Bicycle Mechanics - Cassette size

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mitok
07-27-04, 08:24 PM
I have a Specilized Mountain Bike. Are all cassette sizes the same or I would need to find out what size fits my bike before getting one. I know the size of the sprokets can be different from smallest to largest but i'm not sure if they vary in diameter on the inside. Thanks

demoncyclist
07-27-04, 08:33 PM
All you need to know is the range of the number of teeth and how many sprockets are on the cassette. You are certain that it is a cassette and not an older style freewheel?
mitok
07-27-04, 08:37 PM
All you need to know is the range of the number of teeth and how many sprockets are on the cassette. You are certain that it is a cassette and not an older style freewheel?

Not to sure what a freewheel is but it's a 5 year old bike wich came with sram 5.0 components so I'm pritty sure that it is a cassette. Thanks for the reply.

Raiyn
07-28-04, 12:46 AM
i'm not sure if they vary in diameter on the inside. Thanks
No the inner diameter of Shimano compatible cassettes (SRAM included) are the same. The only thing you need to concern yourself with is the number of cogs and the gear range.
Michel Gagnon
07-28-04, 08:12 PM
There are two items to consider:

- Width: 7-speed cassettes are narrower than 8/9 speed cassettes.
IOW, if you have a 7-speed cassette, you can only replace it with a 7-speed cassette.
If you have an 8 or 9 speed cassette, than you can replace it with an 8, 9 or even 10 speed cassette. But if you move from 8 to 9, you'll need a narrower chain and a 9-speed shifter.

- 11-tooth small cog?
If your current cassette starts with a 12, it's possible that your hub can't use one that starts with an 11. Details and good pictures at http;//sheldonbrown.com/k7.html