Originally Posted by
Burton
OK so I work as a mechanic myself and can't say some of this makes sense to me. Going from a 32T to a 23T without changing the front crankset would definately require shortening the chain. Going from one cassette to another normally doesn't require resetting limit screws - the derailleur starts and stops at exactly the same points for all 8-speed cassettes regardless of tooth count.
You "size" the chain when cross chained in small/small or big/big ... ( some people even check it in the "big meat". big chainring/smallest cog. Then the der pullies should be in vertical line under the rear axle ) the rear der. should take up the slack. I wouldnt worry abot it, esp if its a long cage.
...as for cass, even know they are supposed to be the same spacing, they are all over the place, some times you need a spacer, some times you dont ... but double checking the limits is never a bad idea.