Hi everyone, I’m new to working on bikes but would appreciate some guidance in adjusting my drivetrain
When backpedaling in the largest cog in the cassette, I’m getting this rumbling noise (I believe it’s coming from the back somewhere). The chain also seems to rub the front derailleur cage in this gear, no matter which front chain ring I’m on. Could both issues be related?
I believe I caused this issue when I was cleaning my chain. I took it off and shook it around in a jar of degreaser, and I think since I put it back on it’s been making these rumbling and rubbing noises. I could be wrong about when it started happening though
I tried to take a video of each part but I’m a little clueless, let me know if I should take photos / videos from a different angle.
Really appreciate any help!
What’s causing this rumbling noise in the largest rear cog?
byu/LarryLotus inbikewrench
by LarryLotus
8 Comments
https://preview.redd.it/9obhj5e0wk3f1.jpeg?width=3024&format=pjpg&auto=webp&s=9dca8c720d8a0b658d759f35e14d1f3655e3bb1a
Here’s a photo of the rear. The person I bought it off had just replaced the derailleur hanger, am I crazy or does it look a little bent?
I wouldn’t worry about what happens when you pedal backwards unless you do that frequently.
This will help reduce front derailleur rub
https://www.parktool.com/en-us/blog/repair-help/front-derailleur-adjustment
It looks like your upper jockey wheel is pretty close to the cassette. Can you increase the B tension a little more?
Tightening the B screw will help open the gap between your derailleur jockey wheel and the larger cogs on tote rear cassette
You need to screw the B screw in a bit, the upper roller is grinding against the largest cog.
B limit is to close the jockey wheel is rubbing the biggest cog
Thanks everyone, just adjusted the b screw and it fixed the rumbling.
Also adjusted the limit screws in the front but without markings it’s difficult for me to tell what’s going on, but the chain isn’t touching the front derailleur now so that’s great
Going for a ride now, cheers!
Turn the “B” limit clockwise. This will pull the derailleur away from the largest cog.
That is what it is for.