I need some help in calculating wheel rates. Im trying to determine what wheel rates I need to correct a design problem with my car. Its a LeGrand Mk18 but has had the suspense pickup points modified and the wheel based extended to 87 inches. I believe the rear end wheel rates are not happy with the front wheel rates. I know the rear inner lower chassis pivot point to the rear lower ball joint length (A = 11.1875), the rear lower inner pivot to rear lower shock/spring attachment point (B = 9.75), the included angle of the rear shock/spring relative to the vertical plane of the upright (C = 15 degrees), and the current spring rate (D = 325 lbs). The front inner lower chassis pivot point to the front lower ball joint length (A = 10.5), the front lower inner pivot to front lower shock/spring attachment point (B = 7.5), the included angle of the front shock/spring relative to the vertical plane of the upright (C = 40 degrees), and the current spring rate (D = 300 lbs). Could some of you math types provide a formula to make this calculation? Specifically, do I need to include the spring/shock angle and if so does it need to be squared? Ive Goggled some formulas and some include it and some square it, is there a consensus? Currently I dont know the instant center or the swing arm length or if these numbers are used by most in calculating the wheel rates. Thanks.
Ted
Ted

















