Caad08

I installed a new cassette on my bike and its making a noise, but only when you're pedaling and putting some power into the pedal. Its like a deep grinding/vibrating noise. I inspected and nothing is really grinding or hitting other stuff, Pullys are clear and and so is the Front derailleur. Also, it is making this noise in mostly in the 52t and 11 & 12 rings.

Everything else is in good shape including the chain, crank, and BB.

Any ideas? Probably will end up bringing it to my LBS.

Velocivixen

Is the cassette you installed the same general sprocket size? Wonder if the guide pulley is rubbing on the bottom edge of the cogs? I'm definitely no expert but just a thought you could check.

Retro Grouch 

That was my first thought too.

My second thought has to do with the chain. Did the OP install a fresh chain to go with his new cassette? A worn chain on a new cassette might do that.

Shimagnolo

Another possibility is the classic ran-the-chain-on-the-wrong-side-of-the-little-tab-in-the-RD-cage trick.

Velocivixen

I just installed a new cassette & nice quality chain last week as well as a new (to me) rear derailleur and I notice slight noise despite everything being carefully adjusted. I'm just giving it time for chain & cogs to "mesh" together. But if you're having loud obvious noise then sounds like something's amiss.

Caad08

The old cassette was sram 12-25. The new one is ultegra 11-23. I looked again and there's plenty of cleareance between the pullys and the cogs. after testing it again its most noticeable when I'm in the 52t and 11t / 12t

Its not a fresh chain but not exactly old. According to the chain wear indicator tool I have the chain doesnt need to be replaced.

Shimagnolo

Was the same chain previously used with this crankset?
A sign of a worn chainring is a loud noise caused by a new chain being tugged off the bottom of the chainring because the teeth have become slightly hooked and are trying to stick to the chainring. (aka "chain suck"). In an extreme case, the chain sticks and gets rammed up into the underside of the FD.

Retro Grouch 

I've seen that done. I've also done that scene.

Al1943

Did you use the special locking made to run with an 11 cog? Your old locking won't work with the 11.

Shimagnolo

Yes, first time I saw it was when I did it.
It took me about a block to figure out WTH I did.

Caad08

I used the one that came in the box with the cassette. Maybe I didn't tighten it enough?

Luckily I got it right this time

I dont think so since the noise is mostly coming from the back of the bike. Like the other poster said maybe I just have to give it time for the chain and new cassette to 'mesh together.' I dont want to risk damaging anything though.

Velocivixen

I'm sure you've probably already done this, and I only mention it because I just put on a different derailleur today, but did you do all the indexing adjustments correctly? I find that on some cogs the chain sounds great and others it sounds noisy, so I make slight adjustments with barrel adjuster until it's all fine. Just a thought. Let us know how it works out though.

jeepseahawk

I forgot to add the spacer last week, rattled like you described. The cassette lock ring went on nice and tight but actual cassette was loose without the very thin spacer. Just a thought, also depends on hub if the spacer is needed with Shimano cassettes.

Wanderer

Very easy to do by accident................