What are the downsides of a twisted wheel? After a collision where somebody fell on me, my front wheel is twisted to the point that it slightly touches the brake once per revolution causing a soft screech. Logistically, I can't get to the shop to repair it right away.

First, is this condition dangerous? Should I stop riding the bike until it is repaired?

Second, if there is no danger, what are the pros and cons of repairing it at all as opposed to leaving it that way? This is a cheap bike I bought used, and if they need to exchange the whole wheel, it might cost more than I want to pay. I find the sound slightly annoying, but not terribly intrusive, and if there are other influences on the riding experience (slower speed?) I haven't noticed them. The light dynamo still works.

If it's relevant, I'm talking about a simple Dutch style bike without any fancy parts. I only ride it on paved flat streets.

You are lucky to have V-brakes, because they make repairing the wheel yourself an easy half an hour task. Plus the tool is $2 usually.

Spokes pull the rim one way or the other (look at the spokes and their angle from the hub flange to the rim). If you tighten a spoke, it pulls the rim away. So, you 1) tighten your brakes barrel adjuster until they rub heavily 2) tighten the 2-3 spokes around the dent to pull the rim away 1/2 or 1/4 turn and loosen the the same amount the spokes, pulling the rim the other way 3) repeat many times, until there is nearly no rub 4) loosen the brake's barrel adjuster to the normal riding setting.

If you don't fix the wheel, it will be easier to get damaged the next time. That's it.


Life expectancy of a rim? I've erroneously bought a rim (hoping my technical English is right: the part of the wheel between the spokes and the tire). While I have no immediate use for it, shipping it back to the seller for refund would be a waste of shipping costs if I would need a new rim in the foreseeable future. I have been riding a Gazelle street bike for ~10 years now, and it is showing signs of wear along the periphery. In particular, I've recently discovered I've been negligient with checking the spokes of my rear wheel, which has been running some time with broken spokes. For the second time now in these 10 years.

How long can I reasonably expect rims to last on a street bike? Will I be facing replacements sometime soon?

Rims can last a very very long time.

The failure mode (other than from accidents) is simply the wearing-down of the brake surfaces over time (see this question). You can literally wear-away the rim surface with your brakes until the rim is too weak.

Some rims designed for commuters have a groove in them that is designed to indicate wear. When you can no longer see the groove, you know its time to replace the rim (might as well replace the wheel).

Here's an excellent description of rim wear.


practical pro and contra for Nuvinci CVT especially for hilly terrain I'm thinking of buying new bike next year, most probably combo for exercise & commuting in summer. Since terrain is relatively hilly here and both fixed city-bike and casual combo with 3x7 gears making me too much tired, I thought of buying as additional item NuVinci Mondo hub. Reviews are mostly positive but I'd like to read real pro and contra, not paid-by-manufacturer-or-reseller review. Do I win anything real for that price? Or is this just money waste? What are maintenance costs and issues?

The NuVinci system is fantastic in principle and one day all bikes might come with it, but we aren't there yet. As the system stands there are a few matters that might not make it the answer to your prayers of an easier time going up hills:

For hilly terrain you need gears - it goes without saying. The steeper the hills the bigger range of gears - going up you may need a 'granny gear' and going down the hill you need a big gear (unless you don't like speed and coast).
This is the potential problem area with your intended application. The NuVinci hub has a range of 350% - exactly what that relates to depends on your spocket/chainring choice. Meanwhile, with a Rohlhoff or basic derailleur setup you are going to get a range of around 530%. Touring bikes and XC-MTB's usually come with an even greater range, however, do you use the 'granny ring'?
Note that early adopters of the NuVinci hub seem to be primarily in Denmark and the Netherlands, where the terrain is flatter than the North Sea.
There is also the small matter of efficiency. With a derailleur gear setup you can get an amazing 98% efficiency when on the middle ring and middle sprocket, marginally less for other 'sensible' gear combinations, even if you have not 'lubed' in a while. (The problem with studies on this is that they also include 'silly' gear combinations such as small sprocket and small chainring where the hideous chainline makes for an inefficient system, giving a wider efficiency range than is realistic). No hub gear system can improve on derailleur efficiency levels and the NuVinci FAQ side-steps giving any useful figures, preferring to make comparisons with existing hub gear systems, for which 92% is roughly ball-park. Personally I could contend with that on rides through town where gears are for getting up to speed but not for sustained hill climbing where 5% loss would mean 5% slower.
Weight is another area where the derailleur rules supreme. At the moment the NuVinci hub is relatively heavy - I think the latest systems are 1.5Kg heavier than an average derailleur setup. In my opinion weight really does matter on hills in a way that it does not if riding on the flat. I frequently pick up 2 litres of milk at the bottom of the hill where I live and it does make an appreciable, albeit not show-stopping difference to how I attack the hill.
Variable range gears. Personally I have no problem shifting gears on a 9 speed sprocket, thanks to the wonders of 'Hyperglide'. I also find that there are enough of them and I have no need for gears in between the gears that I have. For me an infinite amount of gears sounds good, but in practice I think the 'need' is over-hyped. I don't find myself changing up/down to find myself spinning furiously or plunging away completely out of sensible cadence. However, I can see how the NuVinci would help those that don't change gears that cleanly, i.e. not anticipating the need for the middle ring at the base of a hill.
Maintenance. Not a lot is needed for the NuVinci system because it is a hub gear. If you are running bullet proof tyres you won't even need to get the wheel out for punctures. However, if you did have a problem and needed to take it to the shop then they would be stumped.

To conclude, you will have extra weight, lower efficiency and a reduced range of gears. Despite the benefits of CVT with smoother shifting, reduced maintenance and not having to match your cadence to available gears, you are not going to get round the fundamentals of weight/efficiency/range.

My recommendation is that you try an electric assist bike such as one of the models made by Giant. Although they weigh a lot they are amazingly nimble and you can pedal as much as you want to on one.


Replacement Rear Axle Sizes on Vintage Bike I bought this 1990 Raleigh cheap on eBay. It had been sitting in a garage for decades and it was barely running when I picked it up. Surprisingly, given its age, most components were fine. But there was an awful clicking and grinding in the rear hub, so I took it apart and the axle and cones were coated in dirt and grime. (And being fairly new at this, I might have lost some ball bearings...)
More to the point: during a thorough clean and degrease, I found that the axle is heavily pitted and the threading has been badly chewed up. I can't even remove the drive-side cone – it keeps getting stuck on the last few threads and no amount of GT85 is shifting it.
The axle is beyond rescuing. But I've never bought an axle before and the measurements I've taken don't match up with what I've found online. It measures 162mm with a diameter of about 8.5mm.
Is it the case that I can't find this because it's some legacy axle size? Will a replacement axle of, say, 175mm x 9.5mm do the trick, like this one here? And will the 'default' nine 1/4" ball bearings be compatible with that?
Sorry for any stupid questions. I am fairly inexperienced with hubs.
UPDATE: It is now fixed. I removed the Shimano freewheel, and it turned out the metal shavings were from the dust cap itself. The ball bearings were apparently scraping against it. I've installed a new slightly longer axle, regreased and reassembled the hub with new ball bearings, adjusted the cones and it seems to be running very smoothly, no clicks or grinding.

If the cones are pitted, the bearing surfaces inside the hub shell may well also be damaged. As the rim is not particularly valuable, your local bike shop may be able to sell you a complete replacement rear wheel to suit the screw-on 6-speed block you have.
If you really wanted to only replace the axle, by 1990 I would expect a non-vintage hub to be using metric dimensions, so it's very likely it uses the most common size.


My Bike Like To Try and Turn Left So when I ride my bike it likes to give a little traction at times like the front wheel wants to turn left. The rim looks straight to me and i double checked it. Is this a problem with the wheel or the tire? Should I buy a new set of Tires for my bike?

I suspect your fork is bent.

Ride straight through a puddle and then leave tracks on dry concrete.  Your back tyre track should be superimposed on top of your front track.  If they follow different lines, your fork/frame is bent.

Use your hand throught the front rim, and by feel hold that in line with the downtube of the frame.  Then look down from above - the front wheel should be straight out the front.  If its not straight, the fork/frame is bent.

Look for corrosion and paint cracks/flakes on the top tube about 1" back from the frontmost weld.  If there's a clear ring of damage here, the fork is bent.

Can you ride hands free normally, but not on this bike?  Fork is bent.

Is a hard front-wheel brake really terrible?   Feels like you're going to be pushed sideways by wind whenever you do a hard front-brake?   Fork is bent.

Take the fork off completely. and look down the side of the steerer tube.   The two tines must curve forward from the crown.... they must NOT go backwards and then sweep forwards... if they do then the fork is bent.

Recovery - Steel forks can generally be tweaked to be better by careful slow bending with a vice and a pipe.  If its an alloy or carbon fork its probably beyond saving, but there are carbon specialists who may be able to advise.


Good Brands for Front Pannier Rack on Suspension Forks I've heard people talk a lot about Old Man Mountain racks. What other options are there? Roughly speaking, in your experience, how do they compare?

I'm specifically interested in this for touring but that probably goes without saying given the product.

I have a set of ortlieb front runner bags. so i just need the racks to attach them over mount bike suspension forks.

Get the rack first or get them together.  You need the panniers to attach solid.  Not all racks have the same places to attach.  I have Surly Ortleib combo but that is like $200.

An over the top design like this gives you more storage.  And you could lash some stuff and maybe skip the panniers. Those two little tabs on the bottom are nice for lashing.

SurlyRack
Give yourself an hour or two to install.  Lots spacers and lots of positions.

And on a fork look for threads at the bottom of the fork and mid fork. That bike also has threads on the inside for another attachment point but don't worry about that.  Go to the gallery.
Vaya


What skills/drills should I learn to descend faster and more confidently? (for mountain biking) I've ridden road and mountain bikes for years, and this is my first year riding as a part of a team (and actually doing races).  I've been stuck at nearly the same level of skill when descending and would like to improve.

Sure, there are some books I can read, but some are dated, and who has time to read a whole book?  (said only partially tongue in cheek)

Vague tips like, "ride with faster riders" are not needed - I ride with fast riders, and on the descents they're immediately gapping me at the first switchback.

I happen to be one of those who attract new riders into the sport, and have given the basic training to many people. Here is a brief of what I try to teach them:

Riding position
Be ready to react
Have your bike properly tuned/fitted
Scan the terrain(Look forward)
Use a proper braking technique
Never get to the extremes
Grow progressively
The most important: never stop trying/practicing!

The attack position

The position that works best for me is slightly raised from your seat, knees bent, lowered torso with elbows bent. Feet at the same height with the dominant foot on front.

Ready to react: Your hands should be firmly gripping your handlebar, but not tense. One or two fingers ready to activate brakes. Choose the fingers you want on the bar based on whether you get the best grip. It is a little more important to control the handlebars than to freak-ly squeezing the brakes all the time. This is critical over rock or roots sections that shake the bike in all directions. You need to hold those bars captain!

Besides this, your elbows and knees should be slightly bent at all times, giving you chance to extend or contract them as needed, so you absorb terrain irregularities as you pass them over. It is like moving the bike around you (up/down, front/rear, right/left). This is why I do not recommend to sit way back arms fully stretched: In this position you have no freedom steer or to lower the bike while entering a hole or a "step down". An easy way of thinking is this: Your arms and legs are "your" suspension, you want to be positioned rather in the middle of its travel.

Properly tuned

You should tune your bike as best as possible. This includes brakes and suspension (if any). Your brakes should be at best performing shape. This is a whole complete subject, so I wont go deeper on this, but basically, they must have won your confidence. The levers should be placed where you can be more effective to apply the brakes. The distance between the brake lever clamp and the handlebar grip should allow you to actuate the lever with the index finger, the middle finger or both. The "reach" is how far is the lever from the grip when brakes are nor being applied. This distance should make comfortable for you to grab the lever, not too far that it is difficult, not to close your fingers get tangled with it. Also, when you apply the brakes, the lever should go down to the position where your fingers feel stronger doing so.

The suspension should be properly adjusted too. The two main adjustments are preload and rebound speed. Preload is how "stiff" is the suspension and it determines "sag" Sag is how deep the suspension travels on rider weight. A proper amount of sag allows the wheels to travel down when required. When you have too little sag your tire looses contact with the ground too easily and you loose control. Too much sag makes the suspension makes it easy to bottom down, hitting the far end of the suspension travel. This may also lead to loss of control or another failures.

The rebound speed is how fast the shock absorber returns after hitting an obstacle. too fast and the bike will feel shaky (you'll feel no confidence) and maybe it will bounce off the ground loosing traction. Too slow and it will feel like getting stuck after a bump, effectively it will not be ready for the next bump if it comes too quickly. The correct intermediate position depends on your riding style and the particular terrain characteristics.

There are other adjustments that can be made, but they vary a lot model to model, brand to brand, so the best approach is to refer to the user's manual.

Scan the terrain

Look forward, never look down to the tire. The faster you want to go, the further up the trail you must look. Scan the terrain and look for the best line. Choose areas where you have more traction, or surfaces were is better/safer to brake. Dry solid rock or compact ground are commonly good options. There is a saying that the bike will go wherever you are looking at, so, focus on your route, choose where you want to go and stay there! It is common for a rider to stare at that rock sticking out, having fear of it, and... crashing into it. Avoid that behavior, don't stare at obstacles, but trace your path around or over it, and focus in that.

Braking technique

The most important skill regarding brakes (IMHO) is knowing when NOT to apply them. Braking is instinctive, as soon as you feel danger, you'll squeeze the brakes. But there are a lot of situations where it's best not to. First of all, never squeeze the levers quick and hard: this makes you lock up your tires and loose traction. You have to be gentle. Usually you have to release your brakes when going over wet roots, slippery rocks, etc. Specially you should release your front brake just before hitting a rock or a hole, so it will be free to roll over the obstacle and thus avoid being tipped over the bars.

I recommend to use BOTH brakes at the same time. You'll find a lot of divergent opinions about this but, I've found that each brake serves a purpose. The rear brake alone can slow you down just a bit,  but it tends to straighten the bike while over slippery surfaces or loose sand/gravel, a little like the rudder on a plane. The front brake can stop you down, but it tends to trow you to the front. It is vital to learn to brake without locking up the wheels, specially during a turn. If you are focused on where you are headed, it is more dangerous to over-brake than to brake a little less. It is also important not to hold the brakes all the way down, thus avoiding overheating, which can lead to brake failure.

Never get to the extremes

Never adopt extreme postures. Not to far back, not to low. I made such mistakes at my beginnings, but I had to correct those. Stretching to be too far back lessen your ability to maneuver. Using the seat too low for "improved stability" also puts your legs in an awkward position that does not let you negotiate ups and downs. While going downhill over the roughest section you should be off the saddle to avoid hitting your spine anyway.

Grow progressively

Never try too hard to get up to your buddy's riding level, do not take risks that are beyond you skills. Go a little at a time. Practice a lot. Find the way of practicing the obstacles over and over. Grow in technique before you grow in speed. Each kind of obstacle requires specific movements, as you learn them, you need to build "muscular memory" before taking it to another level, so be patient, but never stop trying/practicing. Be humble and practice even what you feel you've mastered. When you conquer an obstacle/jump/drop etc. for the first time, try to go back and do it again, and again, and again...

You may have already built skills in some of these areas, but each one of these points has way more to discuss about. I'll be happy to go deeper in any subject if I find questions directed more specifically towards any of them. My credentials: I am a cross country and downhill rider with a few podium positions at local DH races ;) .


Can I lace a 36 hole hub to 48 hole rim? I'm trying to install a 3 speed, 36 spoke hub into my 48 spoke rim.

I want to try and retain the larger wheel if possible instead of downsizing to a 29" tire. I'm getting mixed information that it will or will not work.

Can you help me in any way? I read where someone was lacing 12 spokes in a radial set up but the lacing and location of the remaining spokes was very misleading.

Is this possible?

You do not want radial spoke pattern on a rear wheel - that's not good for power transmission or for braking.

You have two options.

Lace the wheel three-cross like normal, but leave every 4th hole empty.  Downside is this will give a terrible lacing pattern, and you may need to buy a mix of longer and shorter spokes to do it half-decent.  Simply threadding the nipples on further or less, may work for some spokes, but there will be insufficient thread engagement on some spokes.

Surprisingly, a set of spokes costs more than a rim, so there's no cost saving.

And this will build a wheel that is not as strong as a properly spaced 36 spoke rim.
Buy the right rim and do it properly.  A 36 hole rim would be much better, and will only use two lengths of spoke (longer on left, slightly shorter on the right.)

Your suggestion of radial might have been related to a "half radial" lacing pattern like this one:

However notice that there are still the same number of spokes to holes.  The 18 spokes on the left side will be shorter so you have to buy 18 shorter spokes.  It looks like this fully done:

Notice the spokes are laid out evenly spaced still?

Further info here  http://www.sheldonbrown.com/wheelbuild.html#half-radial

Finally you might have been thinking about properly engineered racing wheels like this one:

These have been properly engineered to work with 2 spokes from the drive side and one on the non-drive side (left side)  You can't get the same effect by simply missing out spoke holes.


Tweaking a Giant TCX Advanced I'm planning to buy a TCX Advanced SX, this one:
https://www.giant-bicycles.com/us/tcx-advanced-sx-2017

All is cool, I simply would like a 10/42 instead of the stock SRAM 11/42. What is the less expensive way to get about it? Can I simply swap the 11t for a 10t?

Thanks!!

Changing the front chain ring to a 40t is easy and requires only to swap out one SRAM part for another.
A 10t sprocket is too small for a regular freehub. A special hub body that is compatible with SRAM XD cassettes is needed.
There are many hubs that allow you to swap the driver body. For example, the DT 350 hubs on my bike can be converted to XD standard with a part that costs about €40.
That may or may not be the case for the hubs in Giant's PX wheels. AFAIK these are, or were, available for mountain bikes with XD hubs as well. I couldn't find anything in a brief search on the web however. Perhaps I simply confused something.
If you plan to replace the stock PX wheelset, which isn't all that great anyway, it will be an easy conversion to a XD driver. Then you could mount any SRAM XG 11 speed cassette. A 10-42 XG-1150, for instance.
alternatives
As Criggie remarked, you may consider buying a bike that fits your specs better. A similar Canyon Inflite has a 40t chainring, and DT380 hubs. For these a switch to a XD driver is easy. Otherwise the specs and geometry are very similar.
If you get a 44t chain ring at the front, you will have the same transmition ratio to a 11t sprocket as with a 40t to a 10t. (A Focus Mares, for example, comes with 44t and has nearly the same frame geometry.) You might then simply choose an humongous last cog. For example, up to a 11-42 cassette instead of the 11-32 that comes with the TCX (which is geared for cyclo-cross where you carry and run up slopes when it is too steep for 32/42).
A 10t cog is by principle inefficient (chord losses). In a nutshell the chain doesn't wrap properly around a circle when the radius is small compared to a link's length. Thus 40/10 is less desirable than 44/11.


Trek 6000 for a beginner I own a local brand and am hoping to shift to a new bike. I have an option to buy a Trek 6000 D. I know it is an expensive bike. I am looking to use the bike every day for about 5-30 kms. A few offroad days hopefully, but thats about it.

Wondering if this is a good idea? Your suggestions please.

Trek makes good, reliable bikes across their price range.  I have 25 of 'em in our patrol-bike "fleet" at present.
The 6000 is well-reviewed, but it is designed and delivered as an off-road machine.  It will be less than optimum when ridden on pavement.
If you were going to spend most of your time riding on pavement, then a simple change of tires would be of considerable benefit.
Not that you can't ride a mountain bike on the road, thousands do so all the time.  It's just that those knobby tires will squirm and wear rapidly, and the riding position is not the best for long stretches on the road.


Clamp width of new Shimano brake levers Can anyone measure the width of the clamp (the dimension parallel to the bar) of the new XT M8100 12 speed Shimano brake levers?

I want to know the amount of 'bar space' the clamp takes up.

The width of either the XTR M9100 or SLX M7100 levers would be fine as well.

Here you go, the Shimano XT 12s brake lever. It's roughly 17mm


Shimano Ultegra vs Shimano Sora I currently own a 2013 steel cyclocross bike that I use for daily commuting (approximately 1 hour per day). The model I have is equipped with a Shimano Sora groupset. I am considering moving to a steel road bike, and am looking at a used 2011 model with a Shimano Ultegra groupset.

Can anyone tell me whether there will be a noticeable difference moving from a Sora to an Ultegra groupset?

The cable routing is different. Ultegra is designed to allow both cables to route along the handlebar (instead of that cable sticking out the side of the brake lever like on Sora), to give you a cleaner look and less chance of the cable getting in your way.

Ultegra is higher quality than Sora. It should shift a bit better, or at least go more miles before it needs adjusting to shift perfectly again. It should last longer.

Ultegra is basically the same as Shimano's absolute top of the line (Dura Ace), except a bit heavier.

If you're shopping around and looking at any other bikes, you may also want to consider Shimano 105. 105 is basically the previous generation of Ultegra without any carbon fiber.


Does anyone know what make and model this bike is? Production year? I found this bike while cleaning up a foreclosed home. I liked it and saved it from others taking it to the recycling center. Does anyone know what make, model and possibly year that it is?

Without too much digging around I came across a 1950s Schwinn Corvette, although I don't think its a 100% identical bike it is i'm fairly sure a variant of the OPs.

Pictures can also be found here Just for image reference

If anyone has time, a whole host of Schwinn catalogues can be found here History Catalogues


Campagnolo Large Flange Pista (track) hubs I haven't any direct experience with vintage Campagnolo large flange pista/track hubs.

Can anyone tell me if there are issues with mounting a 70-80s era 5-6 speed road freewheel and using them just like any other road/race hubs?  (a freewheel with matching Italian threading, of course)

You can run a fixed cog or a single-cog BMX-style freewheel easily on a track (pista) hub, but the wheel dish is way too far out on the drive side to fit a 5 or greater freewheel cassette.

In other words there is simply just not enough room between the hub flange and the frame to support a wider cassette. Modern multi-speed hubs have the spoke flange set in further towards the center on the drive side. Track hubs do not.


Vegetable oil to oil a bike? Is vegetable oil as good as motor oil to oil a bike?

Vegetable oils tend to "polymerize", that is become sticky and solid.  Castor oil, for instance, is an excellent lubricant that was favored for racing autos and motorcycles for a long time.  The reason it never became popular for regular cars was that it also built up a lot of sticky, cruddy goo.   Racing engines are regularly torn down and rebuilt; no matter.
Not so your sedan.
The oils used in oil-based paints are usually vegetable-based as well; they tend to become quite solid after a while.

As I've noted before, lubes, especially chain lubes, seem to be a "thing" for serious cyclists.  Chain lube threads on dedicated bike forums tend to go on and on and on...
It's the engineering mentality at work.  "Maybe I can get 100 more miles out of my chain if I concoct my own special blend!"   Maybe...
Chain lubes are cheap.  They cost at most what, 10 bucks for a bottle sufficient for a year?
As well, chains are cheap.  Oh, you can spend a lot for super-deluxe items, but a good, well-made standard chain is under 20 bucks and will last most riders as long as they keep the bike if lubed and cleaned properly.

Related

"Best chain lubricant for road bikes?" Asks about the best lubricant out of conventional oils and lubricants
"Substitutes for chain lubricants" Asks about non-traditional substitutes for chain lubricant


Carrying a Carradice Camper Longflap when off the bike I'm currently considering getting a Carradice Camper Longflap saddlebag as I've heard good things about it and like the idea of being able to carry a lot of stuff in a saddle bag.  Just one thing concerns me, and I haven't been able to find out that answer elsewhere:

Is there a handle or something on the bag?  If not, is it easy to fit some sort of carrying mechanism, or is the bag meant to be just left on the bike?

Thanks in advance.

I've got the Carradice Camper Longflap with the quick release rack recommended on the website. I got a leather strap off an old leather bag which clips easily onto the leather hooks which are placed on either side of the Carradice bag. I don't know if that's what they're meant for but it works well.


I have a few questions about frame repair, seat adjustments, and rims. My bike is a Trek 1100 Aluminum Frame

My bike has a few dings and scratched in the frame, and I want to get rid of them. So I was thinking I could get a powder coat or something to get a new paint job on there. I want to cover up the dings, but also get a new color on there like  bright green. Can I do that? If so would they go over the label and somehow out one back on or would they not put one back on? What is the price for that kind of thing too?
I was looking at some new colorful rims, and some said "single speed". What does that mean on a rim?
My bike is a Trek 1100 aluminum frame, so many of the adjustments are hex wrenches/Allan wrenches. The seat is also that way. So my question is, can I somehow put the modern seat adjuster on it? Like fit the clamp on there in a way it would stay, or is the seat post a little too small to do that?

Yes, it is possible to powder coat a frame.  They most likely wouldn't put new decals on.  You can usually find replacement decals online, shouldn't be too hard.  The powder coating process is a bit involved, and probably will not be cost-effective.  But if you want to spend the money, it's definitely possible.
First, let's get this right.  You're looking at "wheels", not "rims".  Sorry to be pedantic, but the terminology does matter here.  Single speed means what it says.  It has spacing/cassette body/freewheel threads for a single speed set-up.  Sometimes this can be adjusted(at great effort) to work for multi-speed systems, but more often it can't.
Had a hard time following this at first.  I think you're talking about a seatpost clamp.  First, there's nothing "classic" about one that takes an allen wrench.  Those are a bit more secure(if your bike is locked up somewhere, people will be less likely to walk up and steal your seat), and road bikers tend to change their seat height less frequently.  There are Quick Release options available for most sizes, as long as the clamp isn't integrated into the frame.


Best frame material for Leisure I cycle less than 10kms a day but I'm a little on the heavier side as well. What would you recommend, Aluminium, steel or Carbon fiber frame (body)?

The material doesn't matter so much in this case -- the design of the frame is more important. You aren't looking to save weight on the frame or asking a lot of performance of it (e.g. you're not sprinting in the Alps).

For leisure riding, you want a relaxed riding position which is usually more upright than a racer. You can find hybrids (e.g. Specialized Sirrus/Trek 7.x/similar) made from steel/carbon fiber/aluminum (depending on how much you want to pay). Good bikes can be made from all of the materials, but, of course, a bicycle is the sum of its parts, and the more expensive ones typically come with other improvements as well (better quality wheels, shifters, nicer fork, etc.).

At least on the US market, for most people looking in the hybrid-type bicycle class, most of the bikes I'd suggest (Specialized Sirrus/Trek 7.x) tend to have aluminum frames and carbon fiber forks at just over entry level price points (with the entry level versions having aluminum forks).


Shimano Sis Bar-end Shifters on a Shimano Deore xt derailleur Rebuilding an original fisher MTB, with drop bars and bar end shifters.

I was wondering if I am going to run into any compatibility problems if I run this with a Shimano Deore Xt derailleur system.

Also I am wondering what type of chain would be best to use?

It depends on which generation of XT derailer and how many speeds your cassette is.

For the last generation of 9spd and earlier (RD-M772 and lesser numbers), the actuation ratio is all the same for mountain and road. So you would use SL-BS77 shifters with a 9 speed cassette, SL-BS64 for 8, etc, and the shifters won't care which derailleur they're attached to.

Shimano changed their MTB RD actuation ratio when they introduced 10-speed mountain components, and this is where the answer gets more complex. If you're using any 10-speed Shimano RD, the only choice I know of for bar end shifters (unless you use a pull adapter) are the ones made by Microshift specifically for this purpose. Road/tri bar ends such as SL-BS78 will not work because they're for the older actuation ratio. And if you're using a 10-speed XT derailer, you must use a 10-speed cassette.

Same deal for 11. If you have the 11-speed XT derailer RD-M8000, the only bar end shifter choice (again that I know of) is the one made by Microshift.

Use whatever chain your cassette is made to take.


Just decided to start commuting to work I made a bit of a boast in the office a couple of days ago when it was suggested that I ride into work, it's a 13 mile trip one way.

My boss is a bit of a MAMIL, and has cycled quite a bit, to him 13 miles is a walk in the park.

My bike is a £70 jobby from Halfords, only really used perhaps once or twice a year for going on a short bike ride with the kids.

I also have a very sedentary job and am sat at the computer 8 hours a day, I used to be fit 20 years ago as I was in the forces but since leaving, the only excercise I have done is one 10Km run (as a bet) about 8 years ago, and today I'm nursing the effects of riding 29.5 miles on a bone shaker in flip flops.

Problem is, I liked it and want to do this, initially once a week but want to build up to several times a week.

Any advice on what I should buy to make my life easier?

Before you ride, give your bike a safety check.  Its been sitting about for a while, and there could be problems you're not aware of.

The Sustrans website covers this at https://www.sustrans.org.uk/what-you-can-do/cycling/your-bike/bicycle-maintenance-made-easy/m-check-your-bike-11-steps

For things to buy/find:

Wet weather gear - You mention Halfords so its likely you're in the UK, which seems to be enjoying a riding renaissance.  But the weather's going to be wet someday.  You'll need a coat that works for wet riding.  Later you can add overtrousers or overshoes.  Personally I ride in gumboots (wellingtons) in the wet.
Helmet - Not mandatory in the UK, but still a very good idea.
Lights - again if your job hours mean riding after dark, lights are probably mandatory for you.
Spare clothes, towel, deodorant.  Either carry them with you in a waterproof bag/rack, or store them at work for a change on arrival.  Consider using your non-bike days to carry that bag to/from work for starters.
Bike security.  Its no good coming out of work and finding your bike's missing.  Even though its a cheap BSO bike, a lock will help prevent it from vanishing.  I've got access to a bike room at work - check with your MAMIL about where to park it safely.
Water bottle and bottle cage on the bike.  On a hot day you can go through a lot of water, so its easier to carry that on the bike and not on your person.   Your bike should have a couple of screw holes on the downtube, and a cheap plastic bottle cage will bolt in there with M5 screws.  Use grease.  Any convenient sized bottle will do, but poptops work best if you drink on the go.  Screw tops require you to stop for a sip.

Those are all I'd call immediate needs, and its likely you have a lot of it already (how many people in the UK don't have a waterproof jacket already ?)

If you're handy you would consider carrying pump/spare tube/levers and whatever you need to get the wheel off, for changing a flat.  You will get a puncture eventually.  Its just a part of cycling.

Depending on how old your bike is, it might benefit from new brake pads.  They dry and harden with age, and braking suffers.

If your bike has knobbly MTB tyres, consider replacing them with smoother ones when they wear thin and punctures start getting frequent, or you see canvas.

Otherwise simply keep riding.  Aim to wear your bike out and then reward yourself with a better one in a couple years.

Related - recording your rides can be of massive value over time, to see how you're getting faster.  Personally I use strava to record my commutes and rides for future comparison.   Downside of this, your MAMIL might do so as well, and it may become competitive.  Don't be put off if this happens, just use strava to record your own progress and don't compare with other people.

Seeing improvement over time is an awesome ego boost, because it never feels faster at the time.


Does the top tube typically open into the head tube? This must be a very basic question, but as it often happens with very basic questions, it is often hard to find the answer by searching.

On a modern bike with metal (welded) frame, is the interior of the top tube (and/or the down tube) accessible through the head tube? I.e does the head tube have holes in it that lead into the other attached tubes of the frame?

From what I could see on the Net, it appears that the head tube is typically a full cylindrical tube, without any holes. Is that so?

Meanwhile, it seems that I have some parts rattling inside the top tube of my bike (Specialized TriCross), which routes the rear brake cable through the top tube. I wonder how they got there, if the interior of the top tube is not accessible (aside from two fairly small cable holes/openings)

Any welded tubes are going to have holes in their ends in order to let the hot gases escape. So, yes, there is virtually always going to be a hole connecting the interior of the top tube and the head tube (along with every other tube on the bike).


I can't find my skewer that came with the trainer. Can I use my bike skewer? I have misplaced my trainer bike skewer. Can I use the one from my bike?  I am not concerned about scratches.

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

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

I should have your LBS order in something suitable


What is the second thread on the crank for? I am trying to fix the problem with my bicycle where the left crank keeps unscrewing itself. The thread on which a serrated lock nut should keep the pedal in place is conventional (clockwise to tighten).

When looking closely at both sides. There is some sort of thread on the inside of the crank cavity itself and it's not used by anything since this cycle has been bought. May anyone know what this may be for?

The lock nut is used to wedge to crank on the bottom bracket spindle.
If you open it, you should still not be able to get the crank off, at least not easily.

For square tapered bottom brackets, usually you have to use a tool called a "crank puller", which is hold in place with the outer thread.

See this article over at Sheldon Browns for details and very interesting pictures showing whats going on inside the cranks.


Help finding correct headset for Focus Izalco Max Disc I have acquired a Focus Izalco Max Disc frame and forks and am having trouble finding a headset for it. The steerer bung in the fork reads 28.6mm and it looks to have a slight taper. I have read online that it's a 1 1/8 -> 1 1/4 inch but the headset I have purchased doesn't fit (FSA no53).

The headtube of the frame measures ~42.5mm diameter at the top and ~47mm diameter at the bottom.

I tried the Cane Creek headset finder but it doesn't have my frame model in its database and can't identify any headset models that fit the dimensions I enter.

I have a feeling an FSA Orbit C-33 might be a fit but I can't find any material online to back this up aside from the fact it's one of the few tapered headsets with a 1-1/4" lower bearing.

Any ideas?

This listing has it down as an Orbit C33 SL ACB.

I can't read German beyond getting the gist, but that looks to confirm your suspicions.

I believe the SL and ACB are just the materials / tier of product and C33 is size.


How long will a battery last in a Garmin GSC 10? My relatively new Garmin GSC 10 Speed/Cadence unit has started losing connection to my Garmin 500. I'm assuming that the battery is running out, since I'm still using the original that came with it. I have done about 35 hours of riding.

So I am wondering: how long should a CR 2032 battery last?

I know this is a little subjective and will depend on ambient temperature and to a lesser extent speed and cadence for transiently illuminating the LED each pedal stroke/wheel revolution. But generally, how many hours can I expect to get from a battery?

Right now I am at 159 hours of riding time on the battery which came with my GSC-10.

Garmin's stated battery life for the GSC-10 is 1.4 years at one hour of riding per day which works out to 511 hours. (See page 51 of the Edge 500's Owner Manual)

On the interweb I've come across two different suspected causes for low battery life on the GSC-10:

Some (mostly older?) GSC-10's are susceptible to corrosion due to incomplete sealing of the circuit board inside the GSC-10. If this occurs battery life is shortened due to an internal short which causes the battery to drain more quickly than normal.
If you store your bike with either the cadence or speed magnet lined up with the sensor, the GSC-10 may not go to sleep after a short period of inactivity like it is supposed to. This seems to result in faster than normal battery drain.


Jumping - What happens if you pull your back/front brake in the air? What happens if you pull your back brake in mid air?

What happens if you pull your front brake in mid air?

Does your bike go lean forward or backward?

Someone told me you can use these techniques to control your jump.

If your wheel is spinning hard in the air, and you apply a brake hard, the rotational momentum has to go somewhere.

However your wheel is rotating forward, and stopping it will make your bike rotate so the front drops.  Often that's not what you want.

Also the time available is really small and your reaction time shortens the effective window too.

If your wheels are not spinning fast then there's no stored momentum there so applying the brakes will do nothing.

The question you didn't ask is "What happens if I land with the brakes hard-on?"   and that generally means badness if you land with any forward momentum.

The front wheel will be locked so it will either make the brake slip or it will make the tyre slip on the ground, starting a front-wheel washout.  There's also a chance your front wheel will turn sideways which will lead to a taco  or a complete OTB (Over The Bars).  Doing this is most likely to put you in hospital or worse.


Clicking noise while pedaling I have a Trek Domane S4 (carbon) that makes a random "clicking" noise while pedaling. I can feel it thru my feet, so I'm thinking its coming from the crank area, but can't seem to figure it out. I use Mtn bike shoes w/ clipless pedals, could it be the pedals?

if the clicks happen when you're pedaling hard or uphill, try tightening the pedals more.


Do Carbon Wheels Stay True Longer Than Aluminum Wheels? Does a race quality carbon wheel set stay true longer than an aluminum one (with equal abuse/mileage) ?

It seems like the properties of carbon would resist flat spots and warping better than aluminum.  Is this the case?

Also, is carbon easier to true than aluminum?  Aluminum can get bent badly and be rendered useless; does this happen with carbon or does it just crack?

Thanks

I give you the following, that you can read here:

  Talking to Jason Marsh the mechanic of Greg Minaar 2012 DH World Cup
  Champion about ENVE DH rims (which are carbon), he said that, ”Once
  you have built them, you don’t need to do anything, the spokes remain
  tight and they don’t need truing and we use a lot less through the
  year as they are stronger…”

The user in this forum reports long carbon wheel use with no need for truing, and DTSwiss also recommends the same maintenance interval for carbon and aluminium rims regarding checking if the wheels are true, which is an hint to them being similar.

The main problem with carbon, and this is also true for carbon components in general, is that despite being stronger than aluminium it is also more rigid, which means they don't respond as well to sharp impacts. Think of it as a steel vs an aluminium nail: the first one bends easily but holds the structure, while the steel one is very tough but breaks all of a sudden.

This is also said in this interview with a pro bike mechanic, that says carbon wheels are faster because you can maintain your direction better (more rigid), but have overall less durable because in an accident or impact they are more likely to require substitution. He even says that it is normal for costumers to try both types and prefer aluminum due to their compliancy and comfort.

Getting back to your question, I would say that due to the compliancy and flexibility of aluminium they hold dents and impacts better, as these are just killers for carbon rims. As the mechanic in the interview says, to which I agree, Carbon wheels are an expensive luxury. I personally would easily buy carbon components for my bike with the exception of the wheels, as these components in particular are very likely to have to sustain high impacts due to low tyre pressure, trying to go up a sidewalk or a bad measured bunny hop. We have all been there :)

Edit: You guys are right, I just threw it here :( I will try to improve.


What if both wheels were powered by pedalling? Only the rear wheel of a bike is connected to the drivetrain in order to propel the bike forward. I assume the choice of rear wheel instead of the front wheel is for stability (e.g. avoiding 'fishtailing' and other problems).
However, would there be any potential benefits if, somehow, both wheels were connected to the crankset so that the input power could be shared between the wheels? (This hypothetical system need not use a chain – c.f. shaft-driven drivetrains like CeramicSpeed.)
One advantage of a two-wheel drive system is that there could be improved grip and control on uneven, off-road terrain but the disadvantages probably outweigh this benefit.
The obvious disadvantage is you would be powering two wheels instead of one (so the rotational inertia would double?). You would also have to deal with the fact that you have to steer with the front wheel too!
I doubt any sort of bike like this has been made* / will be made in the future, but it's interesting nonetheless to imagine what this could be like...
*EDIT: As the comments have pointed out, they do actually exist.

Many two wheel drive mountain bikes exist. Here's one article advertising a new one:

There’s been no shortage of attempts to build a workable two wheel
drive bicycle over the years, but this latest effort from Double of
Japan looks like one of the most compelling yet.

https://www.bikeradar.com/news/this-is-a-two-wheel-drive-bike-done-right-sort-of/
They do offer better traction in some situations but I've never seen one with a limited slip differential between front and rear, which means they need a freewheel for each wheel to avoid stressing the drivetrain (you really don't want one wheel pushing backwards!). The extra weight and drivetrain complexity is always there but the extra traction is only useful very occasionally.
The other problem chain driven ones have is limited steering range (see the one in the article above). That's not a problem on FWD speedbikes where the steering range is limited by the fairing (often to +/- 5 degrees or so), but for technical mountain biking it's a huge issue. I commonly steer +/- 90 degrees in technical sections, and even on normal trail climbs half that. But getting a +/-45 degree swing out of a universal or CV joint is hard to impossible.
There are also flexible cable drives. Those trade more steering movement for more losses and generally shorter service life (ie, the only one I tried broke, luckily not when I was riding it). With a flexible shaft some wind-up is actually useful, as it gives a bounce in the drive to help you over large bumps. But it's disconcerting when riding and overall burns effort from the rider to counter the wind-up all the time while helping occasionally.
A rigid shaft drive could in theory have a rotating linkage with 180 degrees of steering freedom, but would be quite complex to build. It would also need a telescoping section if there was front suspension, and likely significant gearing to reduce the shaft size (and the torque on the sliding section as well as on the steering).


How do you find the right saddle for road biking? I bought a Cube Attain GTRC disc, a great bike apart from the saddle, which is quite chunky and square.

I would like to find a better one.  Tips for saddle sizing for road biking?

Long saddle versus short
Cut out or not
thin versus thick
measurement of sit bones? how?
material?
brands?
length of ride

I once went to the cycle show and sat on a special seat that displaced blue gel and showed the shape of my arse. Is this recommended? Not sure if I will find these in IKEA though.

It is very much like with shoes: very personal. You look for one until you find it and then you use the same model for as long as possible.

Or, one can use service of a tailor, or in this case, bike fit expert, for a price. Sit bones measurement is one of the most affordable things, as a simple cardboard can be used for that.

For complex cases, a custom saddle can be molded specially for you. See an article by Lennard Zinn at VeloNews.


Frame lock that can lock without key inserted Does a frame/wheel lock that can be locked without the key being inserted exist? And if so, how secure is the lock itself (I heard that this style of locks that can be locked without the key inside are more susceptible to picking than normal style locks)?

These locks are variously named ring locks, cafe locks, O locks and defenders.

Update: There is another style of lock that is similar to the one picture above, but it has a straight locking bar instead of curved one. This type can be locked without the key inside, but it's not as easy to close and open due to the bar not being curved.

You should note that non-key-retaining locks that don't involve a separate lock-actuating lever are susceptible to shimming.

Before buying a lock, you should always google or YouTube search to see if your lock can be easily shimmed or bypassed.

Ps I would not worry too much about picking unless it's a tubular lock, as most thieves will prefer to use physical force (cutters, grinder) as they are much faster (5-30 seconds) than picking (1-5 minutes in ideal circumstances; 3-20 in non-ideal).


Why not have the gears inside the bottom bracket? Looking into an IGH it seems the biggest disadvantage is having a huge amount of rotating mass. I've seen one handmade bike where the IGH sits above the bracket, inside a carbon fibre shroud around the place some bikes have rear suspension. There are two chains, one driving the IGH and another to drive the rear wheel.

Why not have an internally geared bottom bracket where the cranks drive the input shaft and the crank ring rotates at a ratio selectable by the gear lever?

Then the rear wheel could have a single drive wheel driven by a chain or belt and a lightweight hub just solid enough to mount the spokes and disc. Then you could have mud-free gearing while reducing rotating mass even below what you have with a conventional cassette... and given that you have thrown out the bottom bracket the overall weight gain would be less.

Quite a job for the home builder to adapt an existing hub I guess but it should be possible.

The lack of popularity is partially because it's a solution in need of a problem.  The effect of rotating mass in general is generally overstated when considering the total energy that goes into cycling, and mass near the axle has even less of an effect.  You can work out the math here.

The main advantage comes when considering unsprung mass on full-suspension bikes, where having weight on the rider's side of the suspension can improve the handling and response of the bike. This is why inroads have been made in downhill circles.


Restoring/modernizing an old cheap(ish) bike tl;dr;? Just see bullet points below...

My mom recently gave my wife her old Raleigh Horizon bike.  She must have gotten it around the year 1990, and there's no way she spent much on it (she's kinda cheap).

I don't know much about bike's - I mean I rode them every day of my life as a kid, but I never really got into the nitty gritty details of a repair or upgrade.  My plan with this Raleigh, is to repaint it, which shouldn't be a problem.  However, I also wanted to replace the cables and shifters if possible since it's disassembled already.  Possibly the cassettes, too.

Finding information on an old cheapo bike like this is kinda hard.  Most Youtube videos are for hardcore guys who are all about their $1000+ bikes (probably you guys lol).

I basically want to get my wife a bike that works well but isn't going to cost me more than $100 (USD).  I have the bike, it technically works, but the chain does slip off when shifting a lot and these shifters need to pressed pretty hard to make them do anything.  They're also slightly rusted.

I've already disassembled the entire thing to prepare it to be painted.  I just want to reassemble it with some new parts to make it better...

My questions are:

Are brake cables and shift cables the same? On Amazon I see most are sold as "shift" or "brake" cables but they seem the same to me...
What type of cables would an older bike like this need if I wanted to replace them (and maybe upgrade, if not too expensive)?
Can you recommend a set of sprockets (or cassettes) that would allow the shifting to work better.  Nothing extreme, just simple but decent ones... if that's a thing :)
Can you recommend a set of shifters?
Is there any other inexpensive upgrade that you might recommend?

Thank you!  Sorry for the noob questions

UPDATE: updated the terminology to be correct (I think).  Thanks @ojs :)

There's a lot of questions in here. My suggestion is to read through https://www.parktool.com/blog/repair-help and http://sheldonbrown.com/ instead of asking a separate question for everything.

Brake cables are thicker than shift cables, and the outer cables are constructed differently. There are different variants of the cable ends for both, you need the correct one. "An older bike like this" is not enough information to guess which one you need, there are a lot of different old bikes sold as "Raleigh Horizon".
We don't really do product recomendations because they tend to be location-specific and information gets out of date. Once again, we need more information to tell which cassette or freewheel fits your bike.
The above applies for shifters, which I guess you mean by "shift nobs".
If the tires and brake pads are original, replacing them with new decent quality ones is a huge improvement.

What you didn't ask but I'd recommend anyway: lubricate the chain and cables and adjust the gears before buying anything. The shifters are probably stuck because of old, dirty grease, and cleaning them with WD-40, CRC 5-56 or similar should help.

Update after pictures: This style of shift lever can be completely disassembled and greased. If you want to replace the sprockets, what you need is a 6-speed freewheel and appropriate tool for removing the old one. New one can be screwed on by hand. Newer freewheels have teeth shaped for easier shifting, so upgrading may improve shifting. If you change to a new freewheel, you need to replace the old chain too, because it has worn together with the old freewheel. The correct cables are MTB-style for brakes and road-style for shifting.


A bike for city commute - disc brakes, bar-end shifters, tires I'm planning on buying a bike for city commute.

My commute to work is approximately 12km (7.5 miles) one way.  I live in Vancouver which means:

I'll be riding in rainy weather frequently.
I'll be going up and down hills.
I'll be going through lots of intersections (meaning lots of stopping and starting again).

And I'll be commuting mostly during the rush hour.

Here are a few questions:

Since I'll be riding in rainy weather: a) should I get a bike that has disc brakes?  I read somewhere that they behave better than rim brakes. b) should I get a bike that has hydraulic vs wire brakes?
Since I'll be going up and down hills, I'll be changing gears.  Are bar-end shifters the best choice for this type of riding?  Or are they meant for rides where the gears don't change often.
What kind of tires should I be looking for?  I figure (intuitively) thinner tires are faster, but since I'll be riding in rainy weather should I opt for thicker tires (more surface area)?

Is there any other thing I should be looking into?

For a city commuter bike, don't bother with disk brakes - go for simple rim brakes. You'll want the reliability over all else. You don't need disks for most types of road cycling, as the limiting factor for grip is likely to be your tyre anyway.

As regards shifters, go with whatever is comfortable for you. I like the combination of brakes and gear levers in the same unit, as you don't need to take your hands off the brakes to change gear. This is very useful in traffic.

I would also recommend touring tyres - offroad tyres lose too much power through rolling resistance, but you want tyres wide enough that you have some comfort and puncture resistance. You could also look into self sealing tyres.


campagnolo wheel on shimano or sram drivetrain? I have a road wheel that has Campagnolo splined hub and 10 speed cassette.  I'd like to know if anyone has any experience running a Campy wheel on Shimano/Sram drive train?  I know the measurements of the cassette sprockets are a bit off but wondering if you can get acceptable shifting performance.

I don't have experience with that exact setup. I have used a Shimano-9 wheel on a Campy-9 drivetrain, and it more or less works. With the addition of a shiftmate, you can mechanically compensate for the differences in cable pull. It's a little fussy getting set up right, but it does work.

Also, (not that you asked, just in case someone else finds this thread in the future), Mavic sells a cassette that fits Shimano splines but has Campy-10 spacing, for use on a Campy drivetrain. I'm not aware of a cassette that does the reverse, but it wouldn't surprise me if one is out there.


Can we use low-end front derailleur with an 11 speed crankset? Can we use a low-end front derailleur like Shimano Tourney 2x with an 11 speed 2x Shimano (105, Ultegra or Dura-ace) crankset? If not, how low can I go?

Just needs confirmation base from this link I've read.

Compatibility [05] Front derailleurs

Any 2x front shifter has only two or three clicks and as long as the cable pull isn't wildly out of spec an X speed derailleur will work with an 11 speed crankset. If you have just a double in front the key thing is that the cage curvature match the size of the large chainring and you can mount the derailluer with the appropriate clearance (roughly 3mm between tooth tip and derailluer cage). I have successfully shifted 11 speed double chainrings in in 50/34, 46/30 and 38/22 with 9 speed front derailleurs and Campy 10 speed brifters. Having a chain catcher like the K-edge one helps a lot.

Triples are more fussy when it comes to matching derailluer cage and shifters.

It's almost never a question of will it work, but will it work smoothly enough for you. Mix and matching components will always require a bit more fiddling and likely will not ever work as smoothly as fully matched high end components. But it's just a bike, enjoy the ability to hack and bodge things while you can.


What model is this old child’s bike? I found this in my grandfathers garage. He said it was in the garbage like 15 years ago. I don’t know but hope it’s something cool and antique. I am crossing my fingers.

That’s a Rollfast Skoot, probably late 60s or early 70s.

If you were hoping it’s valuable, in its current condition it’s probably not worth very much. There’s a nearly identical but fully restored one on eBay right now. Keep an eye on that and see if it sells for asking price or not. Then you can decide if you want to put the time and money into restoring it.


Newer Shimano R7000 pedals having smaller contact area than older R5800? I was comparing Shimano PD-5800 and the newer PR-7000 SPD-SL pedals. Judging from the metal contact plate on them, the newer model seems to have a far smaller contact surface area.

Is this correct judgment or are the metal plates only part of contact area?

PD-5800 SPD-SL pedals-

Newer PD-7000 SPD-SL pedals-

The metal plates are only part of the contact area. In my opinion the 5700 pedals are SO good, you can’t go wrong with either model.   If cost is a factor you will get years of excellent performance and durability from both.

There is a smaller rectangular raised section between the metal contact plates that also contacts the cleats.


Is this crank usable or should it be replaced? I've been suffering from weird noises while pedalling for a couple of weeks.  Noise has been isolated to the left foot, its definitely not the right side.

After an inspection revealed no cracks or other badness,  I pulled the left crank off with a puller.

  The lip around the presser on the right hand side of the image?  That's compressed outward, and once I got the crank off the pusher of the puller was wedged in the taper.

The other two sides are only lightly marked.  The two sides pictured are the worst damage.

The crank was cleaned and refitted with a light coating of copper slip on the facing surfaces and it seems to be functioning fine.  But

Question: Is this crank safe?  Or is it vulnerable to further damage?

It's hard to tell if it will be OK, and it will depend on how heavy you are and how much pedaling torque you can produce.

The main problem you are going to face is not the reduction in area of the taper surface, but that the puller will have pushed the edges of the gouged area up, so that the crank will not fit quite properly on the spindle taper. Because of this you may find that you have problems with the crank staying on the spindle.

If you feel inside the taper with a finger tip (my pinkie fits inside a crank taper, and I have fairly big hands) you will feel an raised edge or 'burr' of material around the gouged area. You will want to very carefully file that off with a fine, flat needle file. It will only take a few light strokes to remove it.

When you re-install the crank, torque the retaining bolt up to the maximum allowed. Do a test ride and check that the crank is staying in place. Check the crank regularly when you ride after that. Hopefully it will stay in place.


Convert front wheel back to fixed nut My quick release rattles so how can I convert back to a fixed nut front axle?

This is achievable, but you're using a big hammer to fix a potentially small problem.

If your wheel has a Quick Release axle like pictured on the right side here

Simply removing the QR Skewer and slapping two nuts on the outside is a recipe for disaster.  There is not enough thread going outside the fork's dropouts to hold a nut.  There's 100mm (4 inches) of axle inside the wheel, and a QR only lets 2-3mm (not a lot) poke out either side.  You need at least as many threads out each side as there are threads in your new wheel nuts.

Another comparison

So you need a complete new front axle, 2x cone nuts, and 2x wheel nuts for the outside.  Its worth replacing the bearings at this time too, because they're cheap and may as well.

There are some slightly-custom tools needed too - picture shows a pair of thin cone spanners, which are only about 2mm thick.  A normal spanner won't fit on the cone nut flats to hold it while adjusting the bearings.

If your axle looks like this then its a Through Axle ("thru axle") and you're on a fairly modern bike.  Reverting to nutted wheel axle will require adapters that are custom to your frame/through axle design, and there are too many variations to explain here.


What are the benefits of purchasing a complete bike from a respectable brand? (Road cycling) I've been into cycling (almost) my whole life. I've been riding BMX for over 20 years and since 5-6 years I've been doing a lot of road cycling. I ride contests, crits, TT's,...

I've been looking to get a new road bike for some time now. I outlined some requirements that this bike should have. With that out of the way I started looking around for my options, there are a wide variety of bikes that handle my needs. But coming from BMX I am used to building my bikes from the ground up. Changing parts as they broke, building completely new setups,... The only complete setup I ever got was the bike that got me started.

Apart from price, what are the benefits of purchasing a complete bike from a respectable brand? Canyon Aeroad CF SLX 9.0 DI2 for example, this bike meets the requirements and falls neatly in my budget. If I would start building my bike it would end up parts wise like the Aeroad.

What not to take into consideration: I am technically able to build and maintain most bikes on my own. This should not be an issue.

Warranty - buying one bike from one supplier means the whole thing is under warranty.  New bike frames may have anything from one year to lifetime warranty, but often have a rider about "must be assembled by an authorised and qualified bike shop"

Integration - all the parts will physically fit into the frame quite well.  Stuff like internally routed cabling simply works better when the parts are all specified on the one build.

Compatibility - Its not your problem to make sure that a front mech and a chainring set match up.  A complete bike will work from new as it is supposed to with no fiddling and fettling.

Set price - a complete bike has a set cost.  A build has an unknown end cost because you may not find the parts you need at a fair price.  On the other side, the parts you need might be in your possession already so have zero net cost.

Timeliness - you want to ride your new bike, not spend time assembling and troubleshooting it.

Suggestion : Since you can afford a high-level bike like a canyon, and time is valuable, just buy it and ride it and spend the time on maintenance.


Stress on front fork from car transport It's often easier to transport a bike in the back seat of a car with the front wheel off, rather than setting up the bike rack. I've noticed that, due to the way the car seats are built, there's often unequal stress on the fork. Do I need to be concerned with this, over the course of a few hours on the road, or is this a nonissue?

The bike I most often transport like this has a steel fork, although I have a bike with an aluminum fork I put in the back seat every so often.

How much unusual stress are you talking about?  The weight of the bike all on one leg of the fork?  Or the weight of a really large person leaning back against the fork?

If it's just the weight of the bike leaning "wrong" on the fork, I wouldn't worry about it.  That fork leg is built to handle a lot more stress than that in normal riding.

If it's worrying you, you could always pick up a cheap hub and quick-release skewer and put that into the front fork when carrying the bike in the car like that.  That way the stresses on the fork would be shared on both sides and much more match up what happens when you're riding.


When should I use lockout feature on my fork? I have a trekking bike with a 63mm fork which has a lockout feature enabling the control of the suspension.

Can you explain when should I lock the fork, in what position and why?

One obvious example would be when climbing hills, one should lock the fork in minimum suspension (almost no suspension, the fork is stiff/hard as if there is no suspension at all). The reason is to prevent that the part of the energy is lost on the amortization...

But, what are other examples? What should one do when going down the hill? Or going really fast?

Anytime the fork bob is robbing you of power. That can include flats, sprints, climbing... Best advice is probably to try it out on all the terrains you ride and decide where it works and where it doesn't.


Makeshift car rack for a short drive? I need to transport a bicycle down a highway. It'll be a ten-minute drive. The bike won't fit inside the car, though. Is there any way to mount/tie the bike to it?
Context: I'm going to be taking a public bikeshare bicycle to a car rental place, and then I need to transport the bicycle to the nearest bike share station. So I can't modify either the bike or the car.

It sounds like one of these situations where walking, at the sustained pace of 3 mi/h - 4.8 km/h will do the job.
Think about the time you will need to set-up the bike to fit in the car. Probably you cannot remove the front wheel from the bicycle, because they use special lock to avoid theft.
However, you face two solutions:

If you are fit to cycle, you are fit to walk or even run to the rental car agency. It seems weird, but hey, bike rental were a weird things until 5/10 years ago!
the bike will fit inside the car, at least partially. keep it in place with bungee cords, and use bungee cords to keep the bicycle in place, as well as those "flat section ropes with metal hook used to move furnitures" to keep the lid partially closed and the bike inside.

Take into account that the car will possibly prevent your gearbox to shift on a gear >2 with the trunk open.
Every car has at least a couple of hooks inside the trunks.
What car are you renting? a Smart or a SUV? what bicycle is the bicycle? 20 inches wheels or 28 inches wheels?


What differs between the Cervelo S5 and S5VWD Looking at the Cervelo S5 series there are two different models but the Cervelo page offers no mention of what differences are.. could someone enlighten me? Looking just at the framesets is there a difference?

They are different frames, with the VWD being lighter than the normal one. It is claimed that other properties (stiffness, comfort, shape) are the same, though.

This thread, in particular the post by em3, point to the following links from Cervelo: a,b.


belt vs chain for what matters performance only Let's set apart all pros/cons of chains vs belts, like: ease of maintenance, need of a custom frame, cost, spare part availability, all of that: nope.
This question is very focusing only on performance.

I read several reviews, one the most interesting being this one. They measure the performance of the two systems with this tool:

and they come out concluding that:

  a conventional chain drive consumes 2.92 watts on average, while the
  belt eats up 3.93 watts. Although the difference is just 1 watt – not
  enough for most people to care – this works out as a substantial 34.6
  percent.

But unfortunately, also:

  That data does have some caveats, though. While the chain drive was
  tensioned to a typical 2lb, Gates recommends a much higher preload
  tension of 85lb in order to prevent slippage under load.

So, overall it is to be expected that the old chain is going to be more efficient, according to that. But let's not forget that the belt drive system, though less efficient, is also way lighter!

This also affects performance.

In fact, to this article shows how "the entire belt drive system consisting of a belt and front and rear sprockets weighs nearly half of a standard chain", which is a massive improvement in weight.

So in short:
Would the weight gain compensate for the performance loss?

First things first: A belt is probably slightly less efficient than a properly installed clean chain. The test you link already indicates that. Probably with the tension Gates requires you'll loose a bit more power.

On to your question:

The chain is 200 grams heavier than the belt, of course with the chain you get gears, which you don't get with a belt unless you also install an internally geared hub, which changes the weight of the entire drivetrain heavily the other way, but lets disregard that for now. You loose 200 grams, and you loose 1 watt. From how big a pool do you take that watt? Just to grab something, take a number from here for a cyclist doing a timetrial of 10 miles in 30 minutes: 157 watt.

So this means 1 watt is a loss of about 0.66% for a reasonably fit recreational cyclist.

Given that a reasonably fit recreational cyclist weighs about 80kgs, has a bike of 10kgs, and is carrying 3kg of clothing, gear and filled waterbottles, the 200grams (0.2kg) you save translates to about 0.22% weight loss. So we can already conclude that the weight gain would never compensate for the efficiency loss.

However, when going at any sort of speed, weight is not the factor holding you back, air resistance is. So unless you only bike up the steepest parts of HC climbs in your riding the reality is that the weight loss from a belt drive will never compensate for the efficiency loss.

As far as I can see, the reasons for switching to a belt drive (probably combined with something like a rohloff speedhub) are:

Less maintenance
Less dirt sticking to all the oily bits (belt stays clean longer)
Efficiency degrades less over time between cleaning intervals (meaning a dirty chain is a lot less efficient than a dirty belt)

As a year-round bicycle commuter I can tell you that without a doubt a belt-drive combined with an internally geared hub is way more efficient with my time than a chain could ever be. I loose maybe a few seconds over my 15km (one way) commute (if that) but I gain hours by only having to hose my bike down every other week rather than cleaning and re-oiling my entire drivetrain every few days.


Hydraulic mtb-style brake lever on drop handlebars tl;dr

Does anyone know of an existing hydraulic brake lever (eg (like this)) that can clamp on a 31.8mm bar or can anyone think of a way I can hack/bodge/modify one?

I'm thinking similar to how CX bikes do it with cables except I want it not inline (separate brake) and hydraulic

Context:

I only have a right hand
I'm building a road bike with drop handlebars and a hydraulic disk brake (Shimano r8070, right-side, front brake).
I have been happy with a single brake for 20+ years but since having kids I feel like a second, backup, brake would be wise

Out of the box solutions welcome!

Shimano's new GRX line include "sub-levers" that seem to fit your needs.

They are meant to be mounted on the tops of drop bars near the stem and run along the same hydraulic line as your main hydraulic lever/shifter. The product ID I believe you need would be BL-RX812-R (or -L if the left was desired)

https://bike.shimano.com/en-EU/product/component/grx-11-speed/BL-RX812-R.html


What is the use of GPS/Elevation on Bike computers Can any one let me know what is the exact use of GPS/Elevation on Bike computers
(EDGE 500,510 or TIMEX 2.0)?

I ride with a SIGMA BC 16.12 (with CADENCE) and POLAR HRM. I check my elevation using STRAVA.

One reason that i can think of is

    all these data collated onto one graph for post ride analysis.

Apart from the above reason, is there any advantage of GPS/Elevation detail during the ride?

Thanks

Ever had that "this has to.... be the top.... oh sh$%.... it's a crest.... there's more...." feeling. Knowing altitude lets you pace your climb and arrive the the top without over (or under) doing it.

Imagine riding flat roads without knowing speed or distance - it can be done, but to maximize training effort or race performance you need to know speed/distance on the flat and altitude/climb rate on the hills.


Effect of Rear Derailleur Cage Length What effect does the length of the cage on a rear derailleur have on bike setup/shifting?

The  cage length is what determines the rear dérailleur’s total capacity. The total capacity equates to how much slack chain the dérailleur can handle. Sheldon calculates it as

(number of teeth on largest rear sprocket - number of teeth on smallest rear sprocket)
+ (number of teeth on largest front chaining - number of teeth on smallest front chaining).

On my hybrid I have an 11 - 34 cassette on the back giving a difference of 23, and a 48-38-28 set of chainings on the front giving me a difference of 20. This means I need a rear dérailleur with a cage capable of dealing with a total capacity of 43.

Sheldon's page about dérailleur selection is here: http://www.sheldonbrown.com/derailleur.html

There is also a capacity measurement given with dérailleurs which equates to the largest sprocket size it can cope with in terms of the number of teeth.


Rim width / tire section tolerance? I have a Mavic Open Pro rim in 700 diameter.

The manufacturer recommends tire widths between 19 and 28 mm : http://www.mavic.com/en/product/rims/road-triathlon/rims/Open-Pro

How strict is this recommendation?
Could I fit a 30mm wide tire on that rim despite the fact that 30 > 28?

Sheldon has a chart that shows what width of tire fits on what rim based on the width of the rim. He also notes that people often exceed the recommended widths with no adverse effects. He also notes the possible problems with straying too far outside the recommended widths.

It's also worth noting that tire width measurements aren't well standardized. Much like shoe and clothing sizes, some manufacturers' sizes may run a bit large or a bit small. They're really more like guesstimates.

This is due to a couple of factors. Manufacturers are under market pressure to produce the lightest components possible. If they can shave off a few grams by calling a 24mm tire 23mm, they just might do that. There's also the fact that the rim width effects the overall inflated width of the tire. If one manufacturer is building a tire with the intent that it's mounted on 17mm rim and another builds the exact same tire but bases it on a 21mm rim, the resulting measurement will be different.

Two millimeters over the recommended maximum is probably still going to be just fine.


Why does shifting under power affect shift quality? I recently was attempting to shift up a hill and observed that

The shifting levers on the handlebars displayed significant resistance to my pushing them.
Despite several rotations of the crank, the bicycle had not shifted gears.

Googling around, I've seen people claim that pedaling under power increases chain tension and that this chain tension will affect how easily the chain moves between gears.

Intuitively, this does not make sense to me, as how easily the chain moves orthogonal to the direction of travel (i.e., the ease of shifting) would seem to be independent of the chain tensions parallel to the direction of travel. This seems to imply there's a causal relationship between the relative magnitudes of these forces.

Moreover, given that the chain itself is the same length regardless of the power transmitted, it's unclear to me how pedaling increases chain tension. Is it that one part of the chain becomes more tense, and the other becomes less tense? A free-body diagram type explanation would be very helpful.

How might one understand or model the shifting action and mechanism in a way that explains why chain tension affects shifting?

There may be other factors that affect "shift quality", if I understand what you meant correctly, but the most significant by far is “direction of force applied.

Basically for a gear to change the mechanism just pushes the chain “off rail” enough in the direction of the new gear. When the chain has a higher tension applied on it the derailleur doesn’t have enough strength to push the chain “off the rail”. (Derailleur is the name of the part the pushes the chain)
If you still haven’t understood, imagine a line stretched between two fixed poles, if it is loose and you push it to the side it will move some, if it has a higher tension and you push to the side with the same strength and direction than before it will move less. And the tighter the line the less to the side it would move. A gear system has a minimum distance that it needs to move to the side so it can change gears.

More advanced, modern and obviously expensive have over time placed gears closer to each other and shaped individuals to make the “derailing” need a smaller push in a new direction, requiring less strength to push the chain and as a whole make the process more smooth.

If you didn’t understand something just ask.


Why is a steady cadence so important? Or is it? I read somewhere that steady cadence is a good thing but why is that?  It is analogous to running long distance where it is a good idea to set a reasonable pace and stick to it?  I would think that varying your cadence would give your muscles a chance to rest some.  I question whether the original claim is actually true.  I would think it would be more efficient to accelerate briskly then coast down, then repeat.

This "sawtooth" cadence question is interesting because with a car or motorcycle, you actually get better gas mileage if you accelerate briskly and then just coast down. For example, you are at a red light in pole position (first). The light then turns green. You then accelerate quickly up to the speed limit (say 50 MPH) and then let the car/motorcycle coast down to maybe 20 MPH and then repeat. This is actually more efficient (you will use less gasoline) than if you accelerated slowly and maintained the 50 mph. This has already been confirmed by many people that have tested it. It is also easy to confirm yourself, especially if you have a real time mileage display. It will be at maybe 10 MPG for a brief time while you accelerate then vary between 99 and and some lower number as you coast down.

Ok now to bikes. It seems to make sense that for a bike a similar thing should happen. Imagine a person pedaling an average bicycle 10 MPH on level ground with no wind. The amount of energy expended by the rider depends on several factors including what gear they are in. Imagine they are in the proper gear vs. much too tall (high) a gear vs. much too short (low) a gear. Problem is in the low gear energy is being wasting pedaling faster than is needed (for example 150 cadence). This is a "subpoint" I am trying to make related to the main point of "sawtooth" cadence I am working up to.

If I pedal 10 miles at 10 MPH at near constant cadence, that will be 1 hour straight on pedaling. How can my muscles ever get a rest? Compare that to pedaling up to 20 MPH quickly (briskly) and then coasting down to 3 MPH and then repeating. Here I use my muscles for a quick burst then spend most of my time coasting. Here my muscles get a good rest and the number of actual crank rotations is far less. 10 miles on my bike in my favorite middle gear (34/20=1.7) with my 26" diameter tires would require about 4500 crank turns. I suspect using the sawtooth cadence method would require far less, possible only 1/3rd or about 1500. It would be an interesting test to have someone make the trip using both techniques and report their level on fatigue afterwards.

Someone mentioned about pedaling then coasting a lot will make me look like a kid on a BMX bike. Well kids are generally lazy. Maybe they figured out it is easier to pedal and coast so that is why they do it.

Another analogy is at my workplace. Can I get more work done if I work hard but take several breaks or if I just work straight thru without breaks but I get more tired that way? For me, I need the breaks to stay productive.

Maybe for younger riders a steady cadence is better but I am wondering for the 50+ crowd if sawtooth is actually better.  I suspect it is.

This is really a pretty complex question. Without knowing where you read about "steady cadence being a good thing" or what the author meant it is hard to evaluate this statement, but this SE.bicycles answer presents data showing that riders don't ride at a steady cadence. Rather, they alter their cadence according to conditions of the ride, the level of power they wish to put out, and the choice of gearing they have available. So your initial premise may not be correct.

That said, assuming you are on a constant gradient, with consistent wind, trying to go as fast as possible over a fixed distance, then you want power to be constant, because constant power application is the fastest way from point A to B in those conditions. If power is constant, then cadence will also be constant, unless you are shifting. Most humans can maintain the same power over a fairly wide variety of cadence, even if it doesn't feel as good. Usually it is fine to self select what cadence you want. It may be the case that you prefer a different cadence when climbing vs on the flats. If that is so, do not feel that you have to shift to keep cadence the same as the terrain changes.

The second part of your question presents a scenario of alternate pedaling and coasting, and posits that since it may be more economical for automobiles to do so perhaps it will be so for human powered cycling as well. However, humans are not like internal combustion engines -- we have two different metabolic pathways to generate power, which are colloquially called "aerobic" and "anaerobic." Aerobic metabolic production of ATP via the Krebs cycle is relatively efficient, but when we need to produce power that exceeds our aerobic capacity we switch to "anaerobic" production that is sustainable for far shorter periods of time. Compounding this "supply of power" issue is the "demand for power". The demand equations for cycling power are well understood if not well known, but the aerodynamic component of drag varies with the square of airspeed so the power demanded varies roughly with the cube of speed in calm conditions. These two physical constraints mean both that cycling faster and then coasting requires more energy than cycling steadily at the average pace, and also that speeding up is more physiologically taxing. That is, 1 minute of high power followed by 1 minute of recovery is still more taxing than 2 minutes at the average power, even though the total joules of work performed is the same. This is the basis for why "high-intensity" interval workouts lasting X minutes can have a greater training effect but be much less enjoyable than the same X minutes steadily spent at the average power.

As it happens, here is a plot based on data from a segment of a ride where the rider alternately pedaled and then coasted. This segment of the ride was done on a flat road, with almost no wind. The upper panel shows cadence; the middle panel shows speed; and the bottom panel shows power.

The "sawtooth" in cadence and power are apparent, and you can see speed increase and then slowly decrease. For this roughly 4 km long segment using this particular pattern of pedaling and coasting, power averaged 100 watts. If, on the other hand, the rider had covered this same flat 4 km long segment at constant speed so that the distance and total elapsed time were the same, the power would only have needed to have been 70 watts, a savings of 30%.

In this case, the bicycle used was a geared bike, so had the rider changed gearing he could have produced the required 70 watts with many different combinations of cadence and pedal force. In other words, steady cadence need not have been used. This is an illustration that cadence isn't terribly consequential, and you have wide latitude to ride at whatever cadence you want to meet the purposes you wish to achieve. If you enjoy pedaling and coasting, there nothing wrong with that.


Disc brakes squeak on Trek mountain bike I have a Trek 3900 mountain bike with disc brakes, and I just took it out of winter storage to start riding it for the season.
Everything works well, except for one very annoying problem: when I stop the disc brakes make an extremely loud obnoxious squealing sound. Any ideas of what is causing this?
Thanks

The easy thing to check is whether the pads have got a little damp while you weren't riding it. The solution there is to ride it a bit. If the noise bothers you try riding with the brake slightly on to heat it up.

Unfortunately that conflicts with the other problem: if there's oil on the rotor you should clean it immediately and avoid using the brake until you can clean it (to avoid getting oil in the pads because they're hard to clean). Wipe the rotor with either disk cleaner or rubbing alcohol and a clean cloth. Keep doing that with new solvent and new cloth until no further dirt comes off the rotor. Then take a quick test ride, using the brake. Ideally pedal hard with the brake on, so you heat the pads and rotor (and also get an idea of whether the brake works). Remember that riding with the brakes on heats up the rotors - be careful touching them immediately afterwards. Wipe the rotor with a clean cloth to remove any pad goop.

If there was no squeal last summer the alignment should be fine. The way to check is to look at the gaps between the pas an rotors. Check from a couple of different angles, the pad should be parallel to the rotor from all angles. If it's not try squeezing the lever - some pads pull slightly off angle when they come off the disk.

If all else fails buy new pads, clean the rotors then install the new pads. Remember that the new pads will need a little running in.


Shimano bolts; oversized hex driver holes? Planning for failure? This is frustrating me. I recently bought Shimano Dura Ace ST-R9120 hydraulic levers/BR-R9170 calipers combination. Got to the stage of bleeding the brakes and removing the bleed caps from the tops of the levers. The caps, as tensioned from the factory, will not undo with a new hex key fully inserted in them. Instead the key takes some tension and then spins around in the hole without moving the caps. To remove the caps I had to get a large set of vice grip pliers and start the caps turning. Of course in soft aluminium that means the outside of the caps are now marked. A pair of these is now on the shopping list:

You might imaging this is using a ball-end key or the wrong size key. No, this is using a new metric set, fresh and unrounded. Nor is it undersized, same as every other key or socket I can find.

Same situation with various other Shimano bolts. Though larger bolts will not let the wrench spin in the socket and fail to move they will grab the wrench when tightened to torque as if the bolt head is deforming and requires some backward movement to release the wrench. Not using too much torque - in fact using a torque wrench to specification.

What is up with their bolts? Am I supposed to buy Shimano 2.55mm hex keys or something here? Are they just using hex driver sizes inappropriate to the bolts? Maybe hex is just bad at transmitting torque and we should be using square (Robertson) drivers.

Well, it's no just you, my ST-R9120 bleed srew accepts 2mm (as stated in manual) very loosely too, 2.5mm is too thick, there's even a whole thread on WW dedicated to the issue, apparently those screws are/were of very poor quality, this was not the case with ST-RS685. Some of proposed "solutions" are:

Hammer T10 in. Now you have a T10 screw, but this still might not help or even damage the threads.
Or file a flat screwdriver slot and use it instead.
Contact Shimano for a warranty.
Buy replacement screw(s) (Y0C698030).
Try to push hex key further, some people stripped the slot by not pushing the key deep enough.
File a 2.5mm hex key down so it fits tightly.

Update: among three sets of hex wrenches I have access to, one had 2.5mm  tight enough not to strip the bolt. Both bolts unscrewed with a slight click. So, #6 worked for me.


Would a military helmet make a safe alternative to a bicycle helmet? I am in need of a new bicycle helmet and have been exploring some alternative options. One possibility I am considering is visiting my local Army Surplus store and getting a helmet there. I only use my bike for commuting, 3-4 miles in a single trip, tops. So the weight or lack of ventilation won't be a problem for me. Additionally, having a helmet durable enough to not need replacing after a minor bump or contact with the ground seems appealing (and cost-effective).
Right now, I am thinking something along the lines of a vintage WWII helmet.

So my question is would this be a viable and safe option for me or do I need some sense slapped in to me? I figure if it's meant to deflect bullets or shrapnel, then it should work fine for a fall or if I get hit by a car.

Obviously, I'll have look into the legality of this for my state on my own. But I am wondering if anyone out there has any experience or advice for me on this topic.

Thanks.

Bicycle helmets contain crushable foam that works to extend the duration of impact by about 6 ms (milliseconds).   This doesn't make the impact force disappear, instead it extends the duration of force experienced by the brain.  By extending the duration, you reduce the peak force.  The brain can withstand impacts to some degree, however if the impact is too forceful over too short a period of time (like your head hitting asphalt), the peak force experienced by your brain becomes too high resulting in brain damage or even death.  While 6 ms may seem  small, it can be enough to reduce the peak force experience from lethal and/or damaging to survivable and/or reduced damage (see Figure 1).

A)  B)
Figure 1.  Impact force by time a brain sees with a helmet (A) and without a helmet (B).  The total energy is the same (area under the curve), but the peak force is lower for the brain with a helmet.  (Source: http://www.bhsi.org/)

Modern military helmet are designed to protect against things like shrapnel, not absorb impacts (although newer research may change that).  As a result your peak impact force in a crash will not substantially change and you will be under a similar risk for brain injury as being helmet less.

Also you mentioned having to replace bike helmets that take an impact as a downside. If you wonder why bicycle helmets are not made with foam that "bounces back" (e.g. hockey helmets) this is because it can cause more damage in an impact.  With this type of foam your brain receives force in the initial hit and then it experiences a secondary "hit" as the foam returns (often these non-crushable foams return rapidly).  Crushable foam however does not rebound as it remains crushed. The downside is that once it is crushed it no longer provides any protective benefit and needs to be replaced. By extension when the crushable foam degrades it also needs to be replaced.  This is why it is also suggested that old bicycle helmets also need to be replaced (what constitutes old is up for debate).  In this case the crushable foam has degraded over time and its impact absorption properties change for the worse and will not provide the same benefit in an impact as a newer helmet with foam that has not degraded.

Finally, I do remember hearing about a new type of foam that behaves similar to the crushable foam used in helmets, but rebounds slowly.  I will have to work to find that reference. But if they are in the marketplace they will be more robust to hits and repeat impacts.


Reverse Gear in Bicycles For an ordinary bicycle (neither fixed gear nor capable of changing any gears).

Is it possible to modify it to have a reverse gear on it?

(i.e. reverse pedaling causes the bicycle to go backward)

(By modifying or attaching components to the rear wheel)

Thank you in advance

Such a hub exists for trike and quads . Pedal forward with 3 or 5 gears then having a coaster brake to stop . At full stop with the brake engaged continued backward pedal pressure will cause the cycle will move in reverse in a reduced gear . Sturmey-Archer has made these hubs for the niche market (velomobiles ) for some years now . The hubs have a sprocket bolted to the right spoke flange to drive the rear axle , some clever types have removed this and laced it into a wheel for a single rear wheel trike . Maybe this could work for a bike , still a question of balance in reverse ?!

  model QS-RC5 with reverse+coaster brake
  model TS-RC5 only coaster brake and no reverse

SA Specification Sheet PDF

5 Speed internal gear hub with coaster brake
Special use hub, includes a reverse gear on QS-RC5 model

There's also a 3 speed version with reverse, model QS-RC3.

Specs

Hub Shell Material - 6061 Aluminium
Axle Diameter - 13/32” Slotted
Axle Length - 185mm
Over Locknut Dimension - 139mm
Right Axle Protrusion Length - 24mm
Left Axle Protrusion Length - 22mm
Flange Width - 65mm
Flange Sprocket Teeth - 22T
Flange Sprocket C.L. - 39.4mm
Sprocket Teeth - 21T through 22T
Sprocket Chain Line: 53.9mm
Indicator Chain - HSA585 Mark Yellow
Weight - 2010g

Gear Ratio

  • Overall Range - 256%
  • Gear 1 - 62.5% (-)37.5%
  • Gear 2 - 75% (-)25% (Gear 1 + 20%)
  • Gear 3 - 100% Direct Drive (Gear 2 + 33%)
  • Gear 4 - 133.3% (+)33.3% (Gear 3 + 33%)
  • Gear 5 - 160% (+)60% (Gear 4 + 20%)

Chain sprockets mounting: 3 notch mounting
Colour:   silver
Flange distance (right):  39 mm
Flange PCD (right):   67 mm
Flange distance (left):   32 mm
Flange PCD (left):    67 mm
Over Locknut Distance (O.L.D.):   139 [EN] mm

There's an operation manual available at https://hfchristiansen.zendesk.com/hc/da/article_attachments/115010677845/Manual_-_QS-RC5.pdf

To operate reverse, you stop the bike, then start pedalling backwards.