Rear coil spring rates


Well-Known Member
I decided to go ahead and run a link-style rear suspension on my Toyota. I am going to be running a set of 14-inch King coil-overs on the rear mounted just slightly forward of the half-way point on the lower link bar. I have a single spare tire and an 18-gallon fuel cell mounted behind the rear axle and I am looking for suggestions as to where I should start with the spring rates for the coils. I know that I am going to have to fine tune the rates once the coil-overs are bolted on and the truck is running through the rough stuff, but I would at least like to be close out of the gate. Thanks in advance.

Courtney Halowell
Editor, StreetTrucks Magazine


Well-Known Member
Need just a tad bit more info.
Length of trailing arm???
inches in wheel travel.????
unsprung seight????



Well-Known Member
hit <A target="_blank" HREF=></A> they have a new spring rate calculator that you enter in your figures and it tells you a starting point. Don't know how accurate it is maybe Donahoe or Camburg could enter some real values from their setups and see how close it is to the real world...Curt

VORRA Class 7


Well-Known Member
forward of half way is a little to much of a motion ratio.
at half way the spring rate on the shock must be 4 time the rate that you want at the wheel. for instance if you wanted 100 lb/in at the wheel which is a pretty soft rate, you would need 400lb/in at the shock and with dual rate that puts the two coils in the 700 and 900 lb range.
a 14" 900 lb coil is a marginal design and is prone to coil bind. Eibach's heaviest coil in a 14" 3" ID is only 600lb/in and only has 6.84" of travel. 2 of these coils wont even give you your full 14" of stroke and would only give you 66 lb/in at the wheel if mounted half way.
if you want to bench race on the subject feel free to give me a call at Donahoe Racing 714-632-3033

“Those of you who think you know so much really annoy those of us who do!”


Well-Known Member
how do you determine how much travel a spring can have? is it listed anywhere? thanks

"We are the music makers, and we are the dreamers of the dreams." -- Willy Wonka