Trying to narrow down an annoyance. Once every pedal rotation there is quite a loud clanking noise, BUT only when in the small ring (compact 50-34). Louder the heavier the load.
It's a BBright pressfit bottom bracket (Cervelo S2) with Sram Force 22 crankset. As it's synced to the pedal rotation I assume that it's the bottom bracket bearings or the crankset, but can't understand why it only happens in the small ring (irrespective of load on either ring).
Nothing as simple as components hitting each other unfortunately
Any suggestions much appreciated.
Clank every pedal rotation?
Re: Clank every pedal rotation?
There's a useful recent thread: viewtopic.php?f=5&t=146300
One of the major themes is that there are many places from where it could be coming...
Can you reproduce it with the bike on a stand?
Jonathan
One of the major themes is that there are many places from where it could be coming...
Can you reproduce it with the bike on a stand?
Jonathan
Re: Clank every pedal rotation?
If only on the small ring, might only "clank" due to pushing harder(?) ....
.... or the protruding end of the gear cable catches on the RH crank (or LH crank if a top swing F mech).
Previous "BB/chainset" noises have included laces knocking on toe clips, jacket draw string draw cord ends dangling on top tube, so quite a few options to investigate!
.... or the protruding end of the gear cable catches on the RH crank (or LH crank if a top swing F mech).
Previous "BB/chainset" noises have included laces knocking on toe clips, jacket draw string draw cord ends dangling on top tube, so quite a few options to investigate!
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Re: Clank every pedal rotation?
Does it make the clank in small ring regardless of which sprocket you're on at the back? Can you make it clank at a different point in the rotation? Say for example if it's in the right crank power stroke can you ease off of the right and push harder on the left crank stroke to make the clank? Check for damaged teeth on small ring, chainring bolts for small ring amongst other stuff.
Last edited by gregoryoftours on 15 Jun 2021, 9:02pm, edited 2 times in total.
Re: Clank every pedal rotation?
No, as I say I've ruled out all types of "stuff hitting other stuff"-type noises. Whatever it is it's not visible.PT1029 wrote: ↑15 Jun 2021, 7:53pm If only on the small ring, might only "clank" due to pushing harder(?) ....
.... or the protruding end of the gear cable catches on the RH crank (or LH crank if a top swing F mech).
Previous "BB/chainset" noises have included laces knocking on toe clips, jacket draw string draw cord ends dangling on top tube, so quite a few options to investigate!
Re: Clank every pedal rotation?
Yes - all cassette cogs on the small ring, although I tend to push harder on the lower rings (bigger cogs) so that may have some bearing.gregoryoftours wrote: ↑15 Jun 2021, 8:56pm Does it make the clank in small ring regardless of which sprocket you're on at the back? Check for damaged teeth on small ring, chainring bolts for small ring amongst other stuff.
I've taken the crankset off, cleaned and greased everything and tightened the chainring bolts. Will test tomorrow.
Re: Clank every pedal rotation?
Yeah, I was about to suggest the chainring bolts. I had a creak in my drivetrain that I thought was either pedals or bottom bracket, but in fact it turned out to be that the chainring bolts had come slightly loose.