Originally Posted by
JohnDThompson
More teeth in the front and/or fewer teeth in the rear will give you a higher gear. Rear cogs are generally less expensive than front chainrings. Make small changes, especially if you're changing the rear cog: a one tooth change in the back makes more of a difference than a one tooth change in the front.
Bigger in front and/or smaller in the rear will be harder to pedal but, if you can turn the cranks, you'll go faster.