How to effectively hitch a bicycle with a scooter? Background: I was getting back home from school one day but noticed the front tire of my cycle was deflated. The nearby shops were closed that day, and I had to walk nearly than two kilometers to get to the nearest cycle pump. The last time this happened, I manually walked that distance. But this time, one of my friends - having a scooter - offered me help.

Situation: My friend rode his scooter slowly, while I sat on the backseat of the scooter. The scooter is like this:

I held onto my cycle through the middle of its handle ("middle" = that part from where a rod extends downwards into the front tire). My left hand gripped the cycle handle at about my waist level height when sitting.

Problem: within thirty seconds of his starting to ride, my balance completely corrupted. He didn't stop the scooter and my cycle's front tire started spiraling. Ultimately, my left foot got entangled in the front spokes of the tire. The front tire did a 180 deg spin, the cycle fell (and I twisted my leg, but somehow saved myself from falling over my bicycle). I obviously want to avoid this from happening again.

My question: What is the most effective method to hitch my bicycle in this situation?

No, no, no. Just no.

Two kilometers is only a half-hour walk. That's hardly a big deal. Why risk injuring or even killing yourself to save what can't be more than 15 minutes by the time you've called your friend and they've come to get you.

Alternatively, fixing a puncture "in the wild" just needs a spare inner tube, tyre levers and a pump. That takes up very little space – you can get very small pumps, such as this one (random product link; not an endorsement). If you have a locker at school, you could leave the things there, rather than carrying them back and forth. This is what I carry around with me in case I puncture, with a ruler for scale. Total weight is 205g and that's with an aluminium pump instead of a weight-weenie carbon one. If your wheels aren't quick-release, you'll need a spanner/wrench, too.

Alternatively, take the wheel off your bike and use your friend's scooter to carry just the wheel to a place where you can repair it.


What's the best technique for removing a tyre from the rim? This question talks about fitting a tyre back onto a rim, but I'd like to know how to get the tyre off in the first place. Especially if the tyre is very tight, or the dip in the middle of the rim section is very shallow.

Most of my bikes have 406 wheels, and I use Marathon Plus tyres which are quite rigid, so they're really hard to remove without breaking tyre levers or pinching the tube.

What's the best way to get those tyres off the rim so I can fix a puncture?

(I've just realised we don't actually have this question, or any answers!)

First off, you usually only need to remove one side of the tire if you're just fixing a puncture.

If the tire isn't fully deflated, let all the rest of the air out. It'll make your life easier.
Using your hands, grip the tire near the valve and wiggle it a bit to loosen the bead up from the rim. Work your way around the tire, repeating this process until you get back to the valve. If you've done this and step 1 properly, the tire should be loosely flopping around inside of the rim.
Grab three tire levers. You can do the job with less, but it's harder. I've never needed four. The ones that will get tire off most easily will have a hook one one end, like these:

Insert one tire lever underneath the bead just above the spoke that is most directly opposite of the valve. The tire will be a little looser (more loose?) directly across from the valve and thus, easier to remove. Pry it up and hook the other end of the lever on a spoke.
Check to make sure that you've only got one side of the bead under the lever. If you've got both sides of the bead, the rest will be somewhere between very difficult and impossible.
Repeat step four on the spoke to the right of the one you just hooked, and then the spoke on the left.
At this point, the tire bead may be loose enough that some of the tire levers fall off. If so, great. Pry it the rest of the way off with your finger. If none of the levers has fallen out, it's ok. You just have a tire that fits a bit more tightly. You should still be able to get your finger in just to the outside of your three spokes and slide it along to pry the tire off. As I mentioned before, I have never had to use a fourth lever.
By now, you should have the bead completely removed on one side. You can remove the tube by reaching into the tire opposite of the valve and just pulling it out. You'll reach a point where the valve is the only thing holding it in place. Push the tire out of the way and remove the valve.
If you''d like to completely remove the tire, you'll be able to just yank it off the rest of the way with a firm grip.

The steps above will work on any tire. Skinny, hard case, non-foldable tires tend to be the hardest to get off. Fatties that are foldable can often be removed with nothing more than a good yank. If you have the option, it's still better to do it with tire levers though so you don't risk pulling too hard and damaging the tube. Tires inbetween those ranges tend to vary in difficulty.


Eye protection for child in bicycle child carrier I'm finally at the stage where I'm about to install a front mounted WeeRide child carrier on one of my bikes, but one of the things I'm concerned about is eye protection for my child. I'm mainly concerned about UV protection in addition to dirt/stones hitting that area of his face. I won't be going off road at all so no bushes etc to be worried about and all journeys will be around the suburbs.

How have other people approached this? Have you opted for child glasses (sunglasses or clear lens?) or goggles or something completely different?

What is the eye protection protecting against?

Stones up off your back wheel - then install a full mudguard/fender.
UV light?  Then kid sunglasses should do the trick
Bees bugs and insects?  Again sunglasses
Nasty sights on the roadway?  Really dark sunglassess.
Aero advantage?   a fully aero helmet and skinsuit will be required.
Or try nothing and see how it goes - kids don't need to be cotton-wooled all the time, just gotta pick the times.

Note, that second-last one is humour.


What are the most common causes for hysteresis in the rear derailler? I have often seen derailleurs on cheap MTBs to degrade in performance by showing hysteresis. By that I mean that to switch to a certain cog, one needs to shift one cog further and then immediately one back to get the chain to the desired cog.

What could be the cause for such degradation of shifting quality. Is this often a tuning problem, or wear, or the derailleur spring getting stuck with dirt and grime?

Here is the list of things I usually check for when troubleshooting jumping gears:

Is the chain always goes up/down? In this case usually the adjustment is off. Try adjust the cable.
Is the mech hanger bent? Sometimes during a crash you can bend a mech hanger. Most of the times you can bend it back, but there are cases where you need to replace the mech hanger for a new one. Usually they are cheap £5-15.
Is the shifting very slow? Dirty outer cables and rusty inner can cause the problem with shifting. Replace inner cable and outer cable for new ones.
Is the shifter clicking OK? I've seen cheap shifter wearing out and not "holding" clicks properly, so the chain would jump.
Are the mech cogs (small chainrings) worn out? are they wobbly? Chain can only be placed properly if the cog is not moving sideways. If that is the case, replace the top cog. Also worn out cog can affect the shifting performance.
Is the mech itself not bent or otherwise damaged? There are plenty of ways to destroy the mech.. usually that is beyond repair and you need to get a new one.
If the mech is very-very cheap, it sometimes gets bent while in normal use (not MTB abuse). Only replacement will fix that.

Good luck! And I'm off to fix my wife's bike gears -)


Rear wheel not straight because of worn out dropout? I noticed that my rear wheel wasn't straight and even after realignment it wouldn't stay straight. After some investigation I noticed that my rear dropout appears to be worn out:

Is this the problem? What is the cause? Is this normal for a bike that is a little less than 2 years old? Is there any repair option aside from changing the frame?

The quick release was bent and replaced some months ago.

This almost exclusively happens because of external cam quick release skewers not clamping the wheel tight enough.

Bike manufacturers love them because they're light, cheap, work fine most of the time, and nobody ever questions them when buying a bike. But they never have as much clamping force as internal cam types, and the problem is exacerbated once they're weathered and worn. There are some out there these days coming on some bikes that barely work or don't work. I know it sounds conspiratorial, but it's sadly true. There's a certain bike model I've been dealing with where the skewers just go in the trash, because the resting spot of the cam produces so little clamping force that using the front brake at any speed readily shifts the axle around.

Another possible issue in the same vein is wingnutting down the skewer instead of properly clamping it.

You could try some metal filler on the frame plus a good skewer, like any Shimano. Glob the filler on more than needed and then use files once it hardens to take off the excess and recreate the axle groove. The upshot here is that nice skewers put on so much clamping force that the frame isn't going to receive the kind of stress that caused this. This is a little bit of an experimental solution so I wouldn't expect a shop to do it.


How to clean tubeless tire sealant from rims How to clean the stuck/dry sealant from the rim edge, and the rim tape, etc? (In order to replace my old tubeless tyres with new, and the new ones to sit on a clean/fresh surface). With water? Water/soap? Any other liquid?

I did this weekend it was not hard to do it mechanically with a piece of cloth and water. Then for patching I needed a piece of a very clean surface so I used a dish-washing liquid and then finally isopropanol buth that will probably not be necessary if you do not need patching.

From the rims the mechanical way was enough, a dry piece of cloth or even just fingers were fine, but a wet cloth will be easier.


Data on cable lubricant Chain lubrication is a popular topic. Perhaps for this reason, it is possible to find data for chain friction and chain lubrication. Some of the results of the research are quite interesting. I'm speaking of results such as these:
https://www.ceramicspeed.com/media/3505/velonews-friction-facts-chain-lube-tests-combined.pdf
I have a cargo bike which uses cables for steering. This application is really demanding on the cables, probably more than braking which puts the cables through less motion than steering does. So I really want to lubricate the cables with the best lube. Is there any research like this, with real empirical data, which compares different cable lubricants instead?

A couple of thoughts:

Manufacturers would have the best information about this.  If they are using another company's product, such as when Trek installs Shimano brakes, they generally follow the original producer's guidance; in my example, Trek will generally follow Shimano's advice.  When they vary from it, it's because they have considerable engineering expertise of their own, as well as direct contact with their supplier, and can make very well-informed diversions from that advice to suit their particular situation.  The upshot?  Do what the manufacturer says.
What if the manufacturer doesn't say?  That's more complicated, I suppose.  Cables in general are susceptible to temperature- and friction-related degradation in performance.  A lubricant that avoids those pitfalls is advisable.  One option is powdered molybdenum disulfide (possibly blended with PTFE powder), applied minimally.  It is a powder, and so does not become more viscous with lower temperature.  It also does a great job of reducing friction.

In the end, though, if your ability to steer depends on cables, and you are noticing reduced performance from the cables, they should be replaced.  I recognize that this does not meet your request for data, but I hope it has some value nonetheless.


Are fatbikes capable riding in mud? Fatbikes are traditionally used for sand and snow which are surfaces which are loose and liable to break away under the weight of the bike and rider. They are also materials that don't generally stick to the tyre.

A muddy surface such as a peaty or poor-condition dirt track after rainstorms would also provide some likelihood that the material will break away under the tread. However, mud is often sticky and likely to stick to a tyre.

Therefore is mud more or less likely to stick to a fatbike wide with and diameter tyre than a small skinny ( < 2.5 inch ) mountain bike tyre where more pressure is being exerted over a small surface area, or more extreme a cyclocross tyre (these guys seem to ride and corner in muddy conditions successfully)?

Depends on how viscous and deep the mud is.

If the mud is viscous like clay and maybe leaves mixed and a fat tire can float and still get traction then the bigger tire is better.

But with normal mud and less than 6 inches deep then a thinner tire that will sink to the bottom for traction and might do better.

I was in a cyclocross race recently where we had a few inches of rain over the prior 2 days.  There were both mountain bikes with 2+" tires and cyclocross with 33-35mm.  The cyclocross were more effective.  Even muddy grass the smaller tires did better.  The bigger tires got pushed around and still did not get good surface traction.

The other factor is the amount of mud you are going to carry.  A fat tire is going to hold a lot more mud and get heavy.


Can heavy tires handle anything that the trail can offer? I got a Slash and it came with Bontager XR4 Ellite tires.

The same evening at the park I had a puncture. Turned out the offender was a thorn to the sidewall (I rode through some cut off and now dry bushes and tree stems).

I intend to ride the bike over snow, ice, mud, sharp rocks, large round rocks, road, but mostly trails, that can sometimes have sharp stones or thorny plants. And wound NOT want to patch both my tubes every time I go through some strawberries.

So I am considering moving to very heavy tires, e.g. Scwalbe's Big Betty or Wicked Will. Would this mitigate my concerns?

Alternatively, the current tires and rims are marketed as "Tubeless ready". Maybe it would be a better bet to move to tubeless setup? But then, why didn't they sell the bike in TL configuration, if that would be better?

I do not ride at competitions. My goals are to be able to ride to the top of the mountain without lagging behind my friends, and then enjoy the descent.

I certainly feel your pain about having to repair tires all the time. I've been stuck 10 miles from the trail head with a cut in a tire that caused me to constantly stop and add air as I limped back (second tube of the day).

Bigger, beefier tires will help, but if your plan is to make it up the hill with your friends and not be totally gassed then I wouldn't recommend full DH tires. I switched out my rear on my AM rig from a 2.35 to a 2.5 and boy does it chug when laying down the power. On the other hand, I can point it downhill and not even worry about it, and the grip is fantastic.

For good, all-around trail tires check out something in the 2.35-2.4 range that's made for All-Mountain/Enduro as these usually have thicker sidewalls and harder rubbers.

As for going tubeless, that will certainly help. The sealant will handle most of the punctures that you're likely to get, but I have heard of folks getting numerous punctures that have slowly bled the air from a tire. The problem with tubeless when riding more aggressively and on harder terrain is burping, where the tire briefly comes out of contact with the rim and you lose some air pressure. No amount of sealant can prevent that.

My bottom line recommendation is to go with a split tube/tubeless setup. You can hit everything from fast XC trail to full on DH and be covered in the case of punctures and big hits. Sure it's a little heavier, but you won't be running big huge tires either.


How to fit a Storage Options bike cam helmet mount I recently bought a helmet and handbar moutable camera made by a firm called storage options.  The instructions do not explain how to fit the strap for helmet attachment.  It consists of a ring of elastic with a further piece of elastic attached at right angles to the ring to form a half circle above the ring.  The camera mount is at the T where this extra piece attaches to the ring, and is oriented in the same direction as the extra piece.

Here is a photo of the strap.  I think that the camera is supposed to be inserted in an upwards direction into the area above the buckle on the lower strap (although this doesn't seem like a secure mount).

Here is a photo of the camera in situ on a helmet.  As you can see it's not entirely clear how the straps are arranged from this photo

Does anyone know how to fit this to my helmet (which has a sun visor and to the best of my knowledge is a Giro Venti)?

It's designed so the bit at the top of the picture wraps around the helmet like a headband while the part of the strap that is making a "U" in the picture goes across the top.

To keep it from coming off, you'll need it to be fairly tight. This is okay with the helmets that are similar to skateboarding/snowboarding helmets (hard shell), but can make some of the more pricey (lighter) bike helmets lose integrity.

If you aren't going hard down single track, this will probably be okay, but be ready for it to slip off if you are doing anything that rocks the boat much.


long distance touring: is high tensile steel silly? I am planning a touring trip, let's say around 10'000 km, across Asia more or less.

I have no intention at all to buy one of those several thousands - worth touring bikes.

Apparently, on a lot of websites, high-tensile is described as pure rubbish, without much more arguments (heavier..big deal...what else?). I have troubles finding a ChroMoLy steel frame, so here is my question:

Is it THAT silly to plan a trip with a high-tensile frame? (Brand:Giant Model:Chicago year: no idea, I guess mid 90's, not a single scratch on the frame, I am pretty sure the bike has been stored in a garage)

Any story to share on the topic?

thank you!

Any steel, even hi-ten is less silly than alu for the trip you're planning and the age of your bike. The endurance strength of steel is much higher, and the material itself is not as bad as it's said to be. Also steel is easily and cheaply repairable, which is a serious advantage when you're going on a long tour with potentially few bike shops. But the problem with hi-ten frames is that these frames mostly exist in rreally cheap bikes, where the quality of manufacturing and quality control are quite poor. With a frame this old it means it could crack any time.

Comparing your frame to a new one, it would be much safer to buy a new one. Simply because it's new and the material and joints aren't fatigued (and the fatigue would be much quicker with you and racks full of luggage). But comparing a new cr-mo to a new hi-ten frame, there's not too much of a difference in terms of what they offer for touring bikes. Hi-ten steel has lower tensile strength, but higher ductility, so it's more prone to damage at extreme loads, but will bend rather than crack.
Well in the end it's all a matter of compromise and in case of this specific tour, it would be largely opinion-based, thus out of scope of this site.


Replacing my bottom bracket. I need help IDing a replacement So I have owned a Swhinn Network 3.0 (21-speed. Square tapered BB. All aluminum) for almost 5 months, and at about month 3 the bottom bracket started giving me some noise. I work in a bike shop on my UNI's campus so I opened it, purged, and re-lubed it. All was well. The it made noise again in two weeks. Rinse and repeat. Then again a few days ago it stopped turning. I got it to move again, but learned the bearing case (the little metal ring with the hooks that holds the little balls) had been flattened, pressed, warped, and demolished, so I removed both of them and put two more bearings in each side (22 bearings total) to occupy the excessively empty space and it worked fine for another two days until it started clicking again.

I am giving up on it and want to buy a non-servicing BB, but with all the acronyms and numbers and measurements I am not completely sure I can accurately pick the right one and not waste my (limited) money. Sheldon Brown is extremely confusing, and I can't make heads or tails of what he is saying, and can't seem to find my current BB on there anyway. What I have found that seem like they'll work and why/why not are listed below:

Shimano BB-UN26 - My bikes BB case (Terminology?) is 68mm, and the spindle is 125mm. It seems like the 68x123 might work, and thats only bringing each crank 1mm closer. Or I cuold play it safer with the 68x127.5 and tolerate the extra 1.25mm on each side (easy peasy, right?). My issue with it is the plastic cup. Is that a bad idea? Also, whould chainline matter at all if I get a BB with equal spindle length?

Shimano BB-UN55 (can't link, but it is on amazon) - Basically the same as UN26, but with an alloy cup instead of plastic. My frame is aluminum, so would this be bad to get, or good?

Are there any BBs you prefer that you'd recommend, or can I just run with one of these? I only have a week before I lose access to my tools, so time is also a factor, and if I can get it on Amazon Prime that would be most preferable.

You have done your homework correctly. You need a square drive bottom bracket with a shaft length as close to 125mm as you can get to fit a 68mm frame. I have taken out quite a few of the plastic cup units with no issues, but I prefer the metal one. But that is just personal choice. Take a look at the area of the chain stay (the tube from the rear axle to the bottom bracket) for crank clearance. Some frames run the big ring very close and bringing the crank closer may cause an issue. You can use a shim behind the crank- side cup to move it out to the same location as original. It is doubtful you will notice the difference if the nondrive side is a mm closer to the centerline. you will likely have to fine adjust the front derailleur when your done.


Tighten vision metron aero brake lever I don't see the screw to tighten on the Vision Metron Aero Brake Lever
How do I access tightening bolt?

perhaps this video might help. I'm not sure if you have the same brake levers.  The part where he installs the brake levers is about 6 minutes in, which the link should go right to.

There's a small hex key bolt on the outside of the brake levers. You should be able to see it in the following picture, I have circled what I'm pretty sure are the screws you are looking for.

The installation instructions linked to from the page you linked to shows the "fixing bolt" labeled as "3" in the following diagram


Will any Shimano mountain bike shift cable set work with any Shimano mountain bike derailleurs and shifters? (Forgive me if this question has been asked before - but I don't know if I'm searching with the correct keywords to find the answer...)

My rear derailleur cable is stuck hard into the side of its tube, meaning I can't shift gears. I want to replace it, but I'm a novice and I'm not sure exactly what replacement cable I need. The bike is a Cube Analog 2014, with Shimano Altus SL-M370 Rapidfire Plus shifters and Shimano Deore RD-M592 SGS Shadow 9-speed rear derailleur. I found this Shimano shift cable set, but it seems like this is a generic kit. Would this work? Would I need to cut it to the right size for my bike, or are they always the same size?

Yes it will. The important factor for compatibility is the head of the cable that sits inside which will be the same. The cables will be significantly longer than you will need, so you'll have to cut them down to size. Use the old cable housing to determine the length of housing that you need (provided that it's been working well at the current length). Then thread the inner cable through to the derailleur and adjust your cable tension, then cut off the excess cable.


Leaking Slime inner tube valve after opened for first time since install I put some extra air in my rear mountain bike tyre yesterday. It uses the SLIME inner tube. It wasn't flat nor had a puncture, I was just topping it up to make the tyre a bit harder.

I cycled to work on it and all was fine. When I came out of work however, the rear tyre was completely flat. It was absolutely fine when I got to work though.

It appears that since opening the valve to pump in some air, it's been slowly leaking back out of this valve. It wasn't a problem until I did this. It's a schrader valve if of any use/relevance.

Is there anything I can do? I pump the tyre up and it just deflates again through the SLIME inner tube valve (which has spat out a bit of it's green gunk incidentally). Just seems like a complete waste of money at £16 per inner tube if it just leaks via the valve (regardless of whether it's going to seal any punctures or not).

You might want to remove your Schrader valve's stem (innards) with a stem removal tool and check the valve's rubber seat, located on the part that you remove. There may be debris lodged in the valve seat such as grit or sand or some dried slime that would cause it not to seat and seal properly. Also consider switching the valve stem core from another valve from say an old inner tube and see if that does the trick. Unless the valve was damaged or the old tube you take it from is real old, the valve stem core will usually last much longer than the actual tube. Many years ago when my bike had Schraders, I'd keep a couple of valve cores from old tubes in my patch kit in case I experienced a valve problem when out on a trek.


Lights wiring polarity and wire marking I am re-wiring my bike lights to add a smartphone charger and improve the connections. Wires are going in pairs, one wire in a pair being marked with a white stripe. Since I am using LED lights, polarity is important. On electronics SE and in many places on the Internet I found that the white-marked wire should go to the plus. However, my hub dynamo has the marked wire connected to the contact marked with the ground symbol (so it is connected to the frame). Usually in electronics the ground is negative. Is it a mistake of the bike manufacturer or am I missing something?

White stripe is ground. Consistency is a virtue, and Schmidt's obvious decision tells us the industry default. In principle, the two conductors are interchangeable, because AC. However, in the reality of bicycles, there are practical considerations. Some dynamos ground one side of the circuit through the axle and some don't. Some lights ground one side through the mounting screws and some don't. Some bike frames are conductive and some aren't (and headset bearings are intermittent). So it is important for all deliberate connections to have compatible ideas of what is ground. Otherwise you have a short circuit. When a mechanic replaces your dynamo or light with a unit that makes an assumption about what's grounded, the assumption better match your wiring.


Rear Derailleur - getting stuck in largest rear cog Bike is only about 4 months old. I was indexing my gears last night, and the rear mech cage is getting stuck when shifting from largest cog to second largest cog. If I shift to the third largest cog, it will pull it down. Shifting from second largest to largest works fine.

I've played around with the cable tension, etc.

I tried pushing it inwards without the cable attached and the same still happens but it eventually pulled its self back in.

Any ideas?

On my bike I need to be on one of the smaller front cogs for lower gears to work correctly. If I'm on the large sprocket lower gears are unreliable due to the bend in the chain. My owners manuel said not to use extreme combos eg large front to large rear


How to choose a frame to be sure it fits to the owned components? I have parts from another bicycle which got it's frame broken. What criteria should I check before ordering a new frame to avoid compatibility issues with old parts?

This is pretty broad, and it depends on how much stuff you want to move over. I'll assume the fork, frame  and headset itself are not being moved, so you're getting new ones of those.

Brakes: Mounting, reach for rim brakes (can the brake, when mounted, reach the rim properly?)
Wheels: Frame spacing and brakes (if you have to switch brake types you may need to switch wheels). Also, axle type (can't put a thru axle wheel in a regular frame, for example, though some hubs are convertible).
Stem: Threadless/threaded depending on the new frame. If you switch stem types or stems, make sure the new stem can clamp on the new bar.
Handlebar: See stem. Also, anything that mounts to the handlebar will need compatibility checks if you change diameters.
Front derailleur: Same type of mount (E-type, etc.). These are cheap though, so replacing them is no big deal.
Bottom bracket: Depends on the frame. You'll probably end up installing a new one though.
Crankset: Depends on the bottom bracket.
Seatpost: Depends on diameter.
Saddle: Probably will.
Rear derailleur: Probably will.

Note that you'll likely be using a shop to move some (all?) of the parts, and at least for prepping the new frame (e.g. chasing and facing the BB and what not).

So, you might as well go through them to get the parts and double check compatibility.


How could I have fixed a flat tire? My tire was flat and I could not fix it, so I had to carry the bike all the way. How could I have fixed it?

Well, it's a complicated question, because there are several different cases to consider:

The tire is simply flat because the air leaked out slowly.
There is a hole in the tire due to a nail or thorn or shard of glass.
There is a large hole or cut in the tire.

Slow leak
The first thing you need is a pump.  Sometimes (but not usually) you can pump up the flat tire and it will hold air for 30 minutes or so, allowing you to ride home or at least letting you ride for several minutes before you stop and pump it up again.
Hole
The normal case is that there is no obvious damage to the tire, but when you try to pump it up it doesn't hold air.  Then you need the pump, "tire irons", and either a patch kit or a spare inner tube.  You may also need wrenches to loosen your wheel, if it does not have a "quick release".
The procedure is to remove the wheel from the bike, then use the tire "irons" (most of which now are actually made of plastic) to pry one side of the tire off the rim.  (This procedure is a bit more complicated than that statement -- it takes practice to do without damaging the inner tube further, and an entire article could be written on this topic alone.)  Then remove the inner tube from inside the tire.
At this point, even if you have a spare tube, it's wise to attempt to find the hole in the old tube and then look at that spot inside the tire to see if there's still a nail or thorn sticking through.
Using spare tube
Then, if you have a spare tube, you install it in place of the bad one (pump a little air into it first to make it round), use the tire irons to get the tire back on the rim, and then pump up the tire.  I like to pump it up once, deflate it, and then pump again, to help position the tube and "seat" the tire on the rim.  Once it's pumped up examine the wheel for any obvious lumps (indicating the tube may be twisted inside) and to see that the tire is evenly installed on the rim.
Using patch kit
If you don't have a spare tube (but DO have a patch kit), you should attach your pump to the old one and try to pump it up.  Air will exit the leak, and you can hear/feel the air escaping.  Mark the hole somehow -- a pencil, a ballpoint pen, or a piece of chalk will work.  But note that you will be cleaning the area around the hole, so make marks well away from the hole that you can line up to locate the hole after cleaning.
Read the instructions that come with the patch kit.  Usually you clean around the hole using the sandpaper that comes in the patch kit, spread glue (also in the kit) around the hole and let it mostly dry, then attach the patch over the hole.  Then it's usually wise to wait 5-10 minutes before inflating (though during that period several times pressing the patch tightly against the tube).  It's probably a good idea to then inflate the tube a bit to be sure that there are no more holes and that you covered the one hole correctly.
I like to spread some chalk powder or simply a bit of dust from the ground over the patch area to keep it from sticking to the inside of the tire.
Reinstall the tube the same as with the spare tube.
Large hole
If you discover that you have a large hole or cut in the tire then it's necessary to use some sort of "boot" inside the tire, to keep the new/repaired tube from bulging through the hole.  Of course, some holes are simply too large for this to work, but usually it's worth a try regardless of how big the hole is.
For a boot you want a piece of thin but relatively stiff/strong material.  Special strips of reenforced rubber are sold at bike shops for this, or you can cut a section from the side of an old tire.  A popular technique in the US is to use a folded-up dollar bill -- the paper that the US dollar is made from is quite durable and stiff, and, if a relatively new bill is folded into four layers it works quite well for small or medium holes.
To use the boot you get the tube repaired and installed, and just before you put the tire back on the rim you work the boot in between the tube and tire so that it covers the hole.  Then put the tire back on the rim and inflate.


How long should it take to rebuild a wheel? I'm planning to replace the hub on my front wheel, from a QR to a 20mm.

How much labor, skill, equipment, etc. does that need, and how much time should I expect a pro to charge for, to do the rebuild?

I think if you are willing to spend a few hours, it's worth doing yourself.  Depending on the flange size of the new hub, though, you may need to buy new spokes.  You can determine the length of the spokes you will need using a spoke length calculator.

You will need a spoke wrench, a flat-head screwdriver, some vaseline, and the use of a truing stand.  Here's what you'll have to do:

Remove the tire, innertube, and rim tape from the wheel.
Using a spoke wrench, loosen and remove the nipples.
If you are using the same spokes, remove the spokes from the old hub.
Lace the wheel, making ABSOLUTELY CERTAIN that the valve will be in the right place.  Check out Sheldon Brown's step-by-step wheelbuilding page for the procedure of lacing a 3x (three-cross) wheel.  You will want to use a little bit of vaseline on the threads of each spoke so you can tighten the nipples more easily.
Go to a nearby bicycle cooperative (you can google bicycle co-op near nameofyourtown) to use a truing stand, and use the truing stand to adjust the wheel.  Make sure the wheel is dished properly and that you have proper tension on the spokes.

Because spokes stretch a little and settle in after you start riding, be prepared to true the wheel after the first couple rides.

If you are not interested in making your own wheel, I recommend just buying a new wheel with the hub you want.  It may be cheaper than getting your lbs to rebuild your wheel with your new hub.


What's the correct position to assemble eliptic (Biopace, Rotor, etc) chainrings? If you take a regular, "classic" road chainring (130bcd, five arms), you have five possible positions to assemple it in the crank arm. This can even be used to "rotate" between different positions over the chainring lifetime and get a more homogeneous teeth wear.

But with elliptical chainrings, there should be only ONE position, shouldn't it? I mean, it was designed to have the larger chainring radius in a given position, so the question is: which position was it designed to work best?

Aditional question: would it be possible/wise to "tune" the performance for a given riding style, possibly going "against" what the manufacturer designed? It looks like RotoR and Biopace have different theories about that...

IIRC, there are at least 3 conflicting theories:

The rings should be oriented to extract the maximum energy from the most powerful part of the stroke (from roughly 3-oclock to 6-oclock, viewed from the right).
The rings should be oriented to maintain a (relatively) constant forward force/velocity, despite the change in leg force through the rotation.
The rings should be oriented to maintain "smooth" leg motion.  (Whatever that means.)

(1) would have the largest diameter parallel to the cranks, (2) at right angles, (3) somewhere else.

Update:  I have 1 and 2 backwards -- see jae's answer on that point.


Is cyclocross tire (CX) taller than normal road bike's? According to the specialized website, the 54cm crux 2021 comes with 700x33c cx tires.
https://www.specialized.com/us/en/s-works-crux/p/171342?color=271648-171342&searchText=91420-0046
And, its bb drop is 69mm and its bb height is 283.5mm.

That means its tire height is 41.5mm?
My current 700x25c's tire heigh is 25mm and I also ride a 700x44c and its height is about 40mm.
So, did I make wrong calculation? or CX's tire is taller than normal road bikes?
The calculation is
( ( 283.5 + 69 ) * 2 - 622 ) / 2 = 41.5

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

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


New to cycling, questions about over doing it I just got my bike last week, it's a single speed. I bought it to go ride the forest preserve trails near me for exercise and I don't know how far I should be riding before I'm pushing myself too far too soon. I've rode the past 2 days, 6 mile per day. Is this a good amount? Should I go further?

It depends on a lot of things, like how fit you are to start with and how well the bike fits you. The same distance can be a very different amount of effort depending on the surface, incline etc. But as a general rule (and assuming you're in decent health) tired is fine, muscle aches are to be expected, but don't ignore pain especially in your joints. As with any new exercise, do build in some rest days, and expect to build up what you can do.


How to repeat the success of Salsa Marakesh when mixing MTB and road components? Salsa Marakesh https://salsacycles.com/bikes/marrakesh/2020_marrakesh_sora is based in part on road Sora components and MTB Alivio components.
Let's focus on the front -- in my bike I have Sora brifters, I added MTB crankset (Acera FC-MT300) and I have MTB Alivio front derailleur (FD-T4000). To make it works I had to add jTek pull ratio converter. And with it, it works great.
And here is the Salsa -- Sora brifters as well, MTB crankset, MTB Alivio front derailleur. And that's it. No converter.
So my question is how can I simplify my setup (by removing cable converter) and make it work like in Salsa? The only difference I can see Salsa uses Alivio crankset, not Acera, and Salsa uses 48/36/26 chainrings while I have 44/32/22. I doubt the size matters here, but could it be upgrading to Alivio crankset would allow me to drop cable converter?

I sell that bike at work. The road/mountain FD mismatch functions very badly. We've had to replace the front derailleurs with road models. The total throw of a road shifter isn't enough for it to shift well and not have rub anywhere. It's terrible.
It can be made to kinda sorta work if you accept rub in the lowest gear. But, that shouldn't be acceptable. And the adjustment is totally finicky, i.e. the exact opposite of what one would want on a bike one may have to fix in the middle of nowhere.
There is no alternate cable mounting or trick. It's just a mistake on their part.
The really unfortunate thing about their choice to spec it that way is Shimano's latter-day road triple FDs, which are designed for 50/39/30, have no trouble performing acceptably with 48t trekking-style triples as long as the middle to large minimum tooth difference is respected. I believe the 22t total difference on a 48/36/26 pushes past the printed max total difference to do this on every pertinent model, so maybe that's why they consider it off-limits, but I've never seen that be an issue in practice, and if it was an issue, all it would amount to is chain rub on the bottom of the cage in small/small.
For a 44, you really need a mountain FD. The profile of a cage intended for a 50 will leave you with an overly large gap at the tail even with the FD down as far as possible, which in turn will cause iffy performance because of the limited contact made with the chain during shifts, as well as some risk of derailment from the excess gap.
There is a milieu of questions one can ask about making STI work with a road FD on various not-as-intended cranks and chainring combinations. These can be difficult to answer because in a lot cases the answer is it can function to some greater or lesser extent, but with a hit in performance, and whether the result is acceptable is up to the user. If you wanted to lose the adapter but give up the minimum on your low gear, you could switch your rings to 24-36-48, along with a road triple FD, and it would probably work okay as long as the rings were good quality and ramped, but it would be noticeably chunkier to shift, and it's pretty common to need a chain catcher in that setup. You may be able to get 22-34-46, or -48, to work okay, but both can have their issues too. It's a grey area.


How to start riding a recumbent bike? I want to try riding a recumbent two-wheel bike to see if its easier.  So I borrowed one and I just cannot get it to work right.

When the owner demonstrates it looks so easy and really fast.  We are the same height so it should fit me okay.  The bike is not faulty beause he rides it okay.

When I sit on the seat with the bike still its okay but when I start pedaling I can't balence and have to put a foot down really quick.  I tried to put my hand down but it hurt my shoulder.   Once my foot was trapped by the wheel and I fell down hard.

I am a confident rider who cycles 30 mins a day to and from work on a Trek commuter bike.  We tried on the flat smooth carpark at work not a road.

How do I get moving and keep my balance right from start?  Why am I failing so hard?

I do not have a photo of the bike, but it looks mostly like this one  from http://www.dtrecumbents.com.au/DTRecumbents/Images/ProGoal1.jpg  but rim brakes, no rack, no bag on the stem, and no headrest.

I do not use clips or cleats on my road bikes.

When learning to ride my first two wheeled recumbent, and when teaching someone else to start riding on it, I first rode without trying to pedal.
Using it as a balance bike, learning to steer and balance before you add the unbalancing effect of getting your feet on the pedals.

Not all recumbent bikes do allow that, as some have such a sitting/laying position that you can not get your feet on the ground and still be properly in the seat. But if you can get it to work it will help your muscle memory to get the right information to remember later.

When you are ready to start pedaling or if you can not use your feet on the ground while properly in the seat, find a post/hedge/person to hold onto while you put both feet on the pedals and give a shove (or get a shove from the person) trying to keep the bike as upright as possible.
If you have pedals into which you clip your feet, in the early stages of riding do not use that option, you will want to put your foot on the ground a bit too often for that.

If you have a wide path, empty car park or other safe and wide area to practice you can get going quite a bit off the expected angle.

Going down an incline will make it easier. Going up an incline, even a very tiny bit, makes it harder to start riding, even people who can get away easily on the flat hate to stop at traffic lights as you need to go a bit up (over the road camber) while going slow. So help yourself while learning and find a slight angle down to get started.
Not down a hill just a small incline, almost flat will be the best.

Start at 'the easiest' gear but as soon as you make any speed, gear up, go to a harder gear when you make some speed, that will help you to get stable, but do not try to get to the higher gears just yet.
It depends on the gearing on the bike whether you need the easiest but it should be a low gear.
When you start riding you will want to steer a little, to adjust for the bit of unbalance you are bound to get. If you tend to fall over in one direction you should steer to that side. Using one leg to start riding will make it more predictable which way you need to steer. (Only steer by a little bit, you should not expect to go at 90 degrees to how you stand.)

Check out (if you can) whether you over or under react when you balance. I found that on my recumbent bikes I tend to overdo on the balancing, they react very fast on the slightest change in position.
It is not easy to think how to adjust how much you change your position, but when you know what you do wrong you will adjust.

When the bike is set up right and set up to your measurements, it should not take long to get started. The recumbent bike sellers in the Netherlands all take new riders on a day tour in which they can try out a few different recumbent bikes, they allow half an hour at the start of the day for the people to get through the first stage, and after swapping over bikes (they adjust them on the road for this) it will be a few minutes to get used to the new bikes. I have never been with one of these rides, I learned on my own.
But I did start with a recumbent trike, so when I bought my first 'bent bike I was already used to the sitting position.
My first recumbent trike does not react at all on change in balance.
Now I own a Flevo trike and a Flevo bike, which required a new learning process as they have a different steering method. (Both mostly steer by balance, and are very fast in reacting on any change in position.)

I wrote this answer not going into what you already do/did right, more as a general guide than as a 'just for the OP' answer.
You do a lot right already, I think me mentioning them is more for the general picture and it did help me to name all parts of riding a 'bent.


Nukeproof Pulse SRAM PG-1030, 11/26, 10-speed to 11/36t, 10-speed I'm a bit of an amateur but looking for advice at the moment.

My cassette is 11-26t which is pretty hard for me (not that fit).

I'm looking at changing to the 36t which I can see would be bigger, if so would I need a new derailleur system and gear lever etc.?

Thanks in advance.

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

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

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

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

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


Making a left hand turn as a commuter I am thinking about commuting to school on my bike and wanted some advice on it. I do live in a very bike friendly neighborhood, but the thought of turning left on a 40mph road (no stop lights nearby and people speed) does scare me a bit.

What are your recommendations for turning left?
Thank you in advance!

What you do strongly depends on the road layout:

There is a dedicate bike lane
Stay on the bike lane and, if it also goes to the left where you want to go, follow it. Avoid cutting corners just to shorten your way and signal in time your intention (also other fellow cyclists prefer to know where you are going in advance). If the lane doesn't turn left where you would, follow next point.

You drive in the normal traffic
The normal procedure to turn left (assuming you ride on the right) is to get to the center of the lane and then turn as soon as no vehicles are coming from the front. Therefore put your left hand out in advance and make clear you want to move left. Wait some time with the hand out, check that no vehicles are approaching at your left and slowly but steadily move to the left. Complete the turn as soon as possible.

Alternatively, cross at a pedestrian crossing (dismounting from your bike if necessary).

In all cases:

Be visible: wear high visibility gears. Bikes are small and easily slip past consciousness in traffic.
Be assertive with your movements and don't zig zag. You don't want the drivers to assume you are just erratic in your cycling.
Listen and read the traffic. Learn to understand the context around you: are the drivers calm? Do you see anybody who is distracted or plainly a jerk?
Don't wear headphones or fiddle with your smartphone while cycling
Be fit and avoid cycling if you are not in condition of doing it. You want to be sure you can react promptly on the road
last but not least Safety first


Minimum dimensions of bike storage shed I am interested in buying/building a storage shed that can hold three standard 19" mountain bikes. Ideally, the space would be as small as possible while still allowing one person to get the bike in and out. I am fine with having to take all the bikes out to get to the one I want, but I don't want to have to disassemble the bike (I don't even want to take the wheels off) to put it away. What dimension should the shed be and how big does the opening have to be?

Width: If you hang the bikes on the wall, either "head to toe" or at staggered heights so that you can interleave the handlebars, then the width requirement is only slightly greater than 2x your handlebar width. Call it 60".

Depth: If the wall opposite the hanging wall opens like a barn door, then you don't need to be able to fit your body in the shed, and it only needs to be as deep as the bikes are tall, so that's whatever your seat height is above the ground, plus some clearance. Maybe 36".

Height: Length of bikes, end to end, plus some margin. Maybe 60"? Unless you're hanging them at staggered heights, in which case it's probably more like 75". And you'll want a little bit of a pitch to the roof so it sheds rainwater, so a few inches higher at one side.

These are all inside dimensions. If you're using 2x4s for framing, add 7" in each direction, plus the thickness of whatever your cladding is (plywood, chipboard, clapboard, etc). And don't trust some rando on the Internet--measure this out carefully before you start cutting materials.

I don't know how tight a space you're trying to fit this shed into, but you might want to consider making it a little bigger than this. Plywood comes in 4'x8' sheets, and every cut you save makes the project simpler. Plus you can leave room for your N+1 bike.

Making a shed that they can roll straight into will be easier to use day-to-day, but the width will need to be the total width of all the bikes at their widest point, plus some margin, so that handlebars don't interfere with each other.


What is the source of BB area creaking associated with ambient temperature changes? A general answer would be welcome, maybe encompassing -10C-40C/15-100F temperatures, but my particular ride is an aluminium frame with pressfit BB30 and Tiagra commponents, in Scotland's climate, stored outside but in a shed.
Last year I had a tiny bit of creaking/snapping from the bottom bracket/cranks, or at least it was at the same part of the pedal stroke each time. Through the winter when the temperature was generally 5-10C/40-50F it was pretty much silent, and this weekend it's started making a lot of noise again after the temperature ranged from about 0-15C/32-60F in the space of a few days.
There's not really anything else I can attribute the change to, I'm assuming there's a small amount of expansion/contraction in the metal parts which may not be uniform across each component - last weekend no noise, this weekend Creak-Clunk City.

Pressfit BBs are prone to creaking at the best of times. When cold, steel inside aluminium will be tighter than when warm, as the thermal expansion of aluminium is about twice that of steel. The difference is only about 0.001% per degree C, but on something the size of a BB from a cold day to a warm one  that's around 0.1mm, easily the difference between a tight fit and one with some movement.


Pedaling overhead with front vs rear hub motor When pedaling with the motor not working, would a rear geared hub motor give more resistance when accelerating or a front geared hub motor?

Given that the the torque from pedaling is applied to the rear wheel, making the rear wheel heavier might offer more acceleration resistance than adding the same weight to the front wheel (my reasoning).

Assuming both wheels are the same radius (which they usually are) and that you're not skidding (which you usually aren't), both wheels rotate at the same speed and accelerate at the same rate. So, purely in the terms you mention in the question, it makes no difference.

If there is any difference, it will come from differing designs of front and rear hub motors.


How do I tell if my cog needs replacing? Two answers to this question gather that after 14335 km (8907 mi) of cycling with a single chain, the cog is at risk of being damaged.

I haven't noticed anything unusual apart from the chain being too long. How do I tell if my cog needs replacement?

My rear cog on a Rohloff Speedhub

Different angle, close-up

The sprockets (apart from the 13 tooth) are reversible, so you can get twice the life out of one by taking it off and using the other side of the teeth. From the photo it looks to me as if it's only worn in one direction so far, or at least significantly more worn in one direction.
http://www.rohloff.de/en/products/speedhub/sprocket/index.html

(From my experience with a 3 speed hub, a hub gear sprocket can be badly hooked without causing problems when run with an equally worn chain, long after the point where a derailleur wouldn't shift properly. I'm not recommending that you let it get that worn though.)


MTB Bottom Bracket vs. Normal Bottom Bracket I am planing a Surly Trucker Disc Travel-Bike build and now I am stuck on the bottom bracket bearing. The bearing shell is 73mm wide. Is it possible to install a Sram DUB Innenlager BSA 68/73mm? I am not sure since Sram DUB is declared everywhere as MTB, can I use it and what is the difference between a MTB and a 'normal' bottom bracket bearing?

For threaded 'English' or 'BSA' bottom bracket shells, the standard was 68mm wide for road bikes, 73mm wide for MTB. However, some bikes that are not MTBs use the 73mm wide shell and there are now 100mm wide shells for MTBs as well.

By the way, I looked at the Surly Trucker page you linked to, it says the bike has a 68mm shell not 73mm.

In any case, yes you can fit that bottom bracket. It has a version specifically for 68 and 73mm  threaded shells. On a 68mm shell, two 2.5mm spacers are used so the width of the installed bracket remains the same.

You will need compatible MTB style cranks with the correct length spindle of course. Many folks get tripped up trying to install road cranks with a shorter spindle for 68mm shells into a putative 'road' bike with a 73mm shell.


Is there a good resource for helping to discern the cause of pain / soreness? I went for my longest ride of the year this past Sunday. I guess my body wasn't expecting it or my bike is slightly misconfigured. I'm interested in finding a resource where I can look up what I might have done wrong based on where I am experiencing pain. Does such a resource exist?

FWIW, I had serious stiffness and pain between my right calf muscle and right ankle.

It sounds like you want a web site similar to WebMD that you can put in symptoms and get an answer. I'd recommend against going down that route. With all endurance events, you can have resultant pain in the same areas caused by entirely different things. Trying to solve for problem (A) may actually exacerbate problem (B).

Instead, I'd recommend seeing a physical therapist or sports medicine doctor. Both can help you correctly identify what is actually injured and the PT and often the doc can help you identify how it got injured and what you need to change (setup of bike, strength in particular muscle, etc) to prevent it from occuring.

In the meantime, RICE: Rest, Ice, Compression, Elevation. Ice baths aren't fun, but they really do work.

Happy Riding!


Pedal power meters on off-road / MTB I can't easily change my crankset or hub, so I'm looking at pedal power meters. All of them (PowerTap, Garmin Vector, bePRO, Xpedo Thrust-E) use Look/Keo/SPD-SL cleats. For me, walkable riding shoes are a must.

Are there adapters from Look/SPD-SL to SPD cleats? Is there another solution to this problem?

ETA: I said I can't easily change by crankset or hub. Please don't reply telling me to do that. The reason being, I have a Pinion gearbox which doesn't take custom cranks, and I have a 158mm rear axle which hub-based power meters don't fit.

I know I am late to the party, and maybe this is too late for the OP. However, the facts have changed since the last two answers: SRM just announced a set of mountain bike pedals that are compatible with Shimano SPD cleats. The price is 1,000 Euros. The link above goes to an industry observer, and he thinks US pricing could be similar. Availability in December, 2019.

The pedals are expensive compared to existing road bike power pedals that we know are good (i.e. Favero Assioma and Powertap P2). I suspect that making MTB power pedals is difficult, because MTB pedals can take hits from ground strikes, and they're more exposed to dirt. Any MTB power pedal would need its electronics protected against all that. Also note that SRM has always been a premium power meter option, i.e. their prices are very high, and their Look-based road pedals are very costly (US$1,700 for dual sided, $900 for single-sided).

It does seem likely that other companies will target MTB power pedals in time. In fact, IQ2 (I believe it's pronounced "IQ squared") announced an MTB power pedal (also SPD compatible) earlier than SRM released theirs. The issue is that IQ2 had initially got crowdfunding for a completely different design - they were designing pods that you inserted into your cranks, and then you inserted pedals (any type) into the pods. They found this to be infeasible, and they switched production plans to road (Look compatible) or MTB pedals. They plan to charge 329 EUR for the MTB pedals, 299 for the road pedals.

However, if you read between the lines at the link, the writer seems to think it's quite possible they won't deliver at all. If you read the comments, a lot of people come right out and say that they're expecting failure. The writer (DC Rainmaker) is a long-time industry observer and commenter, and I would place a lot of weight on his opinion. Also note that his post stated that the patent on Shimano's SPD pedals appears to have expired, and this could allow existing companies to create SPD pedals without licensing fees. That could lead to more MTB power pedals soon.

To expand on @Criggie's answer, the PowerPod estimates power from wind resistance and accelerometers. I believe this is more technically complicated than measuring strain at the crank/chainring/pedal spindle and translating that to power. DC Rainmaker has some reviews of their technology, but my sense is that this type of power meter is much less developed than direct force power meters.

This was alluded to in comments in Criggie's answer, but I believe the PowerPod has to assume the coefficient of rolling resistance. That is obviously going to vary between road and off-road, but off-road is a pretty diverse set of terrain. Furthermore, detecting the transition between road and off-road may be challenging, not to mention detecting transitions between types of off-road terrain (e.g. fire road, fine gravel, rough gravel).


Could rubber parts on bike rack damage the rear shock? I have Specialized Stumpjumper Evo FSR and as all the FSR frames its' shock is underneath the top tube. Now the issue that the only option to put the bike on the rack is to put the shock shaft on the rubber U that's on the rack. The question is, can I do something to ensure avoiding scratching shock shaft? Or the only way is to get a new rack?

You can purchase a rack adapter thats primary use is for mixte, womens bikes or bike with angled top tubes. It is a removeable bar that attaches to the seatpost on one end and then attaches between the stem and the headset top bearing at the other end. You then hang the bike on the rack by the adapter.


Ultegra FC-R8000 Chainring Bolt Fatigue As per my troubleshooting to find a bike creak (Ultegra FC-R8000 Right Crank Arm Creak) - I have installed and removed the same chainring bolts ~8 times. In the process I snapped one of them. Each of my installs have used a torque wrench at 14Nm with a Torx T30 bit.

I have noticed that when installed on a crank it seems more difficult to push the T30 into the bolt, but when they are removed it is easy to slide the bit into the bolts.

Has anyone else experienced this behaviour from these (or other Shimano) chainring bolts? Am I doing something wrong if this is happening?

For what it's worth - the best answer I've been able to come up with/figure out is that when I was torquing the bolts down I might have been putting force on both the crank arm and the torque wrench and maybe doubling up on the force...


What is this ring on these bottom brackets? Ordered a few bottom brackets; I've never seen this ring before. I can imagine its purpose, but that imagining takes me to consider that this could be problematic (bottom out before bolt is tight). So - what gives and is this new?

You mean the shoulder that is inboard from the square taper?

If the crank manages to snug onto the square taper far enough that it hits the shoulder but remains loose, then the crank arm is worn and needs replacing.

The tolerances will not allow a good crank to press hard against the shoulder, so don't worry.


Blue tyres for single speed I need to change the tyres (700 x 25)  of my single speed and I am looking for some good quality tyres, preferably blue. Do you have any suggestion on what could be a good match, or where to look? Regarding delivery costs: I live in northern Europe.

This may be closed due to asking for opinion, but CST makes a tire called the Super HP in a wide variety of colors. I live in the states but am 99% sure you could find them across the waters as well. Another option from them would be the Czar:

http://www.csttires.com/int/bike/road-bike-tires/czar-c1406/

From my experience they are a decent affordable tire.


How does Slime coagulate and seal holes in tires? How do tire tube sealants like Slime coagulate and seal holes?

They can't coagulate like blood, because there's air already in the tube and they'd solidify. It also can't be in contact with moisture as there's a lot of moisture in tubes as well.

What's their sealing mechanism?

Most sealants work because they are actually a fibrous fluid or rubber solution.  When a puncture happens and the air pressure forces the fluid out a hole, the fibers create a plug or the rubber hardens.

http://www.velonews.com/2010/01/news/cyclocross/technical-faq-tire-sealants_102346


When using the front brake, should I always move my weight to the back or is just bracing with arms is sufficient? I always thought that OTB is caused by deceleration if the rider stops too abruptly. But I've found an article that says:

  Jobst Brandt has a quite plausible theory that the typical
  "over-the-bars" crash is caused, not so much by braking too hard, but
  by braking hard without using the rider's arms to brace against the
  deceleration...

And also I've found an answer, that supports this argument.

On the other hand, there are also people who say otherwise.

I'd like to read opinions, supported by actual practice or science, on that topic.

P.S.
Personally, I only use the front brake while standing on the pedals and never when I'm sitting on the saddle, so I'm more able to control my balance, shifting my weight to the back more or less and bracing against the deceleration with my arms.

What is the fastest possible way for you to stop?

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

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

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

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

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

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


Bottom bracket maintenance - is it a thing? Previously when I've had annoying noises from my bottom bracket I've simply discarded it and bought a (cheap) new one.  But the last time I replaced it I got a great offer and splashed out a little bit on a Hope Road Ceramic Bottom Bracket.  A couple of years on (but only 2,000 miles later) I'm getting noises out of it when I pedal.  Due to injury it has sat around for a long time while I recuperated.  I'm trying to avoid replacing the bottom bracket if I can.

I don't need help diagnosing the source of the noise.  Please assume my diagnosis is correct that the noise is from the bottom bracket - ball bearings or any other part of it including it's fitting to the frame

What I'm trying to understand is:

Is there some maintenance (clean and re-grease?) that I should have been doing but missed? Beyond cleaning it externally I've done nothing to the BB
Does the fact that it's ceramic make a difference to question 1?
Are the ball bearings generally a sealed unit or is it possible to open, clean and re-grease them?

My "bike mechanic" skills are self taught since I was a teenager.  Naturally there's things I find I should have been servicing all along or monitoring but simply never knew I had to (for example rim-wear).

To the bearings themselves, not really. It's possible to pull the
seals and clean/re-grease the bearings while they're still
installed, but this isn't something it's expected anyone's going to
actually do. (The one you have I believe has bearing seals that are
pretty easy to get to, making this easier to do if you want it.
Shimano Hollowtech BBs have the bearings covered by a plastic "top
hat" seal that's not intended to be removed and re-installed, and
usually can't be without ruining it.)

For all external cranks, it's pretty common to encounter noises that
can only be remedied by cleaning and greasing the spindle interface.
That might be considered regular maintenance.
No.
In general, all cartridge bearings with rubber seals can have the seals carefully removed, which is something of a skill in and of itself, be cleaned with solvent, rinse, blown dry with air, and re-lubricated. The nature of external BBs is that you won't be able to remove one side's seal, which makes the process more difficult but not impossible. As mentioned above, many external BBs have difficult or impossible to remove parts in the way of the bearing cartridges themselves, and doing anything with the bearing isn't really practical if this is the case.

Another thing that bears mentioning in this conversation is that many Hollowtech 2 compatible external cups can have their cartridge bearings driven out and replaced. Enduro and Phil both make presses just for this. What replacement bearing and seals are appropriate depend on the BB.


Creaking in rear wheel I have a strange creaking that sometimes occurs when I just started to pedal from stop. And strangely, it only happens when I use the smallest front chainring and smallest rear cog. The creak doesn't happen each revolution, only when pedalled hard or from the start. What causes this?

This type of cross gear configuration is frowned upon for normal riding. Mostly likely the creaking is caused by the extra stress caused by the chain putting stress on one side of the gears and chain. Lubing the chain and re-greasing the rear axle (if it is not sealed) could also help, as this creaking may be symptomatic that they are lacking. But the real take-away here is to avoid this type of gearing combination.


When overhauling bottom bracket bearings, is it possible to replace loose bearings with cartridge bearings? I am fixing up an old schwinn continental from the early 70s and was wondering whether it was possible to put cartridge bearings in the bottom bracket

Can you clarify if you mean a cup and cone housing, to change from loose bearings to bearings in a metal retaining cage? Like this:

ANSWER 1 These can totally be used instead of loose bearings.  There are fewer balls to carry the weight, and over time the cage may break down and get chewed up.

OR do you mean cartridge bearings with ABEC ratings like this:

ANSWER 2 No, these can't be used without major re-working of the bottom bracket.  There are adapters to do this, but they won't be cheap.

OR do you mean a cartridge bottom bracket like this:

ANSWER 3 Yes this works perfectly, is dead simple, and relatively cheap.  Plus they're greased for life and never need adjusting.  When they get crunchy, replace.  I've done this on all my bikes.


Best Cassette Cog Material I am replacing my smallest cassette cog for the 3rd time.

I have been using Harris Cyclery's Aluminum Cog

Crupi's Chromoly Cog is about 3 times as expensive. Is that still worth it?

Can anyone comment towards how much Chromoly increases the cog durability?

The key property is hardness. For uniform materials (like cogs), hardness directly affects wear resistance. The harder the metal the longer it will last.

Some digging around wikipedia suggests that typical Brinell hardness values are:

pure aluminium 15HB,
6061-T6 aluminium (heat treated) 95 HB
mild steel 120HB,
4130 CroMo steel 183-217 HB (90-96 Rockwell)

It seems likely that most aluminium cogs will be 6061 or closely related alloys, so you're looking at the steel being about twice as hard as the aluminium ones. So it should last about twice as long.

Since people generally replace the entire cassette because the smallest cog is worn, by using an aftermarket one you're prolonging the life of the rest of the cassette by only changing it when the second smallest cog is worn.

Sorry for all the links, I couldn't find a single page with all the info on it.


Did SRAM change/update their 10 speed PowerLink? On a rare occurrence this weekend I managed to completely destroy my SRAM PowerLink. So I went over to my LBS and got a new one; however, when I went to install it, it was super hard to close the link (I ended up giving up after a bit since it would only go half way).

After giving it a night and then trying again, I decided perhaps I had bent the chain links where the PowerLink was, so I bought a new chain. The chain came with the same PowerLink and I had the same problem. Eventually I got it but now I'm most likely going to need to saw it off (just kidding, will need pliers though) if it needs removing.

The only difference I can see is that they went from a gold colored plate to a black one, but it's still 10 speed (and the chain is SRAM as well). Anyone know if they have modified thickness, shape, or anything else?

The new ones for 10-speed and 11-speed are frequently single-use. I buy KMC chains and half-links these days to avoid the possibility of that happening.


Are road-bike suspension forks still manufactured, if so, where? For a few years, road bike suspension forks were used at Paris-Roubaix, but now they seem to have disappeared. Are they still being manufactured? If not, why (aside from UCI regulation) did they not persist, e.g. for cyclocross or city riding?

The Rockshox at Paris Roubaix were a Greg LeMond thing. Whatever Greg competed in a few 'out there' cycling innovations came along with him. Remember those tri-bars that gave him the aero tuck position to beat Laurent Fignon in the Tour de France? On that event he also had his own road bars that had an extra position, where the drop handlebar end plugs would be, his bars turned in 90 degrees to give an extra lower position. Anyway, it was his Team-Z that introduced the Rockshox on Roubaix. Seems that your well chosen pic duly notes his special handlebars, the Rockshox and 'Team Z'.

Greg's bars and forks were not widely adopted although his time-trial bars most certainly were. In any evolutionary process some mutations just don't work. As for the forks, the problems with them were that they were heavy, the brake touched the rim and they introduced 'sloppiness' in the front end. Imaginably these problems would be overcome but they were not. I don't think UCI regulations had anything to do with it, the product at that time was just not that good. MTB forks were a bit dubious too back then, only when the disk brake came along did the 'brake rub' problem get properly solved.

There are plenty of 700c forks on hybrid bikes from mainstream manufacturers, generally of the low-end 'Suntour' variety with a spring that does the work instead of any sophisticated oil/air arrangement.

You might want to go to a bike shop and do your own compare and contrast of the bikes with 700c suspension forks. The travel is around 50mm or so and there generally is no adjustment on them. I think Trek do a few models with them, Giant did too on the more expensive 'Expression' models. Although experiences are subjective, I found that along gravel trails the hybrid with no suspension felt better than the efforts with suspension. I wondered if the suspension was doing anything at all, it did not float over the bumps like a full-suspension mountain bike does and there was no real cut in handlebar vibration.

Here is a Suntour offering with coil spring, preload adjuster and lockout. This model is typically found on things like deluxe Trek hybrid bikes:

The brakes are V-brake, the hole in the top of the brace is for mounting a reflector and you cannot put a nice set of road brakes on there. Other versions of this low end fork exist for roller cam brakes, which you obviously do not want!!!

There are some more desirable models made by Suntour for cyclo-cross and the hybrid market with 'proper' air adjustment and rebound, maybe even remote lockout. I am not sure if these models are OEM only or if you will be able to get hold of them locally:

As for Cyclo Cross, checkout the Suntour NRX models, with disk and all the sophistication you could wish for in 700c:

http://www.srsuntour-cycling.com/dstore/products/Forks/2845/NRX/SF11-NRX+S+ELD+700C+LTD.html

That fork should give you the ultimate in comfort for the front end of your road bike. Although for cyclo-cross it has the makings of a very tidy commuting machine...


Crank Length 165mm or 170mm? mixed views I have been doing a lot of research into crank length, I have a 172.5mm crank which I find my knees come up too high, and sometimes I get a bit of back pain. I have a Scott Speedstar 2017.
I am 175cm tall, and an internal leg length of 78cm. I looked at the following video:

             which was invaluable but, I find I am around 164mm for a crank when using the 9.5% of my height.
should I go down from 172.5 to 165? or just move down to 170mm? as was said at the end of the video, "Modern bikes are designed around 170 to 175mm long cranks"

should I goto 165mm or 170mm long cranks? I know I need a shorter crank, just how much shorter is the question :)

Thanks! :)

Percentile based formulas for crank length are trash. Femur length, health or special needs of all the joints in your leg, and the desired relationship between your saddle, knee, and pedal are all factors, as are the clearance needs of the bike, the type of riding being done, and Q. There is zero reason why a simple percent of your height would suffice.
Fitters who are serious about delivering a good result are mostly going to use some kind of system (or haphazard rule of thumb) to come up with an ideal saddle setback and knee to pedal spindle relationship, then choose a crank length based on that, then test it with either different cranks or a sizing crank.
As for your situation, if going to a fitter is off the table, you are going to be much better off making your own estimation of whether 2.5mm or 7.5mm is going to be the right amount of reduction. I would make sure you're feeling very confident about your saddle height being on point first, because that's a far more common source of issues with knees being put in an uncomfortable position.
Some shops do have sizing cranks and might be willing to set you up to spin on a trainer in a corner for a while if you're going to buy cranks from them afterwards.


What are the practical limitations of a road bike compared to a mountain bike? I grew up on a big box store mountain bike. I want to get a road bike for my commute, but I'm curious about the limitations I'll experience.

I know the benefits of a road bike: lighter weight, less rolling resistance, aerodynamic riding position, etc.

But I want to learn about the limitations: I'm mainly concerned with the ability to hop up and down from curbs and occasionally riding through some mulch and grass.

Is a road bike's frame less tough than that of a mountain bike? On my cheap mountain bike, I can (though I usually don't) hop over and down from curbs at full speed. Would I have to be more ginger with the road bike or would curb-hopping be recommended against altogether? Would the drop bars make it difficult to hop over curbs at all? And would a road bike's tires be unsuitable for anything off-road? Any other limitations?

Honestly hopping curbs isn't something that I would consider as an important factor to consider in choosing a bike for commuting. Riding a road bike it's almost always faster to just stick to the road, and if you do way to exit the roadway it's rare that you will have to travel more than a few seconds before there's a driveway. Still, YMMV - I don't know your route.

Roadbike frames are fine, it's the wheels that will go first. Don't get silly 16 spoke wheels to commute on.

There are a couple of things to be aware of with a roadbike though:

crossing small rises at acute angles - with skinny tyres when you roll up a small bump at an acute angle (ie. across the edge of a footpath that is raised above the surrounding grass) if you hit it at too fine an angle your wheel will skid off and straighten out whilst your momentum continues over the bump - resulting in a stack.
bottom bracket/crank clearance is less than on a mtb - be careful pedalling through bumps/corners.


Can a guy wear a woman's helmet safely? I'm a guy and since I started wearing a helmet for mostly Trail Riding and occasionally for commuting, I noticed that the helmet looks really large on my head. My doctor later confirmed with a tape that my head is slightly smaller than average, and this explains why my helmet looks weird on me. I would like to wear a smaller helmet.

I have a couple of questions in this regard:

Are Women's helmets any smaller than men's?
If they are, would it be safe for me to wear one (assuming I can find a color I like!) ?
Are there in fact helmets for teenagers that might be useful in my situation?

I am slightly below average height and about 145 lbs.

"Women's" helmet is a pure marketing feature. All helmets have to pass the same safety standards and if it fits wear it.

Most helmet models come in at least 2 or 3 sizes. You should be able to find a helmet in the size that fits your head diameter. All the major manufacturers make helmets for every head size from 2 year olds to XL for adults. Every helmet should
have the head size range listed somewhere on the box.


Unknown shifter mount This screw goes thru the frame (downtube) to hold two shimano 7speed (indexed) shifters.
Apparently, one of the bolts is screwed and needs to be replaced.
Problem is that the guy who owns the bike doesn't know where to search since we do not know the name for this weird mount, nor when it was produced or how to get one of those.

I thought i might find help here?
Possibly an idea for how to replace it?

Update:
A friend of mine has a lathe and will just make a new bolt.

You can find what you're looking for under names like "downtube shifter lever boss kit".. You should be able to find something at a bike shop (especially one which works on older bikes) or a frame builder.

Another alternative is to use a clamp.


Proper lateral rear hub position (with spacers) What is the proper position for a rear hub along the axle? So far my understanding is 'somewhere' slightly toward the non-drive side to leave room for the sprockets - and I understand that the rim is central because the drive side spokes pull the rim to the center between the lock nuts (ie. in dish). However, I've also read that the greater the in-balance between left and right spokes, the weaker the wheel will be. Therefore, the hub position is still important.

The other factor is how the position of the sprockets are affected, as they need to line up  properly with the chainset.

Is there a 'best practise' way of determining proper hub position and spacer configuration?

(I received a comment I believe saying that when you put it all together, the hub position is right if the wheel is in dish. I was under the impression that it was the other way around - you would adjust the dish of your wheel to your hub / spacing configuration.)

This is an exaggerated drawing to help illustrate what I mean. With varying configuration of spacers, you could position the hub anywhere on the axle. So where exactly does it go?

Thanks in advance.

It really depends on the situation. You're balancing chainline, frame clearance, spoke angles, and in some cases q-factor (the distance from the pedal mounting face to the frame centerline). How you have to weigh each thing can depend on the bike and what you're doing.

It may be helpful to look at a situation where you have tons of freedom, almost too much. Let's look at the example of putting together a singlespeed road bike starting with an unbuilt standard-axle cup and cone freewheel hub, which you'll be re-configuring to run a BMX freewheel, and some square taper double cranks with all the choices you could want in spindle length.

Using a vernier caliper or rule, and measuring the best you can looking down at the hub shell with one eye closed, you make a simple diagram of the immutable points of the hub with the freewheel screwed on. Left to right, these points are the face of the left cone, the center of the left flange, the center of the right flange, the centerline of the freewheel teeth, and the face of the right cone. Mark the distances from one point to the next. (I've had bad experiences putting freewheel spacers on singlespeeds so I'm discounting their existence here.) Also measure the thickness of the hub locknuts you'll be using.

You then plug in a bottom bracket of any spindle length, put the right crank on with its chainring installed on either side of the spider, and measure what front chainline that spindle length is giving you. Then you measure the spider tab thickness, the chainring thickness, and the amount of frame clearance you have between the ring and the chainstay. Finally measure the frame spacing, aka over-locknut dimension.

In theory and usually in practice, that's all the data you need to figure out the rest.

Well put-together singlespeeds must have essentially perfect chainline, so that's your first priority. When I put together a singlespeed in this manner, usually I decide I want the wheel to be dishless (rim centered between the two flanges, so no spoke tension disparity and maximum strength due to maximum total tension). I let the q-factor fall where it will, as long as it doesn't cause a clearance problem. So the first order of business is to see what things look like to have it set up for perfect chainline and dishless at the same time. To do that, look at your diagram. If the wheel were dishless, the distance from the center point between your two flanges to the center of the cog would be your chainline. You then look at your crank/chainring/clearance data and see if you can achieve that chainline with an existent bottom bracket. Remember you measured the spider and ring thickness so you can see what each position on the crank would give you. Also remember you can use chainring spacers to fudge it up front.

If up front is good, all you need to do is set up the hub. Go back to your diagram and look at the flange-to-flange spacing. Take half of that number and add the left flange to left cone face distance. Let's call that L. Then take half of the over-locknut dimension and subtract L. From that subtract your left locknut thickness. The remaining number you have left is how much spacer you need to have on the left side. Do the same for the right, and that's your ideal hub configuration with the priorities of perfect chainline and dishlessness.

From this example you can probably see how things would change if, for example, you wanted to prioritize a certain q-factor over having the wheel be dishless, or if you only had one BB spindle length to work with and you needed to make the chainline right at the expense of the wheel being dishless, or if you were working with a built wheel and weren't able to re-dish it based on a new hub spacing or if its spoke lengths were limiting how much you could viably re-dish it. The process is the same for multi-speed freewheels and cassettes, only you get much less freedom, and in the case of cassette hubs you sacrifice wheel interchangeability once you start tweaking the hub spacing (relevant for riders that want or need to swap wheels with minimal adjustment.)

When it comes to configuring hubs, in most cases chainline is boss; it really can't be sacrificed without performance suffering so its always the first priority. The exceptions are extremely long-chainstayed bikes (like recumbents for example), where the long chain run makes it matter less, or if you have a triple and decide you're willing to make the small-small combos unusable in exchange for narrower q-factor. But there's not a lot of overlap between those situations and ones where you'll be messing with hub spacing configuration.

If one is just overhauling a rear hub and loses track of which spacers go where, it's true at that point that as long as the wheel dish was correct to start with, the spacer arrangement that makes it correct again will generally be the right one. If the wheel dish wasn't necessarily correct to start with, one will have to do some figuring.


Broken Crank Arm - Chainring Connection I was just riding my bike like normal the other day and the crank arm started slipping. Upon further inspection, I discovered the 'bolt' that connects the crank arm on the drive side to the chainring was sheared off.

What is this missing part called? How can I fix this?

I have no idea where to start with this repair... Can anyone help me? I'd love some advice on all my options from cheap to overhaul. Plus some expert terminology for all relevant parts so I'm not just saying stuff like a dummy :)

What you have is a 'one-piece' or 'Ashtabula" crank. Info can be found on this Sheldon Brown Page. They are called one-piece because the crank arms and axle are made from a single bar of steel.

The chainrings are not fixed to the crank axle and can rotate on it, instead there is a 'drive pin' that sticks out of the right hand crank into the chainring spider. That's what has broken off your crank. From the picture, I think it was press fitted into the crank and worked loose.

I did some quick googling and found that replacement arms are available and inexpensive. Your chainrings do not look worn so you will be able to reuse them (although they could use a good cleaning 😉).

If you are not experienced with bike repairs a local bike repair shop will be able to handle replacing the crank easily.

Update:

Park Tool has a good video on disassembly and servicing the bearings and re-assembly.


Riding experience of 21-speed vs. a 7-speed? I am 5 feet tall, age 63, weight about 110 pounds, and I ride mainly for exercise on paved greenway trails. I used to ride a lot and can go many road miles, say up to 20 miles, quite well on terrain that is mostly flat but I struggle on hills. My old Marin 21-speed from REI feels too heavy and I want a bike that is lighter weight, a little easier overall to ride, and may "help" me get up hills (a la Atlanta, Georgia, if you know what I mean...) without having to walk my bike. However, the Marin has 21 speeds and I like being able to choose gears. But I am thinking of the 7-speed Cannondale Treadway 3 which I tried yesterday and it rides like a cloud! Apparently the 7 speeds only allow you to pedal to a limit on flatter or downhill terrain, and then it sort of spins out and you have to coast. At least that is how I interpret what the bike shop guy said. I'd rather be assured I will get some pedaling exercise while flatter sections. Is this a good tradeoff? I don't want or need a souped-up bike and at $635 the Treadway seems like a nice buy.

Do you use the front derailleur?  It seems many people in reasonably flat areas do not.  If not, you are riding a 7 speed.  Take a ride and notice what gears you are using, particularly on the steepest climb and the steepest descent.  The lowest gear will be with the smallest chainring in the front and the largest cog in the back.  The highest gear will be with the largest chainring in the front and the smallest cog in the rear.  Your gear ratios come from dividing the number of teeth on the chainring by the number on the cog.  Now you can compare the ratios available on the new bike to what you are using on the old one.  If you are having trouble up hill, do not accept a bike with any higher a low gear.  If you want to pedal down hill, do not accept a bike with any lower a high gear than you use now.

If you are using all the gears you have, a new seven speed will either have a much narrower range of gears or much wider spacing between the gears.  The spacing won't be a factor 3 wider because the gears overlap.  If the new one has the same range, try shifting two gears at a time on the old bike.  Is that too large an increment?  If so, you need more than seven gears.


What are the advantages of flat spoked wheels? Following on from my earlier question about truing them, I was wondering if anybody could point out the advantages (and perhaps disadvantages) of flat spoked wheels?

When building or truing a wheel, it's easier to notice if you put a twist in to a flat spoke.


Building an Entry Level MTB. How should I choose suspension forks? I am new to Mountain Biking. I just bought a CRONUS HOLTS 330 (Hardtail) with Shimano gear system and disk brakes. Its a 19" frame with 26" tyres. All aluminium pretty light weight. The brakes are ok for now the only problem is the suspension forks. The forks are made by zoom and they suck. They dont spring back if they go in I have to jerk the handlebar upwards to bring them back to midway preload position. I am interested in buying a used rockshock air suspension fork but I cant figure out which ones are best for me because there are a million different types out there. Please help.

Also, the sram product matrix can be handy (y is cost, x is severity of impacts):

source: https://www.sram.com/sites/all/themes/sram_2011/st_rockshox/_images/products/product-matrix.png


Tips for radial wheel truing Several drive side spokes on a mountain bike rear were damaged the rear mech being pushed into the wheel by a rock, with one snapping completely. I've replaced the affected spokes and have managed to get the wheel (almost) perfectly true laterally.

However, I've noticed that the wheel is out of true radially -- i.e. it has high or low points of 2-3mm in a couple of places. I don't know if this was present before I replaced the spokes or not, but I'd like to improve this before putting the wheel back on the bike.

I think I need to tighten (or loosen) spokes equally on both sides at the high (or low) points to resolve this. But doing so seems to have little or no effect when making the kind of 1/4 or 1/2 turn adjustments I used to true the wheel laterally.

Am I going about this in the wrong way? Or do I need to make much bigger changes to spoke tension to affect the radial profile of the rim?

It's (a lot) harder to achieve in-out motion than side-to-side, and generally requires (much) more that 1/2 turn adjustments.  Plus you must usually loosen spokes on either side (2-4 spokes away) of a high spot, or tighten spoken on either side of a low spot.  For low spots sometimes you need to tighten ALL the spokes except those over the spot.

But at some point you need to either scrap the rim or employ a tool to bend the rim.  Bending out low spots can be effectively handled with a jury-rigged tool consisting of a couple of blocks of wood with holes drilled in them and a piece of "all thread" with a couple of nuts and washers.  (I've never dealt with high spots serious enough to require the opposite tool.)


Any small bags that mount to seat post? I am looking for something similar to a saddle bag but that mounts to the seat post and not the saddle.

I have a rear mounted camera that attaches to the saddle so want a bag that I can mount lower down on the seat post. I want to keep tubes, CO2, multitool etcetera in there.

I have searched and can't find anything.

Thanks

Maybe one of Revelate Designs Jerry Can bags would work for you.  The mount on the front side of the seatpost and would leave the rear of your seat post open for your camera.  They are pretty versatile, I have used one on top of the triangle, inside the triangle and a few other places I won't mention.


Puncture in SCHWALBE CITIZEN ACTIVE tire Does anybody know what type of tire is SCHWALBE CITIZEN ACTIVE? I have a tiny punctures in it and have no idea how to fix. May be I wrong but I think it is tubeless. Should I bring it to service or is it possible to fix myself?

Update: Tyre is attached to rim with some tape. Image below

A quick google shows https://www.schwalbe.com/en/tour-reader/citizen.html

Its a straightforward clincher tyre that may be used tubeless, but may be used with a tube.

Best thing to do is take the tyre off and see if there's a tube inside.

Do note that tubeless tyres can be run with tubes perfectly well.

From there, your question devolves to either :

how to fix a puncture in a tubeless tyre  or

to patch or replace a tube?  followed by either: how to fix a puncture in a tube tyre  or  how to replace a tube in a tyre


Do kits that allow me to add lockout to my shock exist? I have a (within last year) rockshox Deluxe R rear shock on my bike, on some hills I would like the added stiffness of a locked out shock. Do upgrade kits to add lockout exist or would I need to buy another shock?

(My bike is a 2017 Whyte g170)

Cheers all.

Lockouts are performed internally within the shock, often by closing out part of the dampener circuit. This would make it nearly impossible to create a general upgrade kit as shocks can have very different internals (even from the same brand).

The only possibility would be a lower end shock that shares its shock body with a higher end version that has a lockout feature. In this case you might be able to purchase the internals of the higher end version. Even then you may be missing components such as the lock out lever, plus the lower end version may be missing ports for the lockout lever.

Purchasing new rear shocks is another possibility, but it can be quite expensive and there are a lot of measurements to get correct (e.g., eyelet to eyelet length).

In short I don’t see any easy upgrade path.