F5000 spring rates

[tige00]

What spring rates do people run on their f5000 cars, specifically the rear.

[jimclark]

What spring rates do people run on their f5000 cars, specifically the rear.

Rather broad question....mucho variables.

[swiftgrant]

Talon MR1a, I typically run 400lb/inch. Have run as low as 350 and as high as 500
the car has rear motion ration of about 2

[tige00]

Thanks for your reply

[S Lathrop]

You need to know what the motion ratio of you suspension system. Next you need to know how much weight a corner is supporting. I start with a spring rate that gives a wheel rate equal to the weight that corner is supporting.

Example, you have a corner that weighs 400 pounds. You could have a motion ratio that is say 2 to 1, one inch of shock movement to 2 inches of wheel movement. The un-sprung weight on the corner is 75 pounds the weight of the wheels, tires uprights, etc. The sprung load would be 325 pounds. For a spring rate of 350 at the wheel you would need a spring of 1400 pounds per inch on the shock. Numbers like this example are for cars running with very low ride heights. If you want to run a 3" ride height, vs a 1.5 ride height, you can a lot lower spring rate. maybe close to half.

The best ride height is determined by analyzing suspension geometry. I pay a lot of attention to the location of the roll centers and pick ride heights based on the roll center locations.

[tige00]

Great info thanks so much