Bicycle Mechanics - Chain Rub Sounds making me feel stupid

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EliB
12-29-07, 05:22 PM
So here again I am confronted with a slight mechanical malfunction that I know is easily diagnosed and remedied .. but I am not the one to do it! How often I have gone to lbs and with a turn of a screw or some minor ajustment my problem is solved. I walk out (often not having to pay) not feeling grateful but like an idiot!

Thank Gd for the anonymity of the internet!

Problem: when the chain is in the middle of the rear cog I am getting a persistant rubbing sound. This cannot be replicated when there is no weight on the pedals - when I have spun the cranks while off the bike to see what is going on - when I do this there appears to be no contact between the chain and the fd.

I'd be grateful to anyone who would patiently list the assessment process that I should -if not understand at least know by now!

operator
12-29-07, 05:52 PM
It's a chain rub noise? Are you running a double? Triple? Recent sound? Which chainrings/cog combos does it give it in? Do you have a trim function on your shifters? Are you using friction?
EliB
12-29-07, 07:22 PM
It's a chain rub noise? Are you running a double? Triple? Recent sound? Which chainrings/cog combos does it give it in? Do you have a trim function on your shifters? Are you using friction?

left out a lot of info didn't I!

Sounds every bit like chain rub to me. I am running a double. It is a recently noticed sound. It happens on the large front middle rear. I do have a trim function (using it is not helping) and is friction (Campy Chorus fd/Record shifters)

Bikedued
12-29-07, 07:57 PM
On many of my bikes The slightest bit of FD lever can reduce it or make it go away completely? Shift into the gear you want, and depending on which way you moved the rear, move the front lever a bit to the same direction. It's part of the fun of using friction:D.,,,,BD