Tein Basic spring rate confusion

[dustinhurley]

On their web page, Tein lists spring rates as front: 336 and rear: 448. Also written as 6/8. If it were 6 x mm for the front spring rate, then they would be calculating that using 56mm. And the rear would be calculated using 56mm as well. 56mm equals 2.2". So, if you calculate the 6/8 spring rate using the recommended ride height of 46mm (1.8"), then you get a spring rate of front: 276 and rear: 368. The Teins go down to -2.7" in the front and -3.8" in the rear.

My question is, which spring rate is the one to use for comparison to other spring rates on the market? Am I confused about the 6/8 thing? Why did Tein use 56 mm (2.2") as their mm height for the calculation?

[dustinhurley]

I got this reply from Tein:

Dustin,

You are calculating the spring rates wrong. The way you calculate the spring rates it you multiply 55.9 times the kg/mm and that equals the lbs/in spring rate. So in the case with the 6kgf/mm front spring and 8kgf/mm rear spring you would do the calculation like this:

Front
55.9 x 6kgf/mm = 335.40 lbs/in

Rear
55.9 x 8kgf/mm = 447.20 lbs/in

Also, we DO NOT use a progressive spring rate for all our coilovers, so you do not have to include the ride height in the calculation. The reason why we do not use a progressive spring rate on our coilover is because we wanted to achieve a constant spring rate no matter what the ride height is set to and that is why we use a linear spring rate. Furthermore, the reason why we offer the same spring rates for our coilover kit is because you can adjust the ride height to compensate for the weight of the car. However, for our lowering spring (Tein S.Tech and H.Tech) we do change the spring rate to compensate for the change in weight (depending on how drastic the weight change is). We have not finished the R&D testing for the EP3 yet and we do not suggest that you install the EM2 springs on your EP3. If you have anymore questions please feel free to contact us. Thank you for your interest in Tein High Performance Suspension.

Best regards,
Sales