Spring Rate Calculator

I'm trying to figure out the correct spring rates for my son's KX250F.

I've checked out the Race-Tech spring rate calculator, as well as the on on MX-Tech's website and they both come up with different spring rates. With Race-Tech's calcs, I can stick with the stock rear (5.0) and just throw some softer fork springs in (.42). According to MX-Tech's calculator, I should go with even softer fork springs (.40) and a softer shock spring (4.8).

Does anybody know of another calculator so I could go best 2 of 3, or know if of the two calculators tends to be more accurate?

Thanks for any help.

deano...

My son run's about 145 with gear on and we ride so-cal desert mostly. The soils here cover everything from soft sand, to rocks to hardpack. Mostly need something that can handle the long trails of whoops.

Given that he's growing quickly, I think we'll just stay with the stock shock spring and go with the Race Tech recommended fork springs. While it might run on the slightly stiff side for now, at least he won't be out growing them next week.