From Newsgroup: rec.bicycles.tech
On 8/7/2026 2:41 PM, Mark J cleary wrote:
Today a friend of mind ask he about his road bike. He has a
litespeed Ti of older vintage with 10 spd campy. I had
worked on it previously about 2 years ago because no one at
the 2 LBS could get it to shift exactly correctly. Well I
remember swapping out cable and housing using the metal
ferrules and going through it and it shifted like a dream.
He thinks I am the ace mechanic because I could do what the
LBS mech could not.
He hates to bug me knowing and know I only want to work on
folks bikes I know due to general issues of personal safety
and characters showing up at my door. But now his Litespeed
makes a rubbing metallic noise but only going uphill on a
grade. Does not happen on flats or going downhill. He sort
of hears it under him not it back.
He had a LBS check it out and put it on stand but the
mechanic could not get it to duplicate the issue. So he says
nothing he really can do. He had another person at the coop
look at it and said same sort of reply. So he comes to me
and I start trouble shooting. Does is stop when you don't
pedal? Does the sound seems like it is coming from front on
near cranks? Does changing gears cause it to stop. I kept
asking questions and he said no one had done any of that
with him. Duh?
I told him something was flexing to cause that and it could
be BB bearing going bad, or even a brake rub/tire rub? He
got concerned about the frame flex thinking that was bad
thing. I said no frames will flex and something is flexing.
I have him a list of things to try riding to see if doing
these things made it go away or worse. He is in the process
of doing that and as I explained you have to change only 1
variable at a time or you don't know.
I am waiting for what he might find. My thought is a bad BB
bearing worn, could be a change ring bold but I doubt that,
maybe something in the cassette. It is stop though when not
pedaling.
My point is that all the new technology and AI and the local
mechanics seem to lack ability to diagnose and eliminate. To
me it is practicing medicine on a bike.
I get it nailed nailed down in time.
Congratulations on your technique.
Yes it could be a crank bearing. Slip the chain off the
inside and turn the crank in your fingers. Roughness? Press
inward and repeat. Hold both arms and feel for play.
If still no resolution, stand on the pedals holding the
front brake firmly, right hand on a table or doorway. Press
hard on one pedal, backpedal, repeat with the other pedal.
Crank-to-spindle noises are different for the various crank
formats, so no general rule there.
Could also be a new tire a bit too wide for the frame. Tight
spot is between the chainstays so look there first. Any
paint scuff on inside face the chainstay? If that's true,
normal frame flex will cause the rub.
You may be at a disadvantage without actually test riding
the bike. Noises are difficult enough, but remote diagnosis
or bike stand diagnosis makes sleuthing harder.
--
Andrew Muzi
am@yellowjersey.org
Open every day since 1 April, 1971
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