Spring Rate Conversion Chart: Convert lb/in to kg/mm (4k–30k)
Spring Rate Conversion Chart: kg/mm to lb/in (4–30 kg/mm)
Comparing coilover spring rates across brands can get confusing fast—some list rates in lb/in, others in kg/mm. This guide gives you a clear conversion formula and an easy reference chart from 4 kg/mm to 30 kg/mm so you can compare setups quickly.
Quick Tip: Use the chart if you want fast answers. Use the formulas below if you’re converting any spring rate outside the chart range.
How to Convert lb/in to kg/mm
To convert a spring rate from lb/in to kg/mm, divide by 55.997.
kg/mm = lb/in ÷ 55.997
Example: 600 lb/in ÷ 55.997 = 10.71 kg/mm
How to Convert kg/mm to lb/in
To convert a spring rate from kg/mm to lb/in, multiply by 55.997.
lb/in = kg/mm × 55.997
Example: 10 kg/mm × 55.997 = 560 lb/in
Spring Rate Conversion Chart (kg/mm to lb/in) — 4 to 30 kg/mm
This chart covers common coilover spring rates from 4 kg/mm through 30 kg/mm in 1 kg/mm increments. The corresponding lb/in values are rounded to the nearest whole number.
| Spring Rate (kg/mm) | Spring Rate (lb/in) |
|---|---|
| 4 | 224 |
| 5 | 280 |
| 6 | 336 |
| 7 | 392 |
| 8 | 448 |
| 9 | 504 |
| 10 | 560 |
| 11 | 616 |
| 12 | 672 |
| 13 | 728 |
| 14 | 784 |
| 15 | 840 |
| 16 | 896 |
| 17 | 952 |
| 18 | 1008 |
| 19 | 1064 |
| 20 | 1120 |
| 21 | 1176 |
| 22 | 1232 |
| 23 | 1288 |
| 24 | 1344 |
| 25 | 1400 |
| 26 | 1456 |
| 27 | 1512 |
| 28 | 1568 |
| 29 | 1624 |
| 30 | 1680 |
Values calculated using lb/in = kg/mm × 55.997 and rounded to the nearest whole lb/in for quick reference.
Why Spring Rate Units Matter
Spring rates are commonly shown in different units depending on region and manufacturer. Many US listings use lb/in, while many international motorsport spring catalogs use kg/mm. Converting accurately helps you compare coilover options, plan front-to-rear balance, and communicate clearly when ordering springs or discussing setup changes.
