Cassette life span??

Depends.....

If you clean it and your chain regularly, keep the chain well oiled and replace it before you get 1% elongation, it should last about 3 chains. So maybe 4000 miles or so?

Basically the whole drive train wears together, if you let the chain get to worn then the cassette will also get very worn and when you put a new chain on it will either slip or wear very quickly to match the cassette.

Personally I buy a cassette, chainset and 3 chains (with quick links) at the same time from crc, swap the chain over on a Monday lunch break and just keep on going until the chains break or they start to slip. Then I replace the whole lot and start again. Chains easy to clean and lube well when off the bike.

kettrinboy wrote:

using three chains is a popular method of getting good wear from a chain set but then again if you clean the cassette and chain regularly you might get 6-8000 miles on one chain and then you could replace the whole chainset when the chain eventually wears out, thats what i,m doing on my bikes

+1

My Focus is still on its original drive chain and components after 2 and a half years and about 8000 miles. Everything is very worn but working and hopefully will see me out another season. It will cost be about £200 to replace the whole lot which isn't bad given it will have had about 3 years of wear.