My rear derailleur grinds against my cassette. Any Ideas?

Question

Just recently bought a new rear cassette (SRAM 8 speed)

and now my derailleur rubs against it. Is there a quick way to alleviate this or should I just bring it in for a tune-up.

Answer 1

Hey Shane,

Like Mirage said, your cassette may be too big for your derailleur.  Most derailleurs come in a short, medium and long cage design.  You might need a long cage to clear the largest (Low) gear.  Also check your rear derailleur hanger, it might be bent inward causing the derailleur to rub or like said before your chain might be too short when shifted to the lower gears.  Good luck.

Kimber

Answer 2

The B s***w on the derailleur will adjust the jocky wheel cage away from the cogs. This is what you need to do.

Answer 3

As the other answere mentioned adjust the s***w just behind the dropout. That will set the gap especially regarding clearance to the biggest cogs. The other thing you might check is chain length. I've seen a too long chain rub on the smallest cog.

Answer 4

There could be a couple of things going on here...

If you purchased a larger cassette than the original the derailleur may not have sufficient throw to avoid it. Most times when going over a 26T or 28T cog you also have to change the derailleur.

Chain length is another thing. Check to make sure it is correct.

In all, your idea of taking it to a shop is probably best. A good mechanic can diagnose this in seconds.