In the modern age, coil springs are being used in ways that were never before imagined. This is why it has become increasingly critical to know the exact spring rate that you are installing. To complicate matters further, the way a spring is installed will vary the way a car ‘feels’. So what should you consider?
When installing a coil spring in a race car, the first thing you should consider is the rate of each spring that is being used. This needs to be done by testing each spring. Especially considering the range that they will be working within and the corner it will be working with. For example, if a 200 lb/in rated spring is being used, the rate will differ when
For example, if a 200 lb/in rated spring is being used, the rate will differ according to the installed to which corner of the car it is being installed in. This is because each corner has a different range of motion. This is why each spring needs to be tested.
A ten step process can be undertaken, this needs to be done after the spring travel and the installed height are determined.
- Make sure you have written down the installed height and maximum compression for each spring.
- Concentrate on one spring at a time, install it into the spring rater and decide which corner you will use each spring for.
- Compress the spring to the normal ride height length.
- Now compress the spring in increments of half an inch.
- After relaxing the spring, re-measure all of the loads. You should end up with two sets of numbers that are identical.
- Subtract each set of increments to find the gain in load versus distance.
- Now it is time to subtract the final load reading at maximum travel from the load at normal ride height and divide by the maximum travel to get the average spring rate in pounds per inch.
- Next repeat steps three – seven for another corner of the car.
- Rate all of your springs
- Make sure you take note of which corner a spring was used on and the rates per corner. This will make it easy if you decide to make a spring change.