Cross post from suspension It's a 2007 yz450 and I have been reading a lot of posts looking for some direction on suspension mods. I have also tried some spring weight calculators and now I'm totally confused. My local Yamaha dealer works with Pro Action and they said that based on my characteristics (41 yrs, novice (but improving) 5'10" 205 lbs without gear...that I should be able to use the stock springs (which are apparently .48/5.5) and then have it revalved. Some others here have suggested the same. I'm fine with that because it saves me $200! However I also read that stockers are for guys around 170 pounds and that its a 'must' to respring to .49/5.6 (or possibly even 5.7 on the rear). Based on how the bike compresses when I sit on it I tend to think it needs heavier springs - but I certainly don't think I know more than the pro action guys. Appreciate any feedback to help me make up my mind.