Greiselman

I just installed a new Shimano chain and cassette on my bike and I'm getting some chain noise... but only in the three smallest cogs on the cassette, in both the big and small chainring. There's no skipping per se... just a constant grinding. Thoughts on what the cause might be? (Searching reveals lots of "you need to replace the cassette and the chain at the same time" responses, which obviously isn't the issue here.)

Thanks!

bikemike73 

Did you replace it with the same size cassette and chain ?

I JUST had a similar issue. ( new cassette and new chain )
But I increased the size of my cassette to 12-28 from 13-23

Making the chain shorter by one more link helped resolve the issue 90%.

Still need to " fine tune" the RD though.

There are people on this forum that are much more knowledgeable than me. They helped me........................ and without their expertise and time, I would still be trying to figure it out.

I cannot THANK them enough....they are the BEST !!!!

I'm sure they will respond and have more detailed answers than I provided

Some pictures might help

Greiselman

Yep - same cassette/size, same chain cut down to the same number of links. Figured I might need to tweak the RD - wanted to check here first.

Moisture

Did you try playing around with the barrel adjustor and limit screws?

cxwrench

Just stop. You don't just randomly tell someone to 'play around w/ the barrel adjuster and limit screws'...that is terrible advice.


New chain and cassette, old chainrings? Now you know where your problem is. Slightly/somewhat worn rings are trying to hang onto the chain as it leaves the ring(s).

alcjphil

This would be my thought as well. How much use have the chainrings seen?

Greiselman

Coming up on 5000 miles. I've been good about maintaining the drivetrain so I was hoping to avoid replacing the chainring so soon... may just run it by my local shop to have them take a peek.

dsbrantjr

You may need to slightly readjust the indexing (wrongly called "tension") or less likely limits due to the change in cassette. Even same model cassettes may have slight manufacturing differences. But make the adjustments purposefully, not "playing" with them. Here is a good procedure: https://www.parktool.com/blog/repair...eur-adjustment Follow the steps in order, you should have to make only minor adjustments.

mack_turtle

this is just plain irresponsible. please stop posting ignorant nonsense before someone follows your advice and damages their bike.

mack_turtle

drivetrains are relatively complex with a lot of moving parts and parts that wear out. without seeing it in person, I can't narrow down what among the two dozen possible issues is causing this.

one theory to consider: which cassette cogs do you use the most? smaller rings generally wear out faster because the same amount of force can be placed on fewer teeth when used, so there's more force per tooth on that cog. it's possible that if you used your smaller cogs more than the others, those wore out before the others. for most cassettes, that means you have to replace the whole cassette. that's just one theory.

alcjphil

Read the first post. OP changed the cassette as well as the chain

Greiselman

truthfully I think I spread the love across all of the cogs... but should that matter, as I've replaced the full cassette?

I'm going to follow dsbrantjr;'s guidance and will report back with pictures if I'm still having an issues. And, most importantly... no, I never planned on "playing around" with any RD adjustments.

mack_turtle

derp. I missed that somehow. apologies.

what about the derailer hanger alignment? there's no reliable way to eyeball that, as a misalignment can be in more than one axis and might be just enough to throw it off but impossible to see. use a hanger alignment tool to make certain.

Iride01 

When do you notice this noise in the smaller rear cogs? If it's while you are riding a putting out a fair amount of power at speed, then it might just be the way the rollers have to engage the smaller sprockets. I notice this more with freshly cleaned cassettes at times I'm doing a fast ride in peaceful conditions on a smooth surface. I feel it more than I hear it. Don't know that I've ever noticed it when the bike is on a stand just running through the gears.

edit....
Were the spacers between some of the cogs that you might have missed or messed up when putting on the new cassette?

Redbullet

It might be hard to believe, but sometimes new parts can be defective from the start. One year ago I bought 2 new SRAM cassettes (11 cogs) and a rear derailleur Force 22, from a reputable bike e-shop. All new, in sealed original package. After one month of desperate attempts to adjust the system, including threads on this forum, I found that one cassette was defective: a few teeth of one cog slightly hooked the chain and one ring was 0.3 mm narrower than the others. The derailleur had a big play at one of the bolts. I sent the cassette and derailleur back to the e-shop, together with explanations and a few pictures, then SRAM replaced both in 2 weeks with no other questions. Then, everything worked ok.

Greiselman

Readjusting the indexing worked well - thanks, all!