2003 Polaris 3 PRO X Factory Service Manual, Page 215Get this manual
STEERINGFRONT SUSPENSION Dual Rate Springs
During initial compression of dual rate springs (two separate springs stacked on top of each other, both springs will compress resulting in an initial spring rate that is combination of both springs, yet less than either of the individual springsThe chart at right shows the initial combined spring rate using two individual spring ratesThe initial spring rate is based on the formula belowFor example, if you stack 150 lbinspring in combination with 225 lbinspring, the chart will give you an initial spring rate of 90 lbinAs the springs compress, there is point where the small spring compresses to solid, or the spring retainer contacts the transition spacersThis point is called the transition pointAny compression of the springs after this point is reached will result in spring rate equal to the spring rate of the long springThis is true because the smaller spring is no longer being compressedInitial Rate=(Spring Rate #1) (Spring Rate #2) (Spring Rate #1)(Spring Rate #2) Example: (150 lbin) (225 lbin)= (150 lbin)(225 lbin) 33750=90 lbininitial spring rate 375