I had the 8.1kg/mm spring on the bike last and it seemed real soft :huh. RaceTech settings: Weigh: 220lbs. Riding Type: Desert / Enduro / Trail Age: Standard Age - Up to 44 Skill Level: Dirt Amateur Height: Tall (6'3" or 190cm plus) Gas Tank: Oversize Gas Tank I tried it saying I weighted 300lbs and wanted to do supercross and RaceTech recommendation still didn't get close to an 8.1 spring. So what's the deal? Well, someone had adjusted the stock shim stacks to be really light. I noticed my stacks were different from jcalis, his being stock. According to the Shim ReStackor's spring selection page, I should be able to make any of my springs work. I'm going with the 8.1 in case I want to haul some gear.