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Spring Height, Rate, Deflection & Load Formulae

Question:

Do you have a list of useful equations for performing spring calculations?

Answer:

Yes, we do! Below you will find various formulae that racers have used to evaluate performance of different configuration options. You may also find our online Spring Rate Calculator helpful.

Solid Height

Solid Height
= (Number of
Coils – 0.25) x
Wire Diameter
For example, for a spring with 14 coils and a wire diameter of 0.5”, the Solid Height would be calculated as follows:
Solid Height
= (14 – 0.25) x 0.5
= 6.875

Rate

Rate
= Load (lbs.) ÷
Spring
Deflection (in.)
 

For example, if a spring deflects by 2.75” under a load of 300 lbs, the Rate would be calculated as follows:
Rate
= 300 ÷ 2.75
= 109

Deflection

Deflection
= Load (lbs) ÷ Rate
For example, a spring under a load of 300 lbs with a 109 Rate, the deflection would be calculated as follows:
Deflection
= 300 ÷ 109
= 2.75

Load

Load
= Deflection x Rate
For example, a spring with a 109 Rate and a 2.75” deflection, the load would be calculated as follows:
Deflection
= 2.75 ÷ 109
= 300

Combined Spring Rate

This is used when two springs are stacked on top of each other.

Combined Spring Rate =
(Spring Rate ‘A’ x Spring rate ‘B’)
÷ (Spring Rate ‘A’+Spring Rate ‘B’)
For example if the rate for spring ‘A’ is 200 and the rate for spring ‘B’ is 500, the combined rate is calculated as follows:

Combined Spring Rate =
(200×500) ÷ (200+500) = 143

2016-12-15T14:45:52+00:00 December 8th, 2011|Tech Tips|