Spring Rate Conversion Chart and Spring Info

Coilover Spring Rate

One of our specialties is offering custom spring rate options on our coilovers. We often see requests for spring rates in both KG/mm and LB/in. All of our springs will be based off the KG/mm scaling, so we put together a handy chart here to help you convert over your spring rates from the standard scaling. 

Springs are rated in kilograms per millimeter (KG/mm) or pounds per inch (lb/in), which represents the amount of force required to compress the spring 1 MM at its fully extended length. A spring rated at 12 KG/mm will compress 1 MM for every 12 KG of force exerted on the spring. Compressing the spring 2 MM would take 24 KG pounds of force with a linear spring. Conversely on the LB/in scale, it is the amount of force required to compress the spring 1 inch at it's fully extended length. 

For reference, 1 KG/mm is roughly equal to 56 LBS/in.

LB/in to KG/mm:

700 lb/in = 12.5 kg/mm
650 lb/in = 11.6 kg/mm
600 lb/in = 10.7 kg/mm
550 lb/in = 9.8 kg/mm
500 lb/in = 8.9 kg/mm
450 lb/in = 8 kg/mm
400 lb/in = 7.1 kg/mm
350 lb/in = 6.2 kg/mm
300 lb/in = 5.3 kg/mm
250 lb/in = 4.5 kg/mm

KG/mm to LB/in:

16 kg/mm = 896 lb/in 
15 kg/mm = 840 lb/in 
14 kg/mm = 784 lb/in
13 kg/mm = 728 lb/in
12 kg/mm = 672 lb/in
11 kg/mm = 616 lb/in
10 kg/mm = 560 lb/in
9.0 kg/mm = 504 lb/in
8.5 kg/mm = 476 lb/in
8.0 kg/mm = 448 lb/in
7.5 kg/mm = 420 lb/in
7.0 kg/mm = 392 lb/in
6.5 kg/mm = 364 lb/in
6.0 kg/mm = 336 lb/in
5.5 kg/mm = 308 lb/in
5.0 kg/mm = 280 lb/in
4.5 kg/mm = 252 lb/in
4.0 kg/mm = 224 lb/in
3.0 kg/mm = 168 lb/in
2.0 kg/mm = 112 lb/in
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