Slight Difference in Spoke Tension Between Inner and Outer Spokes on Straightpull Hubs? I recently built up my first set of straightpull wheels, with I9 hubs and traditional DT Swiss Competition spokes. (Hubs were from a I9 Trail S Hydra wheelset and are very much like DTs.)
Something I didn't expect, but ran into, is that when finishing up tensioning the wheels, it seemed like the inner and outer spokes on each side required a slightly different tension; about 1 number on a Park TM-1 tension meter.
This seems to makes sense because the spoke holes for inner vs. outer are a few millimeters different when it comes to flange distance, and thus the inner (steeper bracing angle) spokes would likely have a slightly higher tension.
The wheels built up wonderfully and I had no problem getting to even tension, but it was a bit surprising at first because instead of having one final tension for each side of the wheel I had a (slightly) different for inner and outer spokes on each side of the wheel. For example, here's the numbers from the front wheel:

NDS (L) Inner: 22 (117 kgf)
NDS (L) Outer: 21 (105 kgf)
DS (R) Inner: 20 (94 kgf)
DS (R) Outer: 19 (85 kgf)

So my question: Is this normal?
Due to what's effectively a slightly different flange spacing it makes sense, but I wasn't able to find anything about it searching around online, so maybe it's just one of those things that's understood/accepted by more experienced wheelbuilders?
(If it's useful I have a full writeup on that build here.)

Yes, it's normal and you correctly understand why. Some straight pull hubs can create more variance in bracing angle per side than a j-bend hub would. Other straight-pull designs (Velomax/Easton comes to mind) put the spokes in a straight line, creating the least of this variance possible.
On a j-bend hub, there is also some amount of this effect. But, it's usually very minor. How minor varies with flange thickness and rim diameter. In other words, it's at its least in a road wheel (big rim, dainty flanges) and greatest within BMX (little rim, sometimes thick flanges). You see the same thing where it's almost never a noticeable phenomenon building road wheels that the true optimal spoke length varies with the side of the flange, but if you look at nipple thread engagement on most BMX wheels the difference in engagement is readily observable. In almost any case with a j-bend hub, the effect is minimal enough and the rim is stiff enough that you can have all the spokes at the same tension and the wheel will still be visually true, because the rim stiffness is enough to make it that way. But, using a dial indicator on a very light, low spoke count rim built to near-perfect tension tolerance, you will be able to see the effect on the indicator.
Another way to think about it: the classical spoke length formula reduces the wheel to a bunch of circles and triangles between points in 3-dimensional space. It doesn't account for flange thickness unless you run the formula once for each side of the flange. It also doesn't account for the thickness of the spoke, i.e. the distance between its surface and center.
In practical terms, for bikes, once in a very great while, if you build a lot of BMX or ebike wheels, the whole thing can result in running out of threaded length on one side of a flange but not the other. I've seen it a few times. The importance of understanding this effect is actually in resurgence, because small wheel motor hub rebuilds are an increasingly common shop task, and they have some of the thickest, shortest spokes on the thickest flanges of pretty much any bike wheel genre in history.


How do Traffic Lights Notice Bicyclists? This totally unrelated reply raised my question about traffic lights.

I am starting to think that my chinese head lamp is a magical instrument, every time I go near traffic lights they turn green. It is hilarious to drive in heavy-traffic and just that you get green lights! Perhaps just a placebo feeling so I want to know how your traffic lights behave to you when you are driving within other traffic? How do they notice you with/without lights?

Well, I need to explain how it works. I have head lamp with blinking white light and particularly when it is very dark, the traffic lights are clearly programmed somehow to detect the intensity variation of lights and then turn green. I have heard that emergency cars show some kind of special light to turn lights green for them. But I suspect whether the head-lamp contains some special light, it was the cheapest model I found from eBay.

There are two basic types of intersection detection systems out there:

Induction loop coils:
These are basically a metal loop or figure 8 embedded in the pavement, and will detect anything that conducts electricity. Much like a metal detector, such as you might walk through at the airport. Sometimes you can see lines carved into the road surface. Getting your wheel over the lines will help you get picked up.
Cameras: You may be able to see the cameras, even.  These are generally black and white cameras that are programmed with areas they pick up for each lane and do some sampling things and if the samples look different than the "baseline", that's a detection. If your headlamp is helping, this is the type of detector in use at that intersection. A bright light will definitely be picked up at night. Light clothes that contrast with the color of the road surface will also help.


Tern Spartan (front rack) on Bike Friday NWT Does anyone have experience with putting a  Tern Spartan™ low-riding front rack on a Bike Friday New World Tourist? Will it fit?

Tern Spartan front rack:

Bike Friday NWT

Bike Friday standard front rack

Yes, a Tern Spartan Front Rack does fit on a BikeFriday New World Tourist (and also the Tern Cargo rear rack):

To prevent the rack from interfering with the V-brakes I mounted the upper end of the rack (and the fender) on a 80mm screw. Behind the fork I inserted 4x6mm spacer (the thinner in diameter the better) to mount the rack before the V-brakes (yes, the mount does interfere with the brake's cable but since the surface of the spacer is smooth I do not expect to notice anything when braking):

As of January 2020, Tern offers two versions of the Spartan front rack. 74mm and 100mm. I bought the 74mm version. When mounting the rack to my BikeFriday NWT, I felt like the rack could be slightly wider in order to being able to mount it with less force. However when measuring the rack at the height where the panniers are mounted, I measure roughly 100 mm which I find confusing.

Some may argue that using a 80mm screw with a margin of some 30mm from the fork to attach the rack reduces the stability of the rack and the maximum loading capacity. However, to me this does not seem to be the case considering that I will not mount very high weights to the rack. I do not know if my solution also works with disc brakes rather than V-brakes.


Repairing stripped threads on a nut type bottom bracket I recently bought a used 2011 diamondback outlook mountain bike for $30 on craigslist.

The bike however needed some significant work. The bearings in both wheels need to be replaced, the shimano 7 speed freewheel was rusted to crap and best of all, the rear brakes were missing. I guess that's why it was $30. The previous owner also decided it would be a great idea to coat everything in some very heavy automotive grease. the only good thing about that was the chain was really dirty but just needed a good cleaning. Somehow that was intact...

Anyway here's what we are getting to. I was removing the right crankarm to replace it with different ones that weren't so beat up and the threads are now stripped. Not the threads inside the crankarm, the threads attached to the bottom bracket that allow the retaining nut to hold the crankarm into place.

Picture:

As you can see the threads have been almost ground down. The threads at the bottom closest to the square taper are what they are supposed to look like, and above that is what the threads look like now.

The nut also was stripped when I was removing it, so I ordered a replacement 14mm nut for this type of bottom bracket online since I can't find a nut like that in the fasteners section of my local hardware stores. But I can't easily do the same with the bottom bracket, so I need to fix it.

My first thought is to wrap some thread tape around the damaged threads. They still seem to be "sort of" there, just sanded down.

My second thought is to use a ton of threadlocker red on both the nut and the bolt, then tighten it in. This should hopefully create a good enough seal and the new nut won't move.

Third option is to buy a thread tap and try to carve new threads into the bolt. The only problem is I would need some sort of hollow thread tap that would fit over the bolt, and I don't think that even exists. I also don't know the appropriate thread pitch tap to buy in the first place.

My fourth choice is replacing the bottom bracket altogether. That will require me to buy more tools to remove the bottom bracket like a shimano bottom bracket removal tool, and costs the most. So I really want to avoid this if possible.

Finally, is it possible to remove the threaded portion of the bottom bracket entirely by unscrewing it and just install a new threaded rod? Can that even be done?

Any ideas?

The thread repair tool that is used in this sort of situation is called a die. The common size for crank nuts is M8x1.25.

However, too much material appears to be lost here for that approach to be reasonable. Crank nuts/bolts are one of the higher torque items on a bike, meaning you don't really have much leeway for severely damaged threads. Also, hardened steel threaded parts like this don't take as well to thread reformation as softer steel parts. Taps and dies have some capacity to shove material on damaged threads back into place, but here it's likely to break off instead.

You don't indicate whether you have a cartridge or cup and cone BB, but nutted BB spindles are almost always (maybe literally always?) found on cup and cone BBs. If so there's nothing stopping you from just replacing the spindle; basic cup and cone BBs generally let you do that freely since they tend to all use JIS spindles. You need the same length and, if applicable, offset. Pull the existing one and hopefully you'll find a code on it like the one in the picture. Match the new one with that. Shops don't tend to just have them anymore, since the common approach is now to just replace everything with cartridge, but they are still able to be ordered, and are cheap.


How do you switch the Raleigh RX10 rear light to flashing instead of constant Sorry for the ludicrously specific question, but I just cannot work it out!

Mostly when I turn on my rear Raleigh RX10 USB rechargeable rear light it has a constant beam. Pressing the power button again toggles the intensity of the light. Pressing and holding the power button turns the light off (or back on). Occasionally it comes on flashing instead of constant, but I have no idea how. How can I reliably and predictably turn on flashing mode?

Typical - no sooner posted than worked it out.

Pressing the button turns the light back on, but pressing and holding the button eventually turns it on in the mode it was not in last time (i.e. if it was on constant mode then pressing the button turns it back on in constant mode, but pressing and holding the button eventually turns it on in flashing mode.)


Will shimano 10 speed triple shifter work with compact chainset? Will a right hand shifter described as shimano 10 speed triple work with a SRAM 9 cassette and a shimano compact chainset?

While Shimano does have one shifter (2010 ST-5603 105) which will work with either triple or double drive trains, no 10 speed shifter works with a 9 speed cassette, at all.

There are cam adjusters which claim to correct cable pull and allow you to use mismatched equipment, but how well they work is open to debate.

You should maintain as close to matching specs as possible.  All 10 speed or all 9 speed equipment is pretty much mandatory.

Mixing brands is likely to degrade performance to some degree, although it will work, usually.

Bottom line is, if you need to ask the question, you don't have the necessary experience to make sure that everything comes out ok at the end.

On the other hand, you'll learn a lot if you try it, and if you can afford to experiment, it could be fun to try to make it happen.  Be prepared to buy everything 2 or 3 times, if you do try it.

Hope that helps.


My new mountain bike tyres with presta valves do NOT inflate I purchased a brand new bike from auction several months ago and although the tyres were pumped up a little they were not pumped up fully.  I purchased a presta valve adapter for my old pump and I know that you have to turn the little nozzle on the presta valve to allow air to go in when pumping and then you close it afterwards. HOWEVER, when I start to pump it just does not inflate and stays flat, I cant figure out why.  They were inflated  when I purchased it and the bike was brand new without ever being used.  I keep pumping but my tyres just stay flat. Strange one for me even though I last rode a bike about 15 years ago but surely things have not changed that much have they?  Please help as with the lockdown I cant even go to a bike shop to show someone. I tried pumping them several times on different days with the same result - still flat. Remember they were inflates when I got it and its been kept in my garage nice and safe from harm.  Thanks

Some Presta valves can accept stem extensions and the upper valve body (containing the little nut you unwind to add air) can be unthread from the lower part to accept extension. Anyway, this sometimes comes unthreaded with the use of a presta  to Schrader adapter and air is lost. Perhaps this is loose and air isn't getting into tire/tube but escaping here. There are tiny wrench flats on the upper valve body of many Presta stems. If present in your case, try snugging it up.
Another problem might be at the pump. Some hand pumps require a lever in the correct position to deliver air into the valve. Make sure you fully engage the valve and if the pump has a lever try both open and closed positions (here I mean lever up and lever down positions).  Hand pumps that can switch from Schrader to Presta set-ups utilize the lever in opposite positions for filling depending on which system you're doing.  The limited # of ones I've seen, the lever is placed "up" or 90 degrees to the pump body when in Presta mode. So with the lever down (parallel to pump body), you fully engage the open Presta valve and then lift the lever to the 90 degree position and begin pumping.
A presta tube can be partially inflated with your mouth, should you choose, by pushing the unwound valve tip with your tongue whist you blow into it. You can check the valve integrity this way. I recommend a cold beer with that dish.
My guess is your pump end is not engaged correctly or is faulty.


iPhone app to follow/navigate an imported .gpx Is there an iPhone app that allows one to follow an imported .gpx track, in a car navigation-like way?

The apps I found so far, like Trails, can only display the track on a map. What I am looking for is a "download-and-forget" experience for my bike trips. I want to import a track and just look at my iPhone to tell me in which direction is the next waypoint, or how can I get back on track if I get lost.

http://www.motionx.com/ is the closest I've seen. You can set it's map to show track up as you ride. It doesn't know where the roads are though, nor zoom in or out depending on your speed, nor show upcoming turns.

NOTE As of 2019, this app is now end-of-lifed. It was great while it lasted.


Are there any recumbent tricycles that can be transported with a normal car? My wife would like a 3 wheeled recumbent, but I can’t see how we can transport one with a normal car.

I can put my bike on a rack or the roof, but all the recumbent I have seen are too large to transport.

What solutions have people come up with?

If your car doesn't have a trailer hitch on it, you can have one installed and purchase a "trike and bike" rack that mounts in the trailer hitch receiver:

Hitch Rider Trike-N-Bike™ hitch mounted racks transport a trike and bike at the same time. Wheel holder and bike support arm styles are available for the bike carrier position. The rack fits both 1 1/4" and 2" vehicle receiver hitches (patented).

My inlaws ride recumbent bikes and had a hitch installed on their Toyota Camry and purchased a double-trike rack.


How does one extrapolate riding calories to fellow riders? A 30-kg child, a 60-kg adult, and a 90-kg adult go on a bike ride.
The 60-kg adult uses a cyclocomputer, which knows the weight of the adult—and gender and age, as well as the weight of the bike.
At the end of a ride, the cyclocomputer declares that the trip used 1000 calories.
Would it be accurate for the 60-kg adult to declare to the child and to the other adult that—if we were to ignore gender + age differences, as well as the difference in bike weights, which may well be serious omissions—that the child has just spent roughly 500 calories and the adult 1500 calories?
Two cyclocomputers may not even agree on the estimation of calories, and so this question only seeks a very rough "ball-park" confirmation whether the relation is linear.
In short, do cycling calories scale near-linearly with weight?
Since older children are typically quoted as needing 1500 calories per day, compared to an adult's 2000, before factoring in exercise, might we use this to expect that a child is using 75% of the calories during exercise as well?

No, calorie burn does not scale linearly and can vary based on a great many factors.
Calorie consumption is very closely tied to power output.  Power in watts x4 is usually considered a good estimate.
If the entire ride was on a steep climb using tyres with virtually no rolling resistance, then in this case you would be correct.  However on a real ride other factors come into play (rolling resistance and aerodynamic drag).
In terms of rolling resistance, there is a large variance between tyres - or even between the same tyres at a different pressure.  This will also change (but not linearly) with rider weight.
Increases in body mass also do not lead to a linear increase in aerodynamic drag.  Further to this, power output can change a lot due to a riders position and clothing.


When should a disc brake be replaced? I've had my bicycle for about three and a half years. I use it just about every day, for a total of 30 kilometers of commute a day. The problem is that my disc brakes have started making weird noises when braking. For the front one (less used), it's a shrieking sound, and for the rear one it sounds kind of like a gremlin or someone clearing their throat.

I suspect this has to do with disc brake wear, so that leads me to the question; after what distance traveled or time used should you replace a disc brake?

There is no way you can accurately assign a distance to disk brake replacement.  Someone commuting in a stop and go method in a wet climate like the pacific northwest will get much less life out of their setups than someone living in a drier/cleaner climate and a more continuous commute.

Anyone can determine the relative life left in their setup by looking at their brake pads.  The pads are the wear point for a set of disc brakes and DO need to be replaced with normal use.  Almost all other aspects of the system are likely to last near indefinitely with normal use (except perhaps the cables on a cable actuated system).

For your part, you would do well to check you brake pads IMMEDIATELY.  If you wear all the way through the pads and do not replace them you have a high chance of ruining your piston as well as possibly your rotor.  Ruining the piston will essentially result in needing to replace the entire caliper and/or unit.  Hopefully the horrible noises you are hearing are just the pad backing tearing against your rotor and you haven't damaged your pistons yet.  You may get away with just new pads and/or rotors.


Would like to find out what is the brand of this bike I am rebuilding? I know is chromoly frame, and serial number starts with 8D30D334... I will add pictures, if anybody can help would be great...

Edit from a later post:

Yes, I found out that the tires had been replaced and many other parts.  And yes the tires were close to 35 or 33. We even had a hard time fitting the front wheel, the wheel seemed to be big for the fork.  It came out pretty nice. I will try to post some pictures.

The plastic part was a torn up reflector.

I ended up giving it to wife, and got myself a new Specialized Hardrock 29 MTB, and I am riding every day an average of 10 miles.

I have no idea what brand it might have been.  And really the brand means little.

From your two photos I see 90s hybrid bike brazed with lugged steel (not welded like I originally said) - you can see the bronze around the bottom bracket.

Dunno if the flat bars are original... the single rear derailleur looks a bit odd mounted on the quill stem.  Normally they'd have thumb shifters.  And that orange shift cable outer looks decidedly weird looping up at the back chainstay.

The wheels may not be original either.  There appears to be a relatively large tyre on both wheels, at a guess 32mm or 35mm ?  The mud/colour makes it hard.   Schrader valves imply larger tyre widths too.  Quick Release skewers also implies no older than the 90s.

There's a bulbous bump in the seatpost - does the bike have seatpost suspension?

There's an odd plastic thing on the seat pole just below where the stays are attached.  Not sure of its function.  What is it?

The crankset looks relatively modern - I suspect this has been converted to a single chainring at some point.


Gear shift wire on SRAM after an accident Took a pretty good fall after narrowly avoiding being hit by a speeding driver in the middle of a two lane road.

Managed to get the chain assembly back together but can’t figure out where this wire goes. Please see the following picture

https://imgur.com/a/sJMwhVJ

It should run something like this, and be pinched under the washer behind the pinch bolt. judging by the scratches on your derailleur (if they are from the fall), it's pretty likely that your derailleur and/or derailleur hanger are bent.

SRAM has pretty great manuals @ service.sram.com if you know the model of your derailleur that should include cable routing.


How do I degloss my shiny bike? I have a Tomasso Sterrata.

I love the bike, but I don't love the paint job.

I think I would like the paint job more if it weren't so glossy. (This year's model has a matte finish of course, but I have last year's model.)

What can I do to give it a more matte finish without covering up the existing color and decals?

If you really want to paint it, you can try to wetsand it to remove the clear coat, and then refinish it with some matt finish clear coat. This is a risky move if you're not experienced with painting cars or stuff. You can ruin your bike real quick.

The safe method, and easiest one, would be to wrap the bike with some matt/satin finish clear vinyl (here is an example). It is often used on cars by people with the same issue as yours, and would perfectly do the trick on your bike. Plus you can remove it whenever you want, and it will protect your frame. It's a win-win.


Can I use WD-40 on my bike? Is WD-40 really bad to apply on bikes? I was told so but still see people doing that.

Also I saw WD-40 launching their new products of bike lubricant and degreaser. Did anybody try those?

WD-40 is mostly a solvent with a very light lubricant mixed in. It's great for getting stuck parts moving again. When you spray it on, the solvent dislodges whatever gunk may be causing the part to stick and then evaporates, leaving a light lubricant behind. This will allow the previously stuck part to move again.

The reason it is generally not considered a good bicycle lubricant is because it is a light lubricant. It's just fine for household items like door hinges, which aren't exposed to weather and don't get moved a couple hundred times a minute. But the lubricant is not thick enough to adhere to rapidly moving bike parts for any length of time, especially when you add a little bit of road grit and/or rain.

Some people do use it for loosening up shifters in the winter time (they stick when it's cold) or cleaning chains and derailleurs. You will notice in the answers and comments on the aforelinked question, and this one, that whether or not this is good practice is highly debatable. Some people will use WD-40 as a cleaner and degreaser followed by a bicycle-specific lubricant, with or without a cleaning inbetween, depending on personal preferences.

I don't have any experience with their bicycle-specific products, but they're a solid company that's been in the business of cleaning and lubricating mechanical parts for a long time. They also make Lava soap and 3-in-1 Oil, a product that was originally designed as a bicycle lubricant (although they did acquire both of those from other companies). I actually didn't know until I read this question that they were making bicycle-specific lubricants now. Given their history and the number of patents that they have to draw ideas and develop from, I'm certainly willing to give them a shot. The worst case scenario is that I have to clean it off and go back to my previous products.


Can a freewheel hub be swapped out for a cassette hub? I have a very cheap, yet very old, 26" Chinese rear wheel with a freewheel hub mounted on my MTB. The hub, bearings and cones are shot, but the rim is still good.
I have two Shimano cassette hubs FH-RM20 and FH-RM50, that I got very cheaply on eBay. I was hoping to get the freewheel hub swapped for one of the cassette hubs at a local shop for 160 baht (~£3) - labour is cheap in Thailand.
However, after originally having said that the hubs could be swapped, once I had taken the cassette hubs to the shop to show them, the lady in the shop has now told me that the hubs could not be fitted. Due to language issues, I wasn't given any explanation as to why.
The number of spokes is the same (36) and the spoke holes diameter is 45 mm in both the freewheel hub and the cassette hub, and the spoke bases (i.e. the holes for the spokes) are 67 mm wide (or rather, apart) on both types of hub. So, the fit (i.e. dimensions) would appear to be the same.
I am not sure whether the shop was expecting my to want to swap for another freewheel hub, and having the cassette hub instead is the problem. So, my questions(s) are:

Is it possible to swap the hub types, or
Does it lead to other issues, such as offset issues? Can the same spokes not be used?

I am tempted to just try to swap the hubs myself and then go back to the shop to get the spokes tightened properly, but I don't want to mess up my current wheel if it is not possible - the bearings may be shot but it can still get me around (just about).
Keeping costs to a minimum is a priority, hence why I am not going for a new set of Formula hubs, AlexRims RM19 rims and Pilar spokes for ~3000-4000 baht (~£70-100), However, I don't want another cheap Chinese hub, so that is why I am attempting this hybrid solution of a good cheap second hand Shimano hub and the existing cheap rim.
Please note that this is a different question to Can I convert freewheel hub to use cassette?, as I actually want to swap hubs and not convert them.

FWIW, I currently have a 7 speed freewheel gearset (Shimano MF-TZ07), and I have a Shimano CS-HG41-7ac to use for the cassette.

You say the bike is old, and a 7 speed freewheel hub can be 126 or 130mm over locknut dimension, and the cassette hubs you have will be 135, so that could be one mismatch they saw. But most freewheel hubs on 7-speed bikes from the past 30 years or so have been 135.
Other than that, what you propose should work. The shop might not have realized a conversion of this sort is usually not a big deal.
Note that the flange to flange spacing alone is not exactly what's important. It's the center to flange dimension on each side. Sometimes this is expressed by giving a flange to flange dimension plus an offset dimension, which accomplishes the same thing. But that said, between the hubs in question here, the center to flange numbers are probably almost identical barring an OLD mismatch as above.
Dropping in a new(er) cassette on an otherwise worn drivetrain can cause issues with skipping under load. There are many questions here about this. The shop could have decided to balk at getting into those potential issues.


Why are the rear wheels of time trial bikes disc shaped rather than having spokes? Won't having disk shaped wheels cause more wind resistance with crosswinds? What are the benefits of having these sort of wheels?

Disc wheels have lower drag than spoke wheels.  See Wheelbuilder aerodynamic data and Aerodynamics of High Performance Race Bicycle Wheels.  (One link shows simulated data, the other measured).

Most of these tests run up to yaw angles of 30 degrees.  The argument is typically that at higher yaw angles (closer to side-winds) the rider would choose a spoked wheel instead of a disc.

Disc wheels are typically preferred for courses and days that do not see a lot of cross-winds not because of drag, but because they present a large area for the wind to push on, and can lead to unpredictable performance in high-crosswinds.  This is one reason you don't often see disc front wheels in a non-velodrome environment.


How do I stop my EBB (Eccentric Bottom Bracket) from creaking? I have a '09 Felt Niner 29" SS with an EBB. After a thorough clean and reassembly of the BB the creaking will subside for a ride or so and then come back. Any suggestions?

EDIT: the problem appears to be dirt getting into the bottom bracket area. The combination of sweat, water bottle drip'age or post ride spray down results in dirt getting into the BB area. The only way I can see to prevent the creaking is to somehow seal off the exposed face of the BB preventing dirt from getting inside.

Your mileage may vary, but this has worked for me.  Try using some telfon tape around the outside of the EBB before you put it in.  It's cheap and you can get it at a local hardware store in the plumbing section.


New inner tube bulges near the valve when inflated I've installed a new inner tube in my wheel. I checked the tube doesn't make a knot. When I inflate the tube, it bulges near the valve, and this rubs against  the brakes.

REF tube: 32/47 609/642

REF tyre: 42-622 700 x 40C

What could be the cause of this (wrong size of inner tube?) and how can I fix it?

PS: I'm not sure if it's a dup of Uneven inner tube when inflated inside the tyre?

Thanks.

Unless the tire bead (the re-enforcing wire around the edges) is damaged your tire is simply not seated on the rim properly near the valve and has popped off as the tube was inflated.

Tube size seems OK. 32/47  possibly means it's compatible with 32-47mm tires. If it's about the same as your old tube that it's OK.

Deflate the tube and re-seat the tire. It's probably a good idea to get one side of the tire off the rim and make sure the tube is installed correctly too.

There are many good videos on YouTube that show correct procedure (try this one). but some key points:

Make sure the tube is not pinched between the tire and rim.
Make sure the reenforced valve area of the tube is pushed up into the tire
Make sure the tire is evenly seated on the bead all the way around. There is often a line moulded into the tire around the bead that lines up with the rim you can use a a reference.


Is using hand signals a legal requirement in the UK? I am just starting to cycle on the road and I'm wondering if cyclists are legally required to use hand signals or if they are optional (i.e. recommended but you won't get into trouble if you don't use them).

Sometimes I am able to signal but other times I cannot signal without risking falling over. Is it OK to ride without signaling provided that I am careful about making sure that drivers understand my intentions in one way or another (e.g. slowing down, looking in a particular direction, moving across the lane or starting to turn) or do I have to stay off the road until I can signal more confidently?

They're in the highway code, but the word "must" isn't used in the online version or my paper copy from 1999, which states:

Turning right
155. Well before you turn right you should
Use your mirrors...
Give a right turn signal

A cycling-specific rule is 52 in my copy (67 in a more recent edition):

52. You should

look all around before moving away from the kerb, turning or manoeuvring, to make sure it is safe to do so. Give a signal to show other road users what you intend to do.

We could argue about whether the should applies to giving a signal -- it certainly would if it was in the first sentence of that bullet point, or a bullet point in its own right, but we dont need to: in the context of the highway code, context must means a legal requirement, while should means if you don't and there's an accident you're likely to get at least some blame.
So no, you're not obliged to.
In fact, in one of these cases (moving away from the kerb) I tend not signal -- because I wait for a big gap, then as the vehicle at the front of the gap passes me, I accelerate hard, with both hands on the bars for control and changing up through the gears.  Signalling after it's passed wastes some of the gap, and theres often no room to signal while it's passing (signalling before it passes would only confuse its driver).
However if there might possibly be traffic about, it's a really good idea, especially signalling right, as that means you're about to move into the path of faster vehicles.  If you're right handed this may take some practice.  So practice somewhere quiet; you'll soon get the hang of it. Try riding left handed with your right hand near the bars, for example. Until you can confidently signal right there may be cases where the only way to go right safely is to stop and cross like a pedestrian.
Never ever assume that drivers react to you looking round.  Hardly any will notice, and they may take their eyes of the road to see what you're looking at.  Even with helmet lights that clearly indicate me turning my head (red rear, amber sides) I've often been overtaken while getting ready for a right signal.
Drivers don't understand cyclists' speed.  You're going so slowly from their point of view that you'd have to be down to walking pace for them to notice.  Moving out into the lane can help.  But you need a good couple of hundred metres gap and visibility even at 30 mph -- I'd signal then too.
A comment on my answer to a related question confirmed that a slowing down signal is very rare.  So don't worry about that one.


Trek 1.1 Derailleur Hanger I've got a 2011 Trek 1.1, and my derailleur hanger broke in a crash a few weeks ago. I've tried both a number 5 and number 6 hanger, which are what WheelsMFG has listed, but neither seem to fit. There is not any damage to the frame, so I'm at a loss as to why these won't fit. The old derailleur hanger is chewed up, and I can't make out what number it is.

Can anyone suggest a better hanger that I can buy?

After calling around to a few different Trek shops and buying several different hangers online, I took my bike to a shop near me that specializes in commuters and things like that.

The mechanic took one look at it, ran to the basement, and came back up with the correct hanger. It is a Wheels Mfg. #49.

I explained to him the trouble I had trying to track down the right hanger, and how it is listed incorrectly on the Wheels Mfg. site. He told me that this hanger in particular is common to a lot of Fujis, so his guess was that they were all made in the same factory, just under different brand names.

Anyway thanks for all the help and research, I'm glad I finally got this resolved.

TL;DR: Wheels Mfg. #49


Are road bike shifter hoods compatible across models? I've been using Shimano Sora Shifters since about 2012 .. probably one generation before the current
(https://bike.shimano.com/en-EU/product/component/sora-3500/ST-3500.html)

The rubber covers are now corroded and slimy so I want to change them, but I am not sure if they are available for an old model. I’m wondering if I use a cover for a different model, how likely will it be compatible?

Anyone familiar with this?

Thanks in advance :)

In general, shifter hoods are not compatible between models. Campagnolo has had three different designs since the 90s and Shimano has had many more. If you know the exact model and year of your levers, you should be able to find both original and third party replacement parts online. Competent online stores should have a selection of hoods and list for compatible levers for each.


RPM regulation of direct hub motors I found this bike push-trailer.

Because the trailer project is open-source I discovered that the used hub motor is MUXUS XF40 (specs here)

In many places on the internet a learned that if such motors doesn't runs at their optimal RPM (usually high) they could get overheated.

Because the trailer could work in 2 modes:

6 km/h engine support in Hand-Car-Mode
25 km/h at 250W in Pedelec-Mode

I wondering how is possible to manage the "hand-car-mode" where the hub-motor runs very low RPM (max. 6km/h) without overheating or other problems. Or the "low rpm overheating" isn't real issue and it is possible easily a safely regulate the BLDC motor to run in any LOW rpm?

adding to Chris H 2018-04-30 post... I'm going to take a stab at some basic math...

BLDC motors can put out their rated power at high RPM partly due to air cooling enhanced by the high RPM (like computer chips, if you add active cooling, they can go even faster... it's all about how much heat they can dissipate).

At lower RPM the motor gets less air cooling as a by-product of the RPM, so it dissipates less heat, even though it might be delivering the same amount of power (pulling more weight).

However, if you're pulling the same weight at 6 km/h as at 25 km/h, you're going to be drawing a lot less power out of the motor for mechanical work, so it'll be generating less heat and probably not need to dissipate heat from RPM-based air-cooling, to keep the motor windings from melting their insulation or the wires themselves from fusing.

I'm new to BLDC controllers, but if there's one that allows you to set an RPM-biased torque limit, or RPM-based power limit on the throttle, you could protect your motor from thermal overload. You could chart a few operating ranges or give it a function with a curve to limit torque or power according to RPM. At 100% rated RPM, it could use 100% power. At 75% RPM, 75% power. At 50% RPM, maybe 40% power, and at 10% RPM, maybe 5% power.

A simple thermal cut-out might be a bummer if it happened while toting a heavy load up a hill in hand-cart mode. If the controller just limited motor power, you might be able to keep going.

If you've got a motor rated 1000 W at 1500 RPM, it might be rated 250 W at 100 RPM. At the higher speed, it's doing 1000/1500/60 Watt-hours of work per revolution, or 1/100 of a Watt per revolution. With 250 Watts at 100 RPM, it would be doing 250/100/60, or 0.042 Wh of work per revolution, so it could be moving a load 4x as heavy, and 1/15th the speed. (1/4 power applied to 4x the weight should get 1/16th the speed, I guess?, but I had rounding in my calculations above).


Realign the cassette gears after removing the rear wheel I took out my wheel for a puncture and when the wheel went back on the bike the gears were out of line, a lot of skipping and jumping. What is the best way to get them back in alignment (must be possible at the road side)?

Is there a tip on how to reinsert the wheel so it stays in alignment? Or is it a case of getting the wheel back in and adjusting the derailleur to realign?

(On a road bike with tiagra rear d)

Normally, when removing a rear wheel, I shift to the small-small combination since this gives the most slack and gets the rear derailleur out the farthest. (Obviously, this doesn't matter for a front wheel). Then, when putting the wheel back on, put it on in the small-small combination and shift out of it when you've tightened the wheel down.

You need to make sure your wheel is seated all the way in the dropout. If you have horizontal dropouts, this means all the way back up to the little set screws which tell you how far back to put the wheel (you don't need to re-set the set screws). For vertical dropouts, this means all the way up in the dropout.

If the wheel was in properly and the gears were aligned before removal from the dropout, they should be still aligned when you put the wheel back in. In the case that the wheel isn't aligned properly, either your derailleur took a hit at some point, the wheel/tire is somehow hitting the brakes, or most likely, you didn't put the wheel in the dropout properly. (I suppose frame damage is also a possibility, but this would have been something you noticed before removing the wheel)

Try re-seating the wheel in the dropout. If you're sure you've got it in the dropout correctly, follow the instructions on adjusting your rear derailleur here.


Possible Broken Shifter My right Shimano shifter is now loose and clicking it doesn't do anything to the rear derailleur. I've checked the derailleur and it still works fine. How can I fix the shifter?

Edit: It's a road bike cable shifter; it has the brakes with it as well so it's a brifter (?). I have potentially found the problem. Something in the cable seems to have snapped as the cable has come out of the shifter. Any way to fix that?

Edit 2: I realised that someone shared a link on how to replace the cable in the comments so this question has been answered. Thank you everyone.

Based on the edit, put a new cable on. And while you're at it, you may as well replace the cable housing.


Can a conventional seat be reversed 180 degrees to be used as a noseless seat? I am interested in potentially switching to a noseless seat (also called noseless saddle). Instead of buying one, can I simply reverse my conventional seat 180 degrees and sit on the edge of the new front (the former back) of the seat? I will only make contact with the new front of the seat, while the former nose (the new back of the seat) will just be there behind me and not be used or cause any harm.
I tried doing this on my bike and riding it for about a mile total, stopping periodically to adjust the angle of the seat and distance of the seat from the handlebars (sliding along the rails). So far, it feels consistent with descriptions I have read of using a noseless seat. I have included some photos.
I am interested in:

Feedback, opinions, and analysis about this possible strategy.
Somebody who has access to both a noseless and conventional seat testing out this strategy to see if the backwards conventional feels similar to the noseless. Please only do this if you feel safe and comfortable testing this out and also are interested in answering the question.

Other thoughts or possibly-relevant information:

If I decide to use this possible solution permanently, I would find a conventional seat that is the correct width for my sit bones, which I have gathered is an important part of finding the right seat, regardless of whether it has a nose or not.
I use my bicycle for commuting, going to the store, and similar outings, with round-trip distances in the 5-15 mile range.
I am not asking if a noseless seat is good or bad. That topic has already been debated a lot online, I have noticed. I understand that some riders consider noseless seats to be a threat to safety and a gimmick solution to a problem caused by poor bike fit, while others consider noseless seats to be better for their health and comfort.   Instead, taking it as given that I want to try using a noseless seat, I am asking if this reverse-seat is a viable option, because to me it seems no different than many noseless seats out there already (for example, if you take the portion of the reversed conventional seat that I would sit on and saw off the rest, it appears to me that we would end up with approximately same thing as the moon saddle advertised at https://www.moonsaddle.com).

Photos:

If it works for you then go ahead.
The risk might come in a lack of control when riding hard, like descending while off the saddle it is common to use the sides of the saddle against the inside of one's thighs to help control the bike.
Separately you might need to angle the nose up sufficiently to get a comfortable position on the now-leading edge
Lastly, its probably not an issue for you but a reversed saddle on a rental bike means this one is damaged and needs some kind of service so don't rent it.


Is the same effort required to maintain a set speed using different sized chainring / cog combinations with same ratio If I have a bike with the same cranks setup with a 36t (chainring) / 12t (cog) ratio and the same bike setup with a 48t (chainring) / 16t (cog) ratio, would the effort required to maintain a set speed be the same for both setups or is there some small difference created due to the size of the chainrings? This assumes a 3:1 ratio on both cranks.

Would there be a difference in a geared versus single speed (no derailleur, same chainline) configuration?

Here are some points taken from the literature:

Mechanical efficiency is usually 88-98% for majority of deraileur systems (when clean,lubricated and new)
Drivetrain efficiency decreases with smaller rear cogs,
Highest efficiency can be reached at high torques and low cadence,
Chainline effects are negligible, imposible to note with measurement apparatus,
Higher efficiency can be obtained with a single-speed as opposed to derailleur use, and there may be a few reasons for this.
Efficiency of an internal gear hub is generally lower than this of a derailleur system*

So in your case it's likely that the 48/16 setup will give a slightly higher mechanical efficiency. Also once you've gained the desired speed higher rotational inertia of larger sprockets will help keep the speed at slightly lower effort. On the other hand lighter and smaller sprockets will make it easier to accelerate. However all these changes will be barely noticeable on the road, and especially when the drivetrain is already worn.

Some research has been done in the past on this topic, and there are also pages like this one, where the data on resistive forces within the drivetrain can be bought..

*Reference: Wilson, David G. Bicycling Science 3rd ed. 2003. p. 342-344


Is the balancing easier on big cycles after the kid learns to ride pedal less bicycle? Is the balancing easier on big cycles after the kid learns to ride pedal less bicycle?

Kid is 2 years 8 months old. Is this a correct age to go for such a cycle?

If they are steady on their feet and tall enough than a balance bike is fine.
The advantage of a balance bike is it develops balance first as small children don't necessarily have the strength or co-ordination to ride a pedal bike to begin with.

We found the wooden balance bikes to be inherently bigger - so for our child we went with the much smaller dimensions the aluminium balance bikes.


Is my pump faulty or my tyre? I have recently bought a Specialized women's road bike and for the last couple of weeks was borrowing my boyfriend's hand pump with no real issues.

Last night I finally purchased my own (Topeak RaceRocket HP) but each time I try to inflate the tyre (just a top up of air, not from flat) I can either hear air hissing out (I believe the pump isn't screwed on enough then) but even a quarter of a turn too far means the pump won't work as the air pressure seems to be too much and this would suggest I've screwed it on too tight. Just can't seem to get a happy medium.

It could be resolved with a floor pump but as I've just dropped £30 on this, I want to be sure before I spend another load of cash just to eliminate possibility.

Any suggestions? Should I return the pump or am I doing something wrong?

Thanks :) x

As other have commented since you can fill the tires with another pump the issue is not your tires. If you bought it at your LBS (local bike shop) I would bring it in and have them demonstrate its' proper use. If they  can't get it to work they should replace it at no charge. While the listed capacity is 160psi, the amount of effort required to generate the pressure will vary with pump design. A larger diameter pump will require fewer pumps to inflate a tire but with more effort. While not as much of an issue with a floor pump the difference can be considerable with a small pocket pump.


Wheel axle thread size What size nut does it take to fit the rear wheel with a nexus Shimano rear axle? I measured the axle size and I'm getting 9.2mm. or .360 in.

Most likely you need:
3/8" diameter
26 tpi (thread per inch)

On the website below there is a list off all Shimano gear hubs which use this size nut:
https://www.sjscycles.co.uk/hub-spares/shimano-nexus-brim40-cap-nut-38-inch/

Please check if your hub is listed to ensure compatibility.

Source: https://forum.cyclinguk.org/viewtopic.php?t=98948


Rear derailleur breakages This is hypothetical in the spirit of a recent question about derailleur cables, but I've seen two bikes being pushed with broken rear derailleurs in the last few days.

What are likely causes of broken rear derailleurs (commuting /road especially; I assume that in MTB it's hitting stuff). Alternatively what can we do to avoid it? I've worn one out but never broken one.

Perhaps more importantly, if a rear derailleur breaks on the road, what can a rider do, and what tools would they need?

If a derailleur breaks on the road, you can try to find a gear combination such that the chain can be stably placed on a given chainring and cog and shortening the chain to fit on this combination. This question gives some guidelines on how to select that cog and chainring. Note that you should also check the wheel for damage -- depending on how the derailleur goes, you may de-tension some spokes or do other wheel damage. You basically need a chain tool and ideally a quick link/special rivet to shorten the chain.

In Video form:

As for why derailleurs break on the road, I'd say wearing out, being out of adjustment, bent or taking an impact would be reasonable causes. One can avoid some of these by not putting the bike derailleur side down and avoiding impacts to the derailleur.


Will my commute get easier? I cycle 20 miles total per day, on 3 or 4 days week, commuting between work and home.

Will this get easier? as stupid as it sounds.

I start work at 6:30am and can't drive so I cycle until I can afford a moped and cbt training (?). Right now I find it mega hard in the morning.

I bought a new hybrid bike with slick tires etc. I go at easy pace and take about 50 minutess each way.  I suppose I am looking for encouragement as will need to do this for least another 2 months. And I have a few heavy inclines to battle also.

I am 32 and not really fit.

My personal experience: I (re)started biking on commute last October, 26 km both ways.

Though I believed I was not rusty (I was able to cycle 80 km in one day without complaints), the first few weeks it was really demanding. I was able to cover the one way trip in somehow 45-50 minutes, and when it was Friday I could feel really empty and craving for rest.

Now I do the same distance in 30-35 minutes and it has become my substitute for morning coffee.

Long story short: your body needs time to get used to the routine and also to the different post-effort routine. Try to keep a constant pace until you get used to it, and then try to push your effort a bit further. In this way you won't get worn out.


Can I upgrade a Hercules Dirtrider 26" with gears and a disk brake? I found that dropouts are needed for derailleur setup & fork space>120mm...can I install any hanger or weld a dropout to the frame?...and also the fork end gap was around 105mm in wheel fitted condition.Can I equip 5 or 6 speed gear set in my mtb? if yes can I also mount disc brake?

The derailer is sort of the easy part. Your frame could take a claw style derailer like this:

Or you get one of these and have a lot more options:

120mm is the minimum rear spacing for derailer multi-speed rear hubs, so you would probably need to spread (bend) the frame.

You'll also need a new rear wheel, chain, and freewheel. Your cranks will probably not give workable chainline with a multispeed freewheel as they are now, which usually means toying with the BB spindle length, which is a pain on cottered cranks, and would probably also have you either removing the chain guard or finding a way of spacing it out.


Specialized Rockhopper derailleur hanger needed.....which one? I need to know which drop out hanger I need for this Specialized Rockhopper.
Part of the frame is chipped at the dropout but it will still bolt on. I just don't know which hanger I need.

I googled "specialized rockhopper derailleur hanger" and one of the links was

https://media.specialized.com/support/0000004464/0000004464_CG0421_hanger_fit_chart_rev2013.pdf

The Rockhopper table is on page 4 of 9 and looks like this

ROCKHOPPER
2011 2011 Rockhopper M4SL 26"/29er 9895-4021
2010 2010 Rockhopper SL            9895-4021
2011 2013 Rockhopper M4 26"        9895-4021
2006 2010 Rockhopper HT            9895-4021
2011 2011 Rockhopper Comp 29” HT LEFT  9898-4240    RIGHT 9898-4245
2010 2010 Rockhopper SL 29”        9895-4021
2008 2010 Rockhopper 29” HT LEFT   9898-4240
2008 2010 Rockhopper 29” HT RIGHT  9898-4245
2011 2013 Myka HT 29”              9895-4021
2008 2013 Myka HT 26"              9895-4021
2005 (Late) Rockhopper HT          9895-4021
2004 2005 Rockhopper HT            9894-4206
2003 2003 Rockhopper HT            989-4271
1996 2002 Rockhopper HT            989-4261
2003 2003 Rockhopper FSRxc         989-4271

So, with some exceptions, half of them use 9895-4021 which looks like this:

And is mostly in black with the odd silver one around.

The earlier models all use different hangers, so you'll need to remember when you got it, and work out its age from there.

Interestingly, wheel size seems to be unrelated.

EDIT OP says its a "specialized hanger 12" which seems to look like this:


If chain/ BB/ casette are dead can chainrings and derailleurs still be OK? I bought a brand new bike last May (2015 Brodie Elan) and proceeded to put 11,000km on it by November (cross Canada ride plus some commuting).

Around the 11,000km mark I brought it back to the shop and they checked the chain wear, using some sort of spring-loaded Park Tool, which indicated that the chain was totally dead as well as the cassette.

I'm not clear if the chain wear gauge directly indicated dead casette, or if it was more "if the chain is this worn the casette is definitely dead too". Either way this did not surprise me as I had been experiencing some gear/ tooth hopping that I could not correct with cable tension adjustments. I asked them to replace both casette and chain.

After getting the chain and casette off they found the bottom bracket was also dead. This also was not surprising as I had been experiencing some "gravely" feel while pedalling.

So they replaced chain, BB, and casette. However, they said the derailleurs and chainrings still had life in them and did not need replacement.

I'm wondering if that makes sense, i.e. would derailleurs and chainrings be expected to long outlast chains and casettes with which they were purchased? Or should I be worried that those could be in a heavily-worn-but-not-quite-dead state that in turn would be wearing out my new chain and casette faster? How would I check?

For reference, here is what was originally on the bike when new:

CRANKS: Shimano Deore 26/36/48T
CASSETTE: Shimano Deore 11-30t
FRONT DERAILLEUR: Shimano Deore
REAR DERAILLEUR: Shimano Tiagra
BOTTOM BRACKET: Not published but I'm guessing low end Shimano

Thanks.

The load is spread across more teeth on the chainrings than on the cassette, so they tend to last quite a bit longer.  If they said your chainrings are fine, then they are probably no problem.  derailleurs don't really have many parts that can wear out. There isn't much load being placed on the jockey wheels, so they can last quite a long time. The spring which returns the derailleur when shifting should also last very long. There's no reason to assume that the wear on the cassette, chain, and bottom bracket, would mean that the chainrings and derailleurs are about to die.

That being said, if you are planning on doing another long cross country tour, you might want to replace them ahead of time. I wouldn't want to be stuck in the middle of Saskatchewan trying to get replacement parts.  If you're just going to be doing short trips there's no reason to replace these parts prematurely.


How to clean the front derailleur? After years of usage, the spring of my FD does not return it to the smallest cog any more. Obviously, the FD has collected grit/dirt in its joints and the cage is jamming.
I do not see a way to clean it: joints are on rivets, not screws which could have been removed for disassembling. Any recommendations?

The little riveted points you mention are pivots, there are a bunch of them. What you can do is spray a little lubricant in each pivoting part of the derailleur, then physically move it side to side by hand a number of times and it should loosen up. Pull it towards you and then push it back, 10, 20, 30 times.
It might take a bit of force to start with and additional lubricant into the moving surfaces will flush out the dirt. Front derailleurs are quite simple mechanisms so a) you shouldn't damage it and b) if this doesn't get it moving then it is probably past it.
I've seen this numerous times with old/dirty and in particular, underused derailleurs. if someone has a triple chainset but doesn't use the smallest ring, for example, then the FD can easily seize up in time.


Tourney drop to flat bar conversion Is it possible to convert a drop bar road bike with 2x7 Tourney brifters to flat bar using Tourney rapidfire shifters? I believe they only come in 3x7 variant, so is it posible to use that and just limit the front derailleur? Will this even be compatible?

You have to consider compatibility between the shifter/brake lever units and:

Rear derailleur
Front derailleur
Brake caliper

Rear derailleur should be fine, Shimano uses the same cable pull ratio for everything 9 speed an below.

Front derailleur is probably OK, although I'm not familiar with Shimano's schemes for front derailleur cable pull ratio.

Brakes can be problematic is there is generally a difference between the leverage ratio in the levers and calipers for 'road' style U-brakes and MTB V-brakes.

Even if you can work out the compatibility issues, the cost of replacing the bars and shifters can be significant compared to the purchase cost of the bike (especially at the Tourney level). Sometimes selling the bike and purchasing one more suitable for your needs is the better way to go.


Are these compatible bottom brackets? I have a LeMond Big Sky SLT & an Opus Triton. Every bikepedia-esque site I went on said they had incompatible bottom brackets.

When I actually read the brackets today the LeMond has a BSA. The Opus only states: BC1.37x24.

BSA has the same measurements: 1.37x24 (according to wikipedia.)

Does this mean the crank from one will fit in the other or am I missing something?

I've read a lot about all the crank differences and compatibility issues etc but frankly I can't identify what I have to know if they're different.

Matching BB is one of the hardest jobs as a paper exercise compared to eyeballing them side by side.  As suggest in @Batman comment, length and offset are both critical, yet most sellers only specify length.

As far as matching Cranks go, there are a  number of systems - square taper was (an probably still is) the most common - there is some confusion over the compatibility between a couple of different standards, but it does not seem to be a problem in reality. Spline cranks come in a couple of different flavors, which are incompatible. Have a read of Sheldons webpage on the subject.


What derailer hanger do I need? (screw on derailer is bent) I'm hoping for some help with repairing my bike. My derailleur hanger snapped recently. I think it should be easy enough to replace with the right advice.

I have a picture of my previous hanger. It has 3 pins to attach to the frame. Does it matter if the replacement one looks the same yet only has 2 pins? Are they fairly universal?

If it looks the same like, this one on wiggle, would that mean they are the same? (i.e. the holes don't come at different widths apart?)

When my derailleur snapped, it came off with a lot of force and ended up bending a screw. Again, image attached. Can anyone tell me what this screw does and if being bent will be an issue? Also is there somewhere I can just buy a replacement screw if it's important and I can get it out. I would rather not have to replace the whole derailleur.

With respect to the bent screw, it's called the 'B-screw' and yes it is important.

The pivot in the derailleur where it attaches to the hanger is the 'B pivot'. The screw adjust the spring tension and controls how close the top jockey wheel comes to the largest sprocket.

Assuming your derailleur was adjusted correctly you can leave the bent screw in place temporarily.

Online bike stores in the US don't seem to list replacement b-screws (or derailleur limit screws), but they would be a standard metric screw or bolt size (Googling bike discussion forums seems to indicate M4), so you can get a replacement of the appropriate length at a hardware store. A stainless steel one is probably a good idea.


Which removal tool do I need for this 16t bottom bracket? The bottom bracket that you see in the picture has a strange 16 teeth profile (3-1-3-1-...).
I had this bike built a few years ago and I don't remember what model the BB is. I wonder what removal tool I can buy to remove and replace this BB.

I will list other components around the BB, which may help to identify the model:

track Miche Primato Advanced crankset (JIS)
Mash Work frame with BSA BB threading

Edit: After dismounting the BB, I have its manufacturer/model information: VP Components VP-BC73.

Looks like a typical 20 tooth (Park Tool BBT-22/32) tool should do the job. I'm not sure why every 5th spline is left out of this cup design, but visually the spacing looks the same.


TRP HY-RD adjustment Really struggling with these brakes now. Just installed new pads, but pistons won't separate far enough to put the wheels back in. Tried pushing the piston in using a  plastic tyre remover, but no joy. It seems like one pad (hub side in both cases, front and back) is a lot further out that the other, which suggests sticky pads.

I'm also a bit confused as the pistons move (both pistons on both brakes) as soon as the actuator arm starts moving. I thought they were supposed to have a delay as a valve closed, so I'm wondering if they're actually properly set up at all. I can't see where the bleed valve is though, and if it's opening.

Any advice gratefully received!

Edit; I think there's three problems I'm working on here;
i.) The pads are asymmetric; the outside pads are barely showing, the inside ones are protruding by about 2-3mm.
ii.) Even with the cable detached and the arms locked out I can't push the protruding pad in. It moves slightly under extreme force, but moves back after the force is removed.
iii.) The pads move as soon as the brake lever moves, which I don't think is right.

I'm going to try and clean the edges of the pistons I can get to, as following this you tube video

             and see if that helps at all, will report back.

The big thing about this brake that differentiates it from everything else is you must not under any circumstances use the barrel adjuster to do anything but take out slack from the cable. If you use it to pre-actuate the arm, or in other words to take up pad gap, the brake stops working right. The automatic piston advancement doesn't work correctly anymore and I believe this can happen too.

This is the whole reason they have the lockout knob on the arm. You engage that, pull the cable tight, undo the lockout, and the automatic pad advancement should take care of the rest of the adjustment. The pistons will then also be able to be retracted manually when needed.

So what you should likely do is undo the cable anchor, push the pistons back in as you were attempting to before, screw the barrel adjuster all the way in to its starting point, engage the locking knob, pull the cable tight with a plier, anchor it, and then use the barrel adjuster to get any last little bit of slack out such that when you pull the brake lever, the brake arm immediately starts moving, but not so much that the brake arm's static position is away from its own starting point (you can test this by trying to engage the lockout). Squeeze the lever a bunch of times and the automatic pad advancement should make the system firm up.


Anyone know who made this bike? See head badge pic Can anyone help identify this Bike? I could not find a manufacturer stamp or date only the headbadge and Suntour accessories. Thank you.

The badge was used by Raleigh on their Rampar (Ralpar in the UK) range from 1972 until at least the early 1980s.

Velobase shows this exact badge about two-thirds of the way down the page and says "1970s".
The Headbadge shows the design in use as a seat tube decal from 1972–82.

I found this with a Google image searches for something like "vintage bicycle R head tube badge". I struck lucky just as I was about to give up and post a comment suggesting you do the search.


How to position a bike for work without a stand I want to tweak my gears, from time to time: Adjust my front and rear derailleur limits, see if the shifts are smooth, make small adjustments on the cable tension, and so on.

Is there any way to get the bike in position without help of anyone?

I don't want to spend money on a bike stand.

In my experience, most light work can be done with the bike stored upside down (standing on the handlebars and seat). Of course, I'm assuming that you're talking about a road bike. Other bikes, like a mountainbike with a twist-shifters or trigger-shifting, might not be as well suited.


Tires won’t come off rims Help!
Have a Diamondback Release with Schwalbe Hans Dampf tires on Blanchard rims.  Couldn’t break bead to get tires off as I wanted to convert to tubeless, even after trying tire levers for an hour with hot soapy water as a lubricant. In the end, I had to get a bike shop to do it for me.

Is this a common problem with these rims or tires.  This isn’t good.  What if you were trailside and needed to work on your tire? Is there a tire that would come off using your hands without having to take rims to dealer?

It may be that your rims are "tubeless ready" which means they have a lip around the side that the tyre slots into which makes an airtight seal but does make them harder to get off. You should be all right if you let the tyre down completely and then push the edges of it towards the centre with your thumbs to pull it out of the slot. Once a bit of it's free the rest will usually pull out easily.


BBB chainring will not fit As a follow up from my previous question I decided to change my Campag Veloce 53T chainring. I bought a BBB 50T chainring. I tried to fit it over the weekend but it wouldn't fit.

I think the problem is that the original chainring is about 3mm thick where it bolts to the crank arm and the BBB one is 4.5mm. Below is a photo showing the gap where the chainring will not sit flush against the mounting points, and a diagram attempting to explain where the problem is.

I've had a look at Campy tech docs and can't find anywhere specifying the width of the chainrings at that point. I assume the BBB one just isn't compatible. Or have I missed something?

When Campagnolo introduced their 11 speed high end groupsets they re-engineered the chainset and introduced 'Micro Precision Shifting' and that new bottom bracket design amongst other features. Whilst they were at it they put the new (and thinner) chainrings on the 9/10 speed groupsets, including yours. Not that yours is compatible with 11 speed - you would have to replace the chainrings for that.

And yes, they have created a bewildering array of parts that are a compatibility minefield, making one suspect Shimano are not so bad after all...

Your BBB chainring is for the earlier 9/10 speed systems and sadly won't fit. Your best option is to put the 53T back on there until you can devote the man-months needed to research, afford and buy a genuine 50T Campagnolo MPS chainring.


What could cause an inflated tire to be "untrue" on a true rim I just bought a new set of tires (Continental UltraRace 25-622 700x25c) for my bike, which has rims Rigida 28 x 1 5/8 x 1 1/8 - 700c.

When I inflate the inner tube (both a Schwalbe 28" 18/28-622/630 and a Bontrager 27x7/8-1, 700x18-25c, and for both sizes to pressures 2 and 4 bars) the tire doesn't inflate in a symmetric way. The final result is that the whole of the wheel is not true (i.e. a perfect circle) even though the rim is.

What could be the cause for it? The natural answer would be the difference in size between rims and tires, but the old tires (Wolber 25_622, 700 -25c) didn't have such a problem.

Thanks in advance for your help!

Three posibilities:

The tire is defective (least likely).
The tire is simply not settling onto the rim properly.
You managed to twist/pinch the tube while installing.

If you twisted/pinched the tube then there will be low spots, where the tire does not seem to inflate fully.  If you suspect this, of course, remove and reinstall the tube.

If you're convinced the tube is not twisted, slowly inflate the tire while you inspect the junction between tire and rim, all around on both sides.  (There is generally a rib on the tire sidewall positioned such that it will be about 1/8" from the rim edge all around when the tire is perfectly centered.)  With your hands, "work" the tire one direction or the other to keep this distance equal all around as you slowly inflate.

Sometimes tires are hard to get seated properly when new (because, eg, they were hanging on a hook in the shop for months), but quickly "take a set" and are no trouble if you have to dismount/remount the tire later.

I'll add that sometimes the problem is that the thickened portion of the tube near the valve has gotten caught between the tire bead and the rim.  This will prevent the tire bead from seating on the rim hook properly in the vicinity of the valve.  The solution is to completely deflate the tube, then press the valve most of the way in with your finger while you manipulate the tire in the area of the tube.  This should cause the "captured" part of the tube to work loose.


How to train for Cyclecross Races I bought a Cyclecross Bike last year because I wanted to race. I did not get the bike in time to participate in any races last year though. The training course is closed near me for now so I can't train for the time being. I have looked on youtube and watched races and on how to stop in a race and the bunnyhop.
 How do I be ready for the races(that start in September) both physically and mentally?
 What should I eat before a race?
 Is there any equipment you would suggest?
 Are there any strategies I don't know about?

Your training should really focus on three main components:

Fitness
Technique
Mental
Equipment

I ranked mental third, not that it should be considered near the end, but that getting the first two components in order should give you the confidence needed to tackle the third.

1) Fitness

As long as you can reasonably handle the bike, your fitness will be the most decisive factor.  There are three main fitness components:

Threshold power.  This is essentially how much power you can hold for an hour (the length of most CX races).
Sprint power.  This is used to sling shot yourself out of the corners and to grunt up short steep climbs.
Running.   For the times you are not on the bike.  You should try and get in at least one run every week leading up to the season.

2) Techniques

Mounts and dismounts. Practice these, lots! Depending on the series you may encounter many obstacles demanding a dismount. Proficiency here will be a big benefit.

You can practice this on a grass field, walk beside the bike and practice dismounting then high stepping over the saddle and onto the pedal in one smooth motion. Your dismount should should leave your cranks level with the right pedal forward, when you re-mount you want to smoothly step over the saddle and onto the right pedal clipping in and pushing down in one smooth motion.  This takes practice. you may also need to improve hip flexibility.  The ideal should be that you step over and into the bike with your right leg.

Once you can do the remounts smoothly at a walking pace, you can up the speed and start to practice the flying re-mounts. The technique is almost identical, except you land on the inside of your thigh and slide down your thigh onto the pedal.  You do not want to crash onto the saddle (if you value your reproductive organs).

In terms of dismounts almost everyone now uses a single dismount technique (there used to be a could different dismount techniques (e.g., stepping through on the dismount side) but these are inconsistent and high risk). The safest dismount is unclipping your right leg, bringing it over the tire and around to the outside of your left leg.  You will then unclip, landing on your  right foot.

Sliding the bike You will also need to get used to sliding the bike through slippery corners.  This can take some getting used to. Often unclipping the inside foot and being prepared to tripod can help, but unclipping slows down getting back on the power, so if you can avoid it then great!
Riding sand and mud if you have never ridden either on skinny tires (i.e., 700x33 not mountain bike tires) then you will need some practice. You will need to get your weight over the back wheel and let the bike float. You can only guide the bike in the general direction of where you want to go, its pretty hard to pick exact lines in the sand and mud.
Riding off-camber corners these are tricky, especially on wet muddy grass. Its really about learning how far you can push things until the bike slides out. You need to experience it to know where the limit lies.
Sharp corners many courses can have a number of short, sharp turns. Practice these, with special attention to carrying as much speed as possible through the turn and accelerating hard out of the turn.
Picking lines this includes picking the smoothest line through rough terrain as well as how to setup and execute both sweeper and sharper corners
Riding steeps many courses will have some short climbs that are almost wall like.  Practice riding these so you know ahead of time what it takes to climb these and whether or not you can climb. If not, you will need to dismount and shoulder the bike.
Shouldering the bike. There are about 3-4 ways to shoulder the bike which are optimal under different conditions and for different body types.  A youtube search should help there.
Carrying the bike.  Sometimes you only need to carry the bike a short distance (e.g., over barriers).  In this case shouldering is overkill. Here practice dismounting, then carrying the bike by the top tube. Make sure the saddle is to the outside of your arm, otherwise you will jam the saddle under your armpit limiting how high you can lift the bike when running over barriers.
Gear selection. Practice gearing down to an easier gear before a sharp corner so you can accelerate hard out of the corner. Similarly you need the correct gear before short sharp climbs.

3) Mental

A health reminder that this is actually all just for fun!
Realistic Goals
Visualizations prior to the event
Honest, non-judgemental assessments post race of your strengths and weakness.  This is a good life skill for many things. If you have a tendency for self-doubt or negative talk try not an let it enter here, its not particularly constructive and could be a bad habit worth kicking.

4) Equipment

How to set your air pressure. This is easily one of the most critical bike settings. The lower you go, the more traction you get, but the higher likelihood of getting a pinch flat or damaging the rim. If you are running tubeless you want to reduce the pressure until you start folding the tire over in corners, then adding just enough pressure to stop it from folding.
Tire selection - because CX is so traction limited choosing the right tire can pay huge dividends.
Keeping your bike in good running condition. Pretty self-explanatory.  If the wheels are rubbing the frame and it doesn't shift gears properly, it will be pretty hard to race.


Are Shimano jockey wheels compatible between groupsets, provided same speeds? Recently my Shimano 105 (10 speed, RD-5700) jockey wheels have started squeaking during shifting, so they'll be getting replaced.  I'm thinking about moving up to Ultegra jockey wheels for the ceramic bearings/bushings, but I don't know if they're compatible.

What are the general factors that define compatibility?  Is it more than just tooth count?  Anything specific to keep an eye out for?

They are often compatible between different companies. Certainly between different groupsets of the same companies. The manufacturer normally states where they can be used and often that is multiple systems (like both Shimano and Campagnolo, some provided spacers may need to be used and may only work for some range of speed counts). Of course, if you buy a Shimano product, they will tell you it is for Shimano only. 10 speed Shimano should be compatible with other 10 speed Shimano.

But before replacing the wheels, I would try to service the current ones. I think 105 generally has pulley wheels with bushings. They can be easily services and likely need that more often than pulley wheels with bearings. How to do that is in the video below

You can of course consider ceramic bearings but the jump from bushings to any sealed bearings is likely more important than the jump from metalic bearings to ceramic bearings.


Recommended budget waterproof jacket I'm a bit baffled by the large choice of cycling waterproof jackets. Could someone recommend me a good budget waterproof jacket?

A bit more information:

I mostly ride off road
About £70 (approx 112 USD) is the    maximum I'm willing to spend
I'd like
to buy something I can wear all year
round

All jackets have to do two jobs:

Stop the water (rain) getting in.
Let the water (sweat) get out.

While being easy to transport when not in use.

£70 is unlikely to buy you a jacket that works well doing both if you pay full price.  I would look out for a Paclite in a sale, as they are light and take up very little space on wqhen not in use.

However remember that the jacket is as much about keeping you warm when you stop for a break as it is about keeping you dry while you cycle.  So maybe just have a wind proof top for when you are riding and a cheap none-breathable jacket for when you are resting.


Chain going out of the assembly I bought a 21-speed bike. The rear gear at 1st position puts the chain at 2nd toothed-wheel. Likewise 6th position puts at 7th wheel. When at 7th position, it goes out of the assembly. This problem started after a few rides. Can anybody help me out?

Your rear derailleur is out of adjustment, possibly because it was knocked against something. There are already many good guides to derailleur adjustment on the internet, so I'd rather link to one from one from Park Tool than write another one. If your derailleur has been knocked badly out of alignment, you might also need to realign the hanger.


Which the function of this "thing" (photo) in Shimano XTR SL-M952 rear shifter? Well, I bought this shifters (Shimano XTR SL-M952) and during the cleaning I found this curious detail in the rear shifter body (integrated to the clamp).
What is the purpose or function of this thing?

There was a remote shifter available for ST-M952 and SL-M952 and some others of the era, so you could shift from your bar end. It actuated the main shifter via cables and housings. This is a stop for the housing.


How do I make sure my bike's the proper size? I recently received a used road bike. I took it to a bike shop where they told me the seat and handlebars had to be raised for my height, so I had them make the adjustments. I now have trouble getting on and off my bike, and when I have to stop my feet barely touch the ground. Would these be indicators that my bike's the wrong size for my height?

While in the saddle, your feet should not touch the ground and your leg should be almost completely extended at the bottom of the pedal stroke.  You ought to be able to straddle the top tube fairly easily with your feet flat on the ground.

Sheldon Brown's article on starting on a bicycle may help with getting accustomed to having the seat higher than you are used to.  Do visit his site to see the video, but here are the basics:

  Stand astride the frame, both feet on the ground.  Do not try to sit on the saddle while the bike is stopped, this is not usually possible if your saddle is properly adjusted.
  Rotate the pedals so that the pedal for your less skillful foot is 45 degrees forward of straight up.
  Put your foot on the high pedal, then press down hard, and mount the bike as you begin to move forward.


Replacing Spark 720 2015 derailleur + hanger using markings Broke my rear derailleur a week ago along with the hanger.

On my Spark 720 year 2015, the old hanger said 142-RWS12 IDS-SL so I ordered a new one from eBay:
https://www.ebay.com/itm/SCOTT-23528...-/291980522554

Bought a new Shimano XT RD-M786 derailleur from a local shop. Both say "Shimano RD-M786 VLA" in the recess.

The parts fit together but it's clear that the reach of the derailleur will never reach the largest sprocket no matter how the adjustment screws are set, so my suspicion is that I've got the wrong hanger for the frame+derailleur combination, despite the markings being the same as the old equipment. The derailleur can't reach as close to the wheel as needed.

Which is the correct hanger?

Derailleur hangers are typically made from a flat plate of alloy, and are not bent to position the derailleur in or outboard.

I'm guessing, but if you have the correct hanger I suspect you have it mounted on the wrong side of the frame. Googling the serial number for images of the hanger I see the hanger mounts on the inside of the frame and there is a matching plate that mounts on the outside.

The google images I found seem to match online images of the Spark. If your replacement hanger looks like those you probably have the correct part.


How to measure frame size kids bike The way I know how to measure frame size is by measuring from the center of the cranks to to top of the seat tube.

I ordered a 16" bike from Halfords but the seat tube is only 9". On the box it says 16" x 9" what???? sso where does the 16" come from?

So my neice is 115cm tall. According to halfords size guide a 16" will be fine for her since her daddy has got her a 14" but thats in london.

Is it me thats order the wrong size or has the oem packed in the wrong bike?

Youth bike sizing is traditionally done by the wheel size. Check your tires they may say 16".

Other possibility is the 16" is top tube length (from center of seat post to center of headset traditional measurement)


Is there a front derailer clamp diameter that is near 29.6 or 29.7mm? I have a 1966 Schwinn Super Sport that I bought without a front derailer. The seat tube clamp diameter (i.e., the diameter measured out outside the seat tube, where a derailer would go) is ~29.6mm. Sheldon says the standards are 1 1/8" (28.6 mm) and 1 1/4" (31.8 mm).

Am I correct in assuming this is some Schwinn-specific diameter that predates those standards? I'm sure I could shim on a 1-1/4 in derailer, but I just want to make sure I'm not missing something obvious that would fit without shimming.

Looks like Saint Sheldon was right, but elsewhere.  http://www.sheldonbrown.com/schwinn-braze.html says under 1962 to 1978: Schwinn Fillet Brazing In the Bicycle Boom

  The fillet-brazed CrMo frame construction of Schwinn's second class of lightweight bicycles - the Superior, Sports Tourer and Super Sport - was unique. The production flow for these bicycles began with frame fabrication in the handbuild part of the Chicago Schwinn factory; a low-volume production area. Frame tubes were mitered in a jig by machine, and then the remaining fabrication work (brazing, filleting, braze-ons, and finishing) was done by hand. The seat and down tubes, as well as the top tube on the largest frame sizes, are slightly oversize at 29.5 mm in diameter. Schwinn called this tubing "1 1/8 inch diameter."

You will be hard-pressed to find a new FD for cheap these days.    Modern components tend to be more 31.8 or 34.9 mm.

Your best option will be to find a used 28.6mm on ebay and carefully file the clamp to fit your tube profile.  A 25.4mm FD would just need a lot more filing to achieve the same fit.

A less-pretty option would be a 31.8mm clamp and then shim it out with a lot of additional material, but that will be uglier, and potential flex under tension will make shifting worse.

You could also use a braze-on adapter and a separate FD mech.


Are aerodynamic rims worth additional weight? I was under the impression that reducing the weight of your wheels is important. However, I'm noticing that many of the extremely high-end aerodynamic rims are actually heavier than cheaper rims by the same manufacturer.

For example:

Easton's relatively entry-level EA90 SLX wheels clock in at 1398 grams and around $1000 for a pair, while their super high-end EC90 TKO are 1545 grams for twice the price.
Mavic's Kysrium Elite S wheels are 1520g and less than a third the price of their high-end Cosmic Carbone 80 wheels at 1640g.
Zipp's 30 Clincher cost only $850 for a pair at 1655g while their 808 Firecrest® Carbon Clinchers cost $3000 and weigh 1730g.

Obviously the prices seem to support the idea that aerodynamics matter more than a few hundred grams of weight, but at what point does the added weight offset the gain? Or is the importance of reducing rotational weight overstated?

Obviously the prices seem to support the idea that aerodynamics matter
  more than a few hundred grams of weight, but at what point does the
  added weight offset the gain?

An exact calculation will depend on the total mass of you and your bike, your speed, the wind, its angle, whether you're climbing, on the flat, or descending, and the speed you're going (or the power you're putting out). However, we can make ballpark estimates of many of those variables to get an approximate answer.

Let's say the aero wheels add 100 grams of total mass compared to the "stock" wheels, and in return reduce your drag area, CdA, by .005 m^2. That's a ballpark improvement for a reasonably aero wheel compared to a standard box rim, though for extremely well-designed wheels you can see perhaps double that difference (~ .01 m^2) or more, especially at high yaw angles.

The power equation for a bicycle is well-understood and was given in this Bicycles Stackexchange answer. Thus to determine the point at which it is preferable to trade off lower weight for aerodynamic drag, we can substitute suitable values for mass, speed, slope, and so on, and plot the power savings, as is done here.

The figure below compares an 80 kg rider plus bike with standard box rims vs
an 80.1 kg rider plus bike with aero rims. We presume the aero rims save .005 m^2 in drag area compared to the standard rims. Three dotted lines show the power savings for a climb of 5%, a flat road, and a 5% descent. The x-axis shows the speed of the rider in km/h, while the y-axis shows the savings for the lighter wheels -- when the dotted line is above the solid horizontal zero line, it is better to have lighter wheels; when the dotted line falls below the solid horizontal zero line, it is better to have the more aerodynamic wheels.

As you can see, only for steep climbs at low speed is it preferable to have lighter wheels; however, for this particular comparison of weight savings and aero drag savings, the benefit is small, less than a watt. As speed increases, the dotted line eventually dips below zero and it becomes better to opt for the aero savings.

That was for a steep hill. On the flat and for descents, you will almost always be better off with the more aero wheels.

Note that the savings in power is still relatively modest. When racing, even small benefits can accrue to determine victory or loss, but for normal recreational riding you may want to keep the magnitude of lighter wheels vs more aero wheels in mind, especially if your budget is limited. Only you can decide whether the relative benefit is cost effective.


I can't inflate tire. Should I look for another pump? Hello to everyone in the community. I used to own a mountain bike which used 26" tires and I was able to inflate them after changing the tube while on the road. It wasn't perfect but allowed me to keep riding.  I have since switched to a road bike which uses narrower 700 tires and so far everytime I have tried to inflate them I find it impossible to do it properly. The pressure is just not enough to ride the bicycle and I am forced to just hire some professional to fix it. Has anybody experienced this? At  1.79m and 64kg I am certainly scrawny but I was thinking maybe with a different pump I could be able to inflate the tires.
Anyway, thanks for reading and any advice will be much appreciated.
Peace

Most average small/hand pumps are in the 'high volume, low pressure' category. That means they have a big air chamber and are good for inflating a high-volume tire like on a mountain bike with a relatively small number of strokes, but once you reach a certain pressure, often in the realm of not enough for a road bike but maybe around enough for a hybrid, it can become impossible or impractical to go further. Small/portable pumps that work on road bikes do exist. Traditional frame pumps are one example, as are the "mini floor pump" type like the Topeak Road Morphs and its copies. There are also some decent true road mini pumps these days; the Lezyne Road Drive is one that works well. Of note is that many road mini pumps have proven to be basically bad products that don't work very well, and all of them, even the good ones, share the characteristic of needing a high number of strokes and being generally on the tiring side to use.

Most people with road bikes settle on having a floor pump at home, which makes it easy to reach high pressures because your body weight is behind it, and then carrying either one of the above options or a CO2 inflator. If you need a new pump and can only get one, one of the mini floor pump variety is often a good choice, because of the portable pump choices they're the easiest to reach full pressure with, plus they usually have gauges (which most portable pumps don't.)


How to maintain platform pedal bearings? I have a pair of Redline platform pedals with plastic end caps and I notice one of them does not turn freely.
They look about like this:
http://www.redlinebicycles.com/uploaded/dynamic/430/124564-thumb_800.jpg, except there is no notch near the end cap, which makes me think it isn't maintainable. The Redline page says they are available either as sealed bearing or loose ball and perhaps these are sealed?

I'm thinking about popping the cap off the end anyway and see if I can grease it.  Will I ruin my pedal?

Some pedals are designed to be disposable, with sealed bearings as you mentioned. Usually these have a plastic dust cap (the cap you referred to) which is not easy to remove. If this is the case, you won't be able to do anything with the pedal, even if you get the cap off.

Typically, as you seem to know, if a pedal is designed to be serviceable, there will be some obvious way to remove the dust caps (i.e. wrench flats, special tool socket, etc.). The lack of any such feature makes me think that they aren't serviceable and likely have sealed bearings.

No guarantees, as I have never taken the cap off of one of these pedals to find out, but I don't think you can outright ruin the pedal just by taking the dust cap off. If the pedal is already not turning freely, then I don't see any harm in taking a look.

I see two possible outcomes:

Pedal has sealed bearings and will need to be replaced soon anyway, regardless of whether you damage it further by removing the dust cap.

OR
Pedal has loose bearings, so you can clean and re-grease the parts, then put it back together.

In either case, you should be able to just pop the dust cap back on afterwards.


What is the relationship between tyre pressure and weight? To give an example of what I'm trying to understand:

To accelerate to a given speed or maintain that speed with a tyre pressure of e.g. 100PSI requires a certain amount of energy. If that amount of energy is held constant, and the tyre pressure is dropped to e.g. 80PSI, how much lighter would my bike need to be to attain / maintain that speed.

What prompts my question is the observation that many cyclists who commute have under-inflated tires, yet have paid a premium for aluminium over steel.

It's not about energy to accelerate the bike to speed, but the energy to keep it there. For bicycles the kinetic energy is a small part of the total power output of the rider (typically under 10m/s = 36km/hour and 100kg, and e=1/2 m v² = .5 * 100 * 10² = 5000J or watt-seconds. So a casual rider putting out 250W could reach 36kph in 20 seconds, assuming no friction)

The relevant factor is rolling resistance, not weight. On a flat surface there's a more or less parabolic relationship between tyre pressure and rolling resistance. The region you're talking about is the low side of the curve, where more pressure in the tyre gives lower rolling resistance. The losses here are mostly from deforming the tyre, so riding underinflated is costing you money in increased tyre wear as well as time through riding slowly.

There's also a relationship between total weight and optimum tyre pressure. Vittoria have an online calculator and there's a simpler one here with a link to the papers it's based on. Basically, more weight means more pressure and it's not a linear relationship.

To answer your question, then: assume we're in a linear part of the curve just for simplicity{1}, with 80/100 of the pressure you need 80/100 the total weight. Assuming an 90kg rider with a 10kg bike = 100kg total at 100psi, that means you'd need a -10kg bike to keep the same rolling resistance at 80psi (90kg rider -10kg bike = 80kg total). Or alternatively, starting with a 90kg+10kg at 80psi bike, you could carry an extra 25kg at 100psi and have the same rolling resistance (100kg * 100 / 80 = 125kg).

From experience though, increased tyre wear is not a big factor. At one stage I was only riding about 8-9km each way to work so I dropped the tyre pressure on my slick tyre MTB to compensate. Tyre lifetime was still determined by tread wear and didn't seem to drop - it definitely wasn't halved, for example. Bike handling was compromised a bit and I did get more punctures (n~3, though)

{1} this is obviously not true, but it makes the maths possible. The real curve is very complex and specific to a particular tyre. It's also affected by road surface and riding style, among other things.


Retrieving Loose Nipple from Inside Rim So I have a wheelset that I really like, only problem is the first time I rode the wheels a nipple came off the spoke when I launched off a speed bump going downhill.  For a long time it was silent (the nipple must have been stuck in some stan's or something) but recently its come loose and rattles all over the place when braking.  I am pretty sure this is going to drive me crazy.

Looking for strategies that people have found successful for getting a nipple out in this situation.  I figure if worst comes to worst I can take the tire off, remove the valve core and put a dab of rubber cement in the rim that will hopefully catch the nipple.  But I'd like to fish it out if I can.

If you take the rim tape off you should be able to shake it out through one of the holes that you insert the nipples through. I've dropped a few inside rims and never had a problem getting them out this way.


Broken Cogset-Back Wheel will not turn when pedaling I have an older road bike. I noticed that when I tried to go up large hills a few years ago, I would pedal but the back wheel wouldn't get any power. Now the wheel will not turn at all when I am attempting to ride it. When you crank the pedals, te cigarette on the back just spins. What can I do to fix this issue?

Your rear freehub or freewheel is damaged and/or needing service.  The mechanism that engages when you pedal forward, then releases to spin/idle when you are not pedaling or pedaling backwards is broken.  Much of the time these are not serviceable, or are damaged beyond service once they are spinning forward freely.  If you have a freehub, you will most likely need to buy a new rear wheel.  If you have an older style freewheel, it will need to be replaced.