Bicycle Mechanics - Can I inspect for a worn cassette?

I have a two year old Shimano 105 5603 triple drivetrain on my bike. This drivetrain now has about 8000 miles on it. I’ll soon be replacing, for the second time, the chain. I was going to replace the cassette at the same time; I don’t want to shorten the life a new chain by installing it on worn cogs.

However the cassette looks like new. The bike also shifts well and I don’t have any problems with the drivetrain.

Does a cassette show wear? Should I change it anyway, based on 8000 miles of use?

Barrettscv: It's hard to judge the condition of a cassette by eye unless it is really trashed. Easiest thing is to go ahead and change the chain, if the new chain skips you need a new cassette, if not you are good. If you don't let the chain get too worn before replacement you should be able to go through several chains before a cassette needs changing as well.

+1,

The best indicator of cassette condition is whether the new chain runs smoothly. the condition of the chain you removed is also a good predictor of a worn cassette, but no assurance of a good cassette.

There's some debate as to whether running a new chain on a worn, but OK cassette is bad for the chain, so what follows is only a qualified opinion based on both my experience and empiracal analysis. Others will disagree.

IMO while chains wear cassettes, the opposite isn't true, and the life of a new chain is relatively unaffected by the cassette it's running on (providing it runs smoothly without skipping). I can usually run 3-5 chains on a single cassette and the life of the last is virtually identical the that of the first.

Thanks, Good to know that a cassette can outlast a chain by more than a factor of two. I'll change a chain every 3000-4000 miles even if it is performing well. I also wipe down the chain, cogs and chainrings twice a month to keep the drivetrain clean. I'll lube once a month and keep the chain well oiled.

Thanks, Good to know that a cassette can outlast a chain by more than a factor of two. I'll change a chain every 3000-4000 miles even if it is performing well. I also wipe down the chain, cogs and chainrings twice a month to keep the drivetrain clean. I'll lube once a month and keep the chain well oiled.

Don't go by mileage, there are too many variables. Measure the chain periodically using a 12" ruler and replace it when it "stretches" or wears so that 24 links or what should measure 12" measures more than 12-1/16". Put a bit of tension on the chain to pull out any slack so you don't get a falsely low measurement.

When I suspect the cassette is near the end (by sound and eye) I run the last chain until they both die. Often this can be well past 1% stretch so I'm milking lots of bonus miles knowing I'm replacing everything anyway.

The last cassette I retired (a 5600 10sp, too) had 12,500 miles on it over the course of five chains. Out of curiosity, I put a nearly new (< 100 mile) chain on it and rode it around the neighborhood, including standing on a local hill. No issues. However I disassembled the cassette and matched each cog against those of a new cassette. This showed the amount of cog wear to be quite noticeable. But after so many miles, I missed the feel of a new chain and cassette on that bike, so on went the new cassette. I don't doubt that I could have gotten another chain and maybe 15k off that cassette.

The last cassette I retired (a 5600 10sp, too) had 12,500 miles on it over the course of five chains. Out of curiosity, I put a nearly new (< 100 mile) chain on it and rode it around the neighborhood, including standing on a local hill. No issues. However I disassembled the cassette and matched each cog against those of a new cassette. This showed the amount of cog wear to be quite noticeable. But after so many miles, I missed the feel of a new chain and cassette on that bike, so on went the new cassette. I don't doubt that I could have gotten another chain and maybe 15k off that cassette.


Let me see if I understand you correctly: even though there is no shifting issues, using the old cassette did have a noticeable (feeling) effect, right? If so, what was it that you were feeling? I'm just curious.

Can I inspect for a worn cassette?

No, it'll change quantum states on you :D

As the others said, it's not something to judge by eye, except in over-the-top cases. A particular customer comes to mind, he seems to ride in one specific cog practically all the time and the wear is so outrageous that it actually is obvious. But he's an exception.

http://draco.nac.uci.edu/rbfaq/FAQ/8d.2.html