Hello again,

I posted a thread a couple of weeks ago about a mystery squeak coming (seemingly) from my cranks on my Trek Madone 5.2sl I bought used this past summer. After trying a few things suggested on the thread, I most recently brought it into the local Trek dealer and had them completely replace my bottom bracket with a brand new Dura Ace BB. The mechanic has been servicing Treks forever and said my old BB was pretty well worn...should fix the problem. I travel out of town for work, and live in Michigan, so the past few weeks I've been limited to riding on my trainer and not outdoors (can't produce the squeak on the trainer).

Anyway, with some warm weather this weekend I went out for a ride to test out the new BB...as before, the squeak started about 8 miles into the ride and I dare say, it was worse than ever. Another solution (and $$) down the drain.

The other fix I've wanted to try is to switch my rear wheel with another one. So, I put on a different rear wheel borrowed from my dad, took the bike out on the same course, same effort, and there was absolutely no squeak at all. Crazy.

So, this leads me to the next question: What's wrong with my rear wheel, and why does the rhythmic squeaking/rubbing sound come from my cranks and not the rear wheel?

I have Velocity wheels riding on fairly new GP4000s. I did bring my rear wheel in to a bike mechanic previously who tested all the spokes & said there is absolutely nothing wrong with the wheels. Since Velocity is a local company he said that if there was anything wrong with the wheels, Velocity would replace them, but absolutely nothing was wrong.

Any ideas? Am I condemned to buying a new wheelset?

Thanks for any opinions.

Check the following on the wheels:

1. Machine lacing as opposed to all-elbows-out-pulling or all-elbows-in-pulling.
2. Using a tension meter - check to ensure drive side tension is at least 110 kgf - or higher for low spoke count wheels.
3. Place one drop of light weight oil at each spoke crossing point. Give all parallel spoke pairs on both sides a good hard squeeze for two rotations.

...not much I can suggest without more details and having the wheel before me.

It does look as though you've eliminated the frame...

=8-)

I don't know about Velocity wheels but I had some traditional LBS built wheels that had a mystery squeak when new as well. I have Dura Ace 9 speed hubs laced up to DT Swiss RR 1.1 double ferrule rims. Turns out they needed to be "de-stressed" not once but twice. What happened was that the rear spokes had all gone pretty loose for some reason. Now these are 36 spoke wheels, built for durability since I don't race and I was 250#pounds at the time (I'm now at #190). My mechanic stands by his work and he has a good reputation in the area. All he needed was about 15 extra minutes in the truing stand (each time, I did have to take it to him for one final tension and de-stress if memory serves) and he manually squeezed different groupings of spokes together then brought up the spoke tension 1/4 turn all the way around, then checked for side to side and up and down runout. I think a couple of the ferules settled in which was the major issue. I don't know if your rims have ferules or not but they can sometimes be the culprit where they seat down causing loosening. In my case the rear wheel squeaking did appear to be emanating from where the spokes crossed and were loose. Hope this helps.

On most if not all of their rims, Velocity does not use eyelets / ferrules.

=8-)

Given your description, and assuming that swapping out a rear wheel
cured a "squeaking/rubbing sound coming from the cranks", I'd be looking
at the front derailleur cage, the adjustment of it, and anything else that
might be causing a slight chain interference as you exert maximum effort
and flex the crank a little bit so it slightly alters the chainline.

Otherwise, I got nothin'.

When you switched wheels did you also use a different QR skewer? I have found several mystery wheel noises ended up being caused by alloy or other non-traditional skewers. The trainers extra clamping force may help to eliminate the noise. Try a good ol' steel Campy type skewer.

why does the rhythmic squeaking/rubbing sound come from my cranks and not the rear wheel?

The frame can act like an amplifier and make a wheel noise sound like the BB, or the BB sound like headset, etc.

Look for a scuff mark on the tire (probably on the left side).

While squeak, clicks or chirps synchronous with pedaling usually indicate a crank/bb related problem, that isn't always the case. One other thing that changes with pedal motion is chain tension, which rises and drops twice per revolution. So if, for example, you have a broken axle, or loose cones, the wheel will shift to the left whenever chain tension increases. This doesn't show up on stands or trainers because the tension isn't high enough.

Another likely related cause is a broken axle. A broken QR axle is often misdiagnosed as just about everything else, because the QR skewer holds it together making it not obvious even if you remove the wheel. But it allows flex with chain load, and the chirp can come from within the hub as the broken axle deflects and rubs the shell.