brownsleisureworld.com for full sled diagrams. top has less teeth, bottom has more... ie a gear reduction. most people gear lower for a better hole shot, others gear higher for lower rpm at crusing speed.
If you drop teeth on the top you are gearing it down, which will give you more acceleration for a small reduction in top speed(per tooth), same thing with going up teeth on bottom. Going up teeth on the top will gear you higher for more top end(if you have the power)for a reduction in acceleration.
Also look at gearing charts, only certain sprocket combos can be ran with each pitch of chain. Usually dropping one tooth on top is a good improvement for almost all sleds.
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