will typically necessitate another round of consumables, e.g. chain, cables, brake blocks and tyres. All of these are more expensive as spares that you have to put time into fixing or pay a shop to fix. Meanwhile, at OEM prices, pre-fitted to a new bike, a better deal can be found. The existing bike has 'depreciated' to become a liability much like how an old car does.

If you look at the cars people drive you will notice that there are not too many 'Ford Cortina' models on the road. (UK) There are not too many 'Ford Sierra' models on the road either. Yet, there was a time when every other car was one of these models. There are one or two of these left and you do see them once in a blue moon, so clearly it was possible to service them and keep them on the roads forever. However, that did not happen for 99.9% of these once popular Ford cars.

Now have a look for what people actually ride. There is a reasonable selection of twenty year old models on the roads used by people on the commute or taking the dog for a walk. However, depending on where you live, the majority of bikes are recent, i.e. less than ten years old. Half of those are very new, less than three years old. Most of these 'daily riders' are well on their way to being used up as a 'mechanical resource'.

As for your point 2), in the UK many bikes get abandoned by their riders when they take up driving. Before people get to that age they do go through a series of bikes that they grow out of. Competitive riders are different again, typically they have a fleet of bicycles and a ludicrous amount of spare parts left over from upgrades.

To summarise, a bike will have a lifetime of approximately five everyday-riding years before it gets shot to pieces. This lifetime can be extended indefinitely through new components and diligent maintenance (or instantly shortened in the case of a crash). In reality people can ride bikes long after the bike is past its best, they can also put the bike into storage for long periods of time and they can also get into the sport (to purchase many bikes that don't necessarily get worn out).


How easy is it to remove a seat with a dropper post? I recently got a shop to install a dropper post on my mountain bike and just now realized that I have to take the seat off in order to fit it on a car boot rack. Is it straight forward to take it off the bike? Does the control cable disconnect from the post?

I don't want to pull it out and then fish for the cable inside the frame.

The post is an internally routed Giant Contact Switch.

I just installed my own 2016 Giant Contact SL Switch dropper post in the internal cable routing mode this week.

The simple answer is you would be best advised to just remove the seat itself by undoing the clamp bolts with the appropriate hex wrench, leaving the post itself installed in the frame. If that solution does not sufice, then opt for external cable routing, or give the folowing a try...

Long answer (Not recommended):

To remove the post you would have to loosen the set screw on the handlebar switch that fixes the inner cable. Since the set screw tends to crush the cable, it may not thread out of the housing well or thread back in easily (requiring replacement of the cable...).

If the cable end isn't totally crushed/unusable, then pull the section of housing away from the switch and put the short section of adjustable length housing in your pocket. Now you have to simultaneously lift the seat post out while pushing the housing through the frame from the handle bar side, ensuring the housing does not get pushed through the internal routing port into the frame downtube. If you don't have sufficient housing length between the handle bar and the port, then try pushing the cable through as much as you can for a little extra wiggle room. If the post is now completely outside of the seat tube, then you can just disengae the cable from the bracket on the post (no tools required).

The problem then is reinstallation of the post. You would have to re-engage the inner cable to the post (possibly having to invert the bike to get the bobbin to slid to the end of the cable), and then reinsert the post and reverse the earlier process - this time pulling housing/cable back through while lowering the post in. Then you have to put the length of adjustable housing back on and clamp the cable at the switch. Of course, as stated earlier the cable may need to be replaced it the end is too crushed.

All in all, much too much work to repeat. Hopefulyl just removing the seat from the post is sufficient, and you don't have to remove the post entirely. Because with the internal cable routing removing the post is cumbersome/likely something you only do once. External routing of the housing/cable would make the job easier.

In that situation you could get away with leaving the cable a bit long, taking up tension with the adjustable housing section, and then just loosening the adjustable housing and un-clipping the cable from the post to remove the post. Probably. You'd have to try it and see!


brakes for carbon rims I'm considering switching from alloy to carbon wheels - just a question regarding that & brakes. Would I need different pad materials from the standard sort of pad material (or even a whole different type of brake mechanisms)?

Most carbon rim manufacturers like zipp and enve recommend a brake pad of their own.  However, there are typically several pads that will work.  Most of these pads are designed specifically to work well on carbon rims. Regular brake pads from alloy rims should not be used on carbon.

Zipp recommends the following pads for their rims:
Zipp Tangente Platinum Pro
Zipp Tangente cork pads
Bontrager cork pads
Zipp carbon/carbon pads
SwissStop yellow pads

So, I would check with the manufacturer of your rims to see what pads they recommend and stick with those, otherwise you could be voiding your warranty on an expensive set of rims.

Leonard Zinn (author of Zinn and the Art of Road Bike Maintinance and owner of Zinn Cycles) recommends against using regular pads on carbon rims.  See the following from the article in velonews:

  I can say from personal experience that standard brake pads on
  carbon rims are grabbier, giving louder, less predictable, potentially
  dangerous braking, and they wear faster, even melting down rapidly at a
  critical moment on a long, fast, tortuous descent, leaving you with no
  brakes at all. Furthermore, conventional pads on carbon rims are
  down right scary in the rain, making for unpredictable braking until the
  rim is wiped clear of water enough for them to grab.


Turning MTB to hybrid I have one mountain bike with its own tyre. I would like to turn that to a hybrid. My MTB tyre size is 26×2.125 57-557 what size should I purchase if I am going with hybrid tyres?

You obviously need a tire of the correct diameter for a "26 inch" wheel - These may be marked 26" or ISO / ETRTO 559.
Generally you'll want a tire narrower than a MTB tire for on-road use. Narrower tires running a higher pressure have less rolling resistance.
How much narrower is up to you depending on the roads or trails you want to ride on, but you are limited by the width of the rim. See What is the maximum or minimum tire width I can fit on my bicycle.


Movement in head tube/fork? I have a BH road bike and it has some movement with the tube that connects to the fork.
I took it to a bike shop for a tuneup. When I picked it up the guy mentioned the issue. He said he tightened something (I forgot what it was) but it didn't fix it. He then suggested that I needed to change a bearing (or something) inside the frame (where it's circled). The guy said that it may crack the frame since I'm riding and the tube is moving around.
It moves very little from side-to-side, and I don't actually feel it. But it got me a little worried after he said that it could crack.
Here's a picture of the small gap: in the left I'm pushing the handlebar towards the front:

Is this something that can be fixed?

The tube you’ve circled is the head tube. Inside the tube, on the top and bottom are the headset bearings which allow your fork to turn smoothly.
The bearing play or preload has to be set correctly with the vertical screw on top of the stem cap.
If there is play in the bearings allowing the fork to rock back and forth you’ll have to adjust the preload. To do that you have to loosen the two screws on the left and right side of the stem which clamp the stem to the steerer tube. Then slightly tighten the vertical screw until the play is gone. You shouldn’t need force, we are talking <2Nm torque here. The fork should still turn freely, if it doesn’t you’ve tightened too much. Afterwards, make sure the stem and handlebar are aligned correctly to the wheel and tighten the two screws to the left and right.
See this tutorial: https://www.pinkbike.com/news/tech-tuesday-headset-adjusting-2010.html
Since you have carbon components you should use a torque wrench to tighten to the specified torque.
If the steering feels rough the bearings are worn and have to be replaced. If you suspect bearing damage it could also be a good idea to completely remove the fork and take a look at the bearings directly and how smoothly they run.


What does EN 14781 certificate mean? This is a old (replaced by another certificate around 2014; ISO something) certificate for racing bikes given by European Committee of Standardization. (EN 1xxxx for another types). But what does this cert mean? If my bike has this cert, does this mean -my bike is a racing bike- or -my bike has a safety level of racing bikes standards-.

The British Standards Institute provides the following summary:

BS EN 14781:2005 covers the test methods applicable in the design and manufacture of racing bikes.  It was developed to ensure the strength and durability of individual parts as well as of the bicycle as a whole, demanding high quality throughout and consideration of safety aspects from the design stage onwards.
This European Standard specifies safety and performance requirements for the design, assembly and testing of racing bicycles and sub-assemblies, and lays down guidelines for manufactures instructions on the use and care of such bicycles.
BS EN 14781:2005 applies to racing bicycles intended for high-speed amateur use on public roads, and on which the saddle can be adjusted to provide a maximum saddle height of 635 mm or more.
This European Standard does not apply to mountain bicycles and to specialised types of racing bicycle such as tandems or bicycles designed and equipped for use in sanctioned competitive events.
For bicycles with a saddle height of ≤ 435 mm see EN 71 and with a maximum saddle height of more than 435 mm and less than 635 mm see EN 14765.

Standards documents themselves are usually rather expensive (£254 for this one, even though it's obsolete) so I doubt many here have access to the full text.


How to repaint a Carbon bike frame? I have recently purchased a Specialized Roubaix SL4 Elite Disc carbon frame bicycle - But I am not particularly happy with the colour. It is charcoal and white. I like to have a brighter colour.
Is there a way to repaint a carbon frame or at least change the white pin stripe to a bright green.
Thank you for your kind contribution.

I'd avoid doing this.

Basically, you do a light (typically wet) sanding by hand (very carefully), prime it with an appropriate primer (maybe a few times) and then paint over it with an appropriate color. However, since the sanding has to be done carefully (since its easy to destroy carbon fiber by sanding), you're going to end up paying someone a lot of money to do this (since it takes a lot of time to prep the frame).

You can't really use chemical strippers or other techniques that you'd apply for aluminum and steel frames can destroy the carbon fiber. You also can't do things like powder coating for the paint step, since you have to heat the frame to the point where the carbon fiber can be destroyed.

If you're really insistent on doing this, there are shops which specialize in repainting carbon fiber. But, they'll charge you an arm and a leg due to the amount of labor they'll have to put in to prep the frame for repainting.


Hydraulic to mechanical conversion - cable routing A family member has asked me to convert their hydraulic disk brake system (an old Hayes So1e) to cable disk brake. I believe the bike is only going to be used casually, so performance isn't paramount, it just needs to work.

The image shows the hydraulic hose for the rear brake running along the middle of the top tube. What would be the best way to implement a cable? The tube is slightly square shaped, so I think it would be difficult to fit a clamp-on cable stop (and would also interfere with the gear cables). If I omit cable stops, use uninterrupted housing for the whole length and use zip ties to secure it to the frame, I'm thinking there might be issues using barrel adjusters.

You can run the cable outer housing exactly the same as the hydarulic hose.

The main reason for using frame stops is to provide sections that don't suffer from compression of the outer housing under load.  A full run of brake housing could compress and use some of the braking power.

You could solve this by using compressionless brake housing, which has multiple metal bracers instead of a continuous coil.

NOTE I am NOT suggesting to use gear housing as brake housing.  They're different thicknesses.


Have there been designs of bikes with stepless transmission? Today we studied about mechanical stepless drives, which appear to be used quite widely in industry machines, such as CNC lathes.

The concept of varying the transmission ratio arbitrary, without fixed steps, seems tempting for a bike. Has it ever been tried commercially?

There have been designs, but cyclists tend to be picky about increases in weight or losses in efficiency.

Bicycles do not have the problems of large spinning masses or rough clutching at low speed, and we seem to do OK with discrete steps in the gear ratio.


Stripped thread on steerer. Who is at fault - me or LBS? Background
I ride a Peugeot PKN10 (1980 or 1979 I'm unsure of the exact date).  Three months ago I had a cracked chainstay replaced at my LBS.  This required removal of the original fork and headset so the frame could be clamped and welded.
When rebuilding the bike the LBS recommended that I replace the original headset (a vintage Lightrace model I believe to be this one) with a modern headset, advice which I took on the basis of their expertise.  The listing for the linked item notes that the Lightrace headset is French threaded.
The Issue
The new headset the LBS fitted was (what I know know to be a British threaded) Tange Passage.  I was told this might loosen after a bit of riding and if so to return to the shop for an adjustment.  When I got the bike home I noticed the top adjustable race was so loose it could be turned with my fingers.  I returned to the bike shop for an adjustment, which tightened everything up.
I then rode the bike for 2 months. After around a month the top race of the headset was noticeably loose again, and I made the adjustments myself (as it was not convenient to return to the LBS).  My daily ride is approximately 5 miles, in heavy traffic in a busy city - as such I couldn't hear or particularly feel grinding in the headset.
On a longer ride in the countryside (approx 25 miles on country lanes) this became very clear though - after 5/6 miles the headset became so loose I could turn it with my fingers again and I rode very cautiously to my destination and back again (there was no opportunity to 'turn back' and resolve the issue when I noticed it).
It was clear at this point that the issue lay with the headset slipping on the thread of the steerer. Immediately after the countryside ride I removed the headset and fork off the bike completely.  The thread of the steerer is clearly stripped, as well as the inner thread of the locknut.  The LBS has advised that both now need to be replaced.
The Question
After seeing the steerer and doing my own research online I believe the LBS fitted the incorrect thread of headset (they are currently checking to see whethet this is the case - I will update when I have a definitive answer). My conclusion is that an incorrect headset was the root cause of the damage.  The LBS has said that I should have come in sooner if I noticed the headset was loose and not ridden the bike for 2 months - they believe I have caused the damage by not acting on the signals earlier.  The LBS has not brought it up, but there is of course the matter of the adjustments I made myself - possibly these caused irreversible damage to the steerer.
My assumption was that the bike shop would diagnose the correct thread type of the steerer and fit the correct part, and as such I when adjusted the headset I was doing so on the basis that it had been correctly installed and therefore could be easily adjusted without damaging the steerer.  Equally, doubt I had as a result of noticing the headset loosening on a number of occasions was counteracted by trust in the LBS - my assumption was the bike was fine to ride as the initial work had been completed by professionals.
Between a new fork, a new headset and labour (£80 + £20 + £15 = £115) this has become costly to resolve.  It's also notable that I have already payed £35 for the (arguably unnecessary) Tange headset and the labour to install it.
My questions here are threefold:

Can installing an English threaded headset on a French threaded steerer cause this type of damage?
Who does the fault lie with here - me or the LBS? Who should bear the cost of the resolution?
If the resolution is to meet in the middle (registering responsibility to both parties), what is a fair way to split the financial cost between myself and the LBS.

Absolutely.
If they actually put anything but a French headset on a French fork, it should be 100% on them.
Hopefully they will fess up and cover the whole thing.

Just to be clear, measuring the difference between a French fork and the more common ISO/British is super easy. The OD of a French steerer is 25mm, and common 1" is 25.4. The thread pitch is also different. The parts just don't fit right together. Making this mistake and sending it out the door without noticing anything amiss is implausible.

Also, if you did have a French fork and it's being replaced with ISO, they owe you a new stem too because the quill OD/steerer ID is .2mm less on French than ISO.


How bad is handling with only front aero wheel? I think it's obvious that the only reason to have aero wheel at front and regular wheel at rear is budget. I did some research on this and what I found was aero front wheel is more important and rear aero wheel is only to help bike handling despite the fact that most people use deeper rear wheels. Most stuff I read were from > years ago, wonder if anything changed (newer wheels handle better in crosswind maybe, etc.)

Edit
To clarify, some information that I found claim that using front only aero wheel results in worse handling than having front and rear aero.

So, can anyone confirm this and maybe someone with experience in using such setup. I want to know how bad handling can be with 50 mm front wheel and regular wheel at the back.

First, running an aero wheel in the back does help with drag, just not as much as the front. A 50mm section aero wheel in the front with a standard wheel in the back will be fine. It may look a little funny, but it won't make the bike unridable. That said, a deep section rim is a deep section rim, and it will cause some deflection from your course in crosswinds.

EDIT: in the case of a windy day and front only aero wheel, your front end is going to get pushed around more than your back. If you're running both front and rear aero wheels, you're going to get pushed around more evenly, but you're going to get pushed further. Neither situation is pleasant, especially if you're using clip-ons, but I don't think that going with only a front aero wheel is necessarily worse. It is a setup I've used in the past, and a setup that I think isn't altogether uncommon in lower categories as racers are more likely to borrow just a front from a fellow racer for a cat 5 time trial. If you're dead set on getting an aero wheel I wouldn't let potential handling differences vs a full set stop you.


Why is cross chaining 'bad', but 1x is OK? When you run 1x, aren't you basically force to cross chain?

One key difference is the design of the chainring. A traditional ring is made to allow shifting, which means there’s specially shaped teeth and protrusions that will pick up the chain and help lift it in to the next gear.

Cross chaining with traditional rings will put the chain in the angular region where it ‘thinks’ you want to shift (ie. these mechanisms will start hitting the chain plates).

On a 1x system a narrow wide ring is typically used, or a similar device, that meshes more completely with the whole chain link. Since it doesn’t have to worry about shifting, it’s only worried about retention, so it can ease the chain into a consistent position from a wide variety of angles.

As for the rear derailleur, they’re designed to rectify the angle as well, with SRAM opting for a more eccentric pulley position relative to the pivot, and Shimano using differently shaped parallelograms. Both these systems keep the pulley a consistent distance away from the sprockets, so the whole system can accommodate wider chain angles.


can bottom bracket type be determined without disassembly? Is it possible to determine wether my BB is press fit or threaded w/out disassembly?  It's XT 8000 if that helps.

If your BB uses a threaded interface, there will be a tool interface.

For Shimano Hollowtech II style cranksets, threaded BBs sit outboard of the frame with notches needed by the tool clearly visible.

Frames which use Shimano BB86/BB92 pressfit BBs use a wider BB shell. The pressfit cups will have a thick lip that prevents them pushing deeper into the shell. The shell inner diameter is 41mm, so the diameter of lip should be about 43mm.

Cranksets with 24mm axles can be used in frames originally designed for 30mm axles, either by fitting a special BB whose bearings have a 24mm inner diameter or are sleeved to 24mm, or by fitting an adapter which reduces the shell diameter to allow a normal BB92 or external threaded BB to be used. BB30 shells have 42mm ID; PF30 shells have 46mm ID.

If you have a Trek, you might have a BB95 pressfit BB with shell ID 37mm.


Why did Shimano name them V Brakes? Why did Shimano name and trademark their variety of direct pull brakes: V-Brakes®?

Is it because of shape? The two arms look kind of like a V? That seems a fail as they are more parallel than most cantilever brakes, which are much more V-ish.

Is it because there were earlier series: I, II, III, IV, and finally V brakes?

Historical references please.

Apparently they were invented by a guy called Florian Wiesmann who called his brakes "Wies-brakes", which sounds a lot like "V brakes" to an English speaker.

In 1991 he made this brake:

Apart from the centred brake cable attachment, that's very much like a modern V brake. By 1996 he had something you'd look at and swear it was a slightly fancy-looking V brake clone, and that seems to be the year Shimano introduced the V brake.

In 1991 Ben Capron was also selling his Marinovative V brake that also looks just like a modern V brake. IRD also began selling their Widget brake. So "who invented the V brake" is a complex question and it may well have been a parallel discovery.

Mombat say on a link I got from Google cache because the page doesn't appear to exist now:

  [IRD] Developed the Widget brake, because they needed a brake that could mount to the rear swing arm. This and the Marinovative Brake are the progenitor to today's V-brakes.


How do I make the platform side of a Shimano PD-A530 multi-purpose SPD pedal less "slippery"? The lock side is great, however, shoes does not stay on the platform side. Your leg always slip out from the pedals during pedaling. Any solution to improve it?

Some people have modded the pedals to add set-screws which provide better grip.  Typically this involves drilling a hole, tapping it for threads, and adding a set screw of the desired length.

For example, here's an a530 with 2x set screws added:


Describe main criteria of choosing energy-conserving bicycle that allows getting easily up-hill It's summer now and it's hot. The way to my office is up-hill (half of the way is off-road). With my health it's not a good idea to work hard physically in such whether. And there is no shower in office. So could you please describe main criteria of choosing a bicycle that allows getting up-hill with less effort? I mean the tradeoff between speed and force - I want to reduce force. I would appreciate two options (without engine): less and more expensive.

Uphill - gears and weight. Extending the lowest gear range till its faster and easier to walk and push the bike is cheap and easy and would be the first thing on my list to do.

Cutting down weight (of the bike) is an has an exponential cost/gram relationship - you quickly get from $1/gram to $100/gram. Cutting your weight does not require the cash, and in most people cases a very effective way to gain speed uphill. (Shaving 5kg off a bike will cost $1000's, even if possible, many people can afford to loose twice that).

Although you said no engine, in your situation (hot, uphill, no shower at end, health concerns) a pedal assist electric bike would be a very effective way to achieve your apparent aim. Would you be prepared to rethink that position and consider an eBike?


What could have caused this flat? Today I encountered a puncture. I pulled the tube, ran my fingers around the inside and outside of the tire carefully looking for the offending object, found nothing, so concluded it was probably a pinch flat (I had just hit a pothole).  I installed a new tube, being careful to seat it properly to avoid pinches, and re-inflated.  Within seconds the second tube was flat.  That being my only spare tube and my only CO2 cartridge and it being dark and a very long walk home, I called the sag wagon (aka my wife).

Back home, I removed the tire from the rim, turned it inside out, inspected carefully, and found nothing.  Ditto with the rim and rim tape.  And, I should add, these are virtually new tires and rims with barely a hundred kilometers on them.

When I looked at the second tube that failed, I found this:

Those slices are directly opposite the valve stem, and a careful re-inspection of the tire and wheel at that location revealed nothing.  But as you can see, they're quite large slices.  I might suspect a faulty tube if it were just one slice, but two?  That seems extremely unlikely to be a faulty tube.

I know no one can tell me exactly what happened, so my question is what are the possibilities?  What the heck could have made cuts that large that occurred without even riding on the wheel and which couldn't be felt with my fingers on inspection?

I patched both tubes yesterday, partially inflated them, and let them sit overnight (without being in a tire).  One of them was flat today, so I tossed it as probably having an unseen slow leak not worth finding.  The other one I remounted and rode 40 miles today without problem.  So apparently either: 1) I somehow damaged the second tube mounting it, or 2) there was something in the tire I never saw or felt on inspection and it fell out without me noticing.


Should I put grease on the surfaces of a back pedal internal brake? When servicing a back pedal brake hub, should I put some grease on the internal brake surfaces or not?

Is grease good because it makes the brake run smooth, or bad because it makes it slip and not work so good?

There is no part inside a coaster brake that can be harmed by grease.  You do need to use a high-temperature grease though, friction makes them get quite hot.


Why can compact frame in road bikes be made in less sizes than the traditional frame? When I read about Giant, they talked about how in the past road bikes have to be in like 10 incremental sizes, but Giant had an idea from a mountain bike (which usually only have S M L sizes) to make road bikes with compact geometry so that it can be made with bigger jump in sizes.

How does this work? why a traditional frame can not be made in the same jump in sizes?

No matter how I compare the frames, I can't wrap my head around how a compact geometry can cover wider possibility of sizes that the traditional frame does not. The head tube angle is the same, the seat tube angle is the same, so raising or lowering stem and or seat post will be no different regardless if it is a traditional or compact. It is not like compact geometry can have adjustable stack and reach.

The claim is pure marketing and does not make any sense at all, unless you only care about standover height. It is true that Giant has smaller selection of sizes than competing manufacturers, and Giant might use the claim to explain why, but even their own models are not consistent with the explanation:

High end Giant models have 6, not 3 frame sizes. This is not that many less than competitors who have 9 or 10.
Giant has a series of non-compact "aero" road frames. These also come in 6, not 9 or 10 sizes.

On the other hand, smaller selection of sizes reduces tooling and inventory costs. If a sponsored athlete requires a bike outside standard selection, it is easier to provide them with custom frame than mass produce the wider selection of sizes.


What is the plastic inside this barrel adjuster, and is it okay to be worn? I'm replacing the brake cables (inner / outer) on my ~2 year old bike, and noticed that there is a piece of hard plastic tubing (2–3mm diameter) inside the metal part of the barrel adjuster that feeds it between the handle and the outer tube.

Does this part have a specific name? I've tried searching for barrel adjuster "inner plastic" and haven't found much online.
How necessary is it for functioning brakes / avoiding cable wear?
I can't find any similar plastic tubing locally, nor spare parts online.
Would it be alright to just keep it in the barrel adjuster, even though it is quite worn and split at one end?
...Or could you even just do without it completely?
Thanks!
Edit: As per comments and solution — it appears to be the same teflon sleeve that can be found inside the brake cable housing.

I do not have the name of the part, but it's likely that it is a Teflon sleeve. A similar piece is found inside linear pull brake noodles. In cheap ones it is just plastic. In good quality ones it is a somewhat resistant plastic with very low friction (I'm not really sure if it's actually made of the material commercially known as Teflon)

In the case or a brake noodle, as you see, it is a curved part so the cable makes full contact with the inner part or that curve and it is subjected to very high force. (I don't know how to calculate, bu I guess its almost all the force your hand can apply, multiplied by the brake lever's advantage).
This sleeve is part of the noodle and I've never found it sold separately, but a noodle is an inexpensive replacement part.
If you needed to replace the sleeve on your adjuster, you could get a sleeve from a noodle, just cut it to size. But also a barrel adjuster should be inexpensive to replace, you may be able to find ones that include that sleeve; although I've never seen a barrel adjuster with a sleeve before.
For MTB brake levers, most designs I've used have a mostly direct cable route from the cable stop through the adjuster and into the cable outer jacket (housing) and there is very little fiction between the cable and the adjuster. So, my guess is that in any of my bikes, if such sleeve where used, It would have got almost no perceivable benefit, and also, very little wear. None of my brake levers has a protective sleeve inside their barrel adjuster.
In your case, it seems like the cable exits the adjuster at an angle and that caused wear as the cable slides back and forth. Most likely you can make your brakes work without it, but the cable will eventually carve a channel into the adjuster, causing more friction and a rough feel when operating the brakes, at which point you'd need to replace the adjuster (They should be cheap, so once with every cable change shouldn't add much to the cost)
In good quality brake noodles that sleeve lasts somewhere between one to two years (In my case usage is once a week MTB use on wet, muddy environment).
All this time Im thinking of the adjuster in the lever assembly (I'm guessig that's what you call the handle) But similar adjusters may be found in cable stops in the frame, in the other end of the cable where it attaches to the calipers or in rear derailleurs.
Some cable housings have an inner protection layer made of similar material. If your replacement housings have it, and you have cut a short surplus, you may be able to extract a piece and use that to replace the sleeve in your adjusters.


Why do bike tires suffer from frequent punctures whereas car tires don't? I have driven in my life 200 000 km by car and 20 000 km by bike. In my car, I have never had a single puncture. In my bike, my puncture count probably exceeds 5.
Why do bicycle tires suffer from frequent punctures whereas car tires do not?

The main reason is that bicycle tyres are much, much thinner than car tyres. A little tetrahedron of broken glass or a drawing pin that would puncture both tyre and tube on a bicycle won't trouble a car's tyre in the slightest.
A secondary reason is that bicycle tyres with tubes have additional ways to suffer punctures: an under-inflated tyre is susceptible to pinch flats.
It's pretty much as simple as that.


Preparing for Alpine riding The general question: What should a reasonably fit cyclist do to prepare for alpine riding, and what adjustments should be made in route planning?

In my case I can do rides of 250 km+ with 3000 m of climbing, but I'll be staying within about 40 km (riding) of Col d'Izoard (~2300 m altitude) in a couple of months and hope to be able to take a bike with me. The major differences I see compared to UK riding are:

Incessant climbs (but I won't be in a hurry and will want to look at the views so can stop).
Altitude: At a similar altitude to the highest points I'm likely to ride, I recall that hiking was harder than expected for a few days. I'll have a week in the area, staying at ~1000 m so will aclimatise a little, but perhaps this isn't quite high enough to worry about anyway even though I live near sea level.
Warmer, drier air.

Compared to sea level and short sharp hills, I don't know if I should be planning shorter rides to take into account the conditions, or whether I should go for something like The 2017 Col d'Izoard Etape du Tour, and if so how I'd train for the latter on local roads near sea level.

I don't have experience riding at moderate altitude (1000-2500m), but do have experience mountaineering in the French Alps (>3000m) and Himalaya (up to about 5000m).

Going to over 2000m altitude is not trivial, even for people in good shape, and can have some adverse effects. It's not something you can totally ignore. Although if you are fit and have experience hiking at similar altitude you will definitely notice the relative lack of oxygen but avoid any serious issues.

The most important thing is to drink tons of water, which helps with some of the immediate physiological effects of working at altitude.

As your accommodation is relatively low you will have a chance to recover each night. The mountaineering mantra for acclimatizing is 'climb high, sleep low'.