Originally Posted by
cyclist2000
I can see the $185 price with the chain and cog. But did these really need replacing after 4000 miles? maybe the chain but the cassette?
Cassette often needs replacing when the chain is worn... if the chain is worn beyond a certain point and still working on the cogs, a new chain will almost certainly skip under load used with same cassette.
4000 miles is not a lot, but without proper regular maintenance a drivetrain can be worn out in less.