Crank/BB only swap and you should be fine. stick with the chain that fits your cassette.
If its an 8 stay with the 8 spec.. 9 is internally different. to pack in more cogs in the same space.
only thing that stays the same is the 1/2" distance between the pins & rollers.
measure the chain, 12" of chain should be no more than 1/16th out of spec,
over-length 'stretch'=wear.
Last edited by fietsbob; 02-23-11 at 10:35 AM.