How know chainrings worn versus cassette?

[donrhummy]

Just changed my chain and now I'm getting skipping on certain gearing so i know something's worn out but how do I tell if it's the cassette that needs replacing or the chainring?

Also, how long (miles) can you ride with the new chain on this bad setup (avoiding the gears that skip) before that new chain is also stretched/ruined (or will ruin the new stuff)? (I don't know how soon I can get the new cassette/chainrings but I don't want to stop riding)

Info on situation:

1. About 7,000. on drivetrain AND on chain
2. Problem (skipping) started after chain replacement
3. LBS switched my Shimano HG-73 to a SRAM chain. Both 9-speed.
4. Never changed the cassette before. Changed rear wheel 1K miles before.

 

[SEAcarlessTTLE]

My guess is that both are worn, based on what you've said, but you could start by just taking a close look at the teeth. Photos and info on these pages might help, too:

http://www.sheldonbrown.com/chains.html
http://www.camcycle.org.uk/newsletters/36/article15.html

I would expect you use some gears on your cassette more than others, so you can compare the tooth shape across gears and with photos of brand new cassettes to gauge wear, too. Likewise, I'd guess most folks don't wear both or all three chainrings equally, so you probably have some points of reference right there on your bike. (Luckily, you can replace chainrings independently on most cranksets.)

 

[donrhummy]

My guess is that both are worn, based on what you've said, but you could start by just taking a close look at the teeth. Photos and info on these pages might help, too:

http://www.sheldonbrown.com/chains.html
http://www.camcycle.org.uk/newsletters/36/article15.html

I would expect you use some gears on your cassette more than others, so you can compare the tooth shape across gears and with photos of brand new cassettes to gauge wear, too. Likewise, I'd guess most folks don't wear both or all three chainrings equally, so you probably have some points of reference right there on your bike. (Luckily, you can replace chainrings independently on most cranksets.)

Thanks for the response!

Any idea if riding on the new chain for a bit will stretch it?

 

[sogood]

7000miles? If you never changed the chain during that period, then it's likely both the chain and the cassette are past their use by date. If you had been taking good care with chain change at the appropriate time points, then typically one needs to change the cassette with every two chain changes.

At 7000miles, the chainring is unlikely to be an issue.

Yes, change your cassette ASAP or you'll continue to experience skips and accelerate the wear on your new chain.