if you're stepping down, then you may be able to get away by just using your tensioner. If you're maxing on your your tensioner's range, then you'll need to take off a link. Can you give us more info on what bike, tensioner type etc.?[/QUOTE
Trek Marlin SS. I don't have a chain tensioner, it's just built in to the frame with sliding bolts.
Tensioner bolts are currently about halfway back on the 20T and there is some chain slap.
:skep: He'll be just fine with 32x18. Why spend extra on a chainring, lessen clearance, with virtually no benefits?If it were me I would go with bigger ring and keep the 20 tooth cog because the system will run smoother. You could use a 35/20 because it is a very similar ratio to the 32/18. You will need to add some links or slide your wheel forward.