When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
You need to figure out at what rpm your motor puts out the most torque. I would think your cruising rpm should be near that. If your motor is radically hopped up, it will need to rev higher to make power. With those big tires, the higher gears would probably be a good idea.