Drivetrain Problem

[martinireland]

Hello People

I am having a problem with a grinding noise from the drivetrain. i have replaced the bb and a new chain put on a different derailleur but its still there. it is driving me mad as i cannot figure it out. have you any ideas of what it could be ?

 

[martinireland]

i have tried a different chainset and still the same, im out of ideas at this stage.

 

[rb58]

Pedal spindle bearings?

 

[guitarpete247]

Is it your knees?

 

[guitarpete247]

How about (serious now) seat stem creaking.

 

[smokeysmoo]

Lots of things to try HERE

 

[RWright]

On my Synapse there is a small metallic stick on chain stay protector at the seat tube end. My chain had come off and hit it and bent it just little. It would make a very slight grinding noise but only in certain gears, it took me hours to figure it out. If you haven't yet, turn the bike upside down and get a flashlight and check around the chain, all the way around, then do the same thing with the bike right side up. Just a couple of ideas. Good luck.

 

[martinireland]

brought bike back to lbs, the bb fitted was a little short so got a longer one fitted this morning. the chainset was rubbing the bb and that's where the noise was coming from........hope its gone now. spent hrs yesterday changing stuff, chainsets,derailleurs, chains all to no avail. I hope to have nothing only a nice mecnanical whirr next spin I go on !