I'm looking into buying a set of D2 coilovers for my EJ coupe and I've come across a set here on HT for a good price, but the guy custom ordered spring rates for them and got a higher rate (12k) on the rear than on the front (10k). My question is, can I switch these springs between front and back to make the front a 12k and the rear a 10k or are the springs not the same between front and rear? I've heard that most of the time, with a coilover setup, the progressive rate springs are ditched in favor of a constant rate spring, so I thought that maybe they were interchangeable.

 

Progressive and linear spring rates are not what make the springs non-interchangeable. Its usually the valving of the dampers, which are specific to a certain spring rate or range. Stiffer front springs is the more common setup.

 

Right, so these are valved for 10k in the front and 12k in the rear. If I swapped them, would it make that big of a difference? They made not be revalved in the front. I remember reading that they only do that if the custom rate is far from the normal rate, which is 11k in the front. The only ones I would worry about are the rears because they are valved for 12k and would have 10k springs on them.

 

You know to be honest, I'm not sure how theirs works. I'm pretty sure that the rule of thumb is 2kg/mm of difference requires a change in valving (so a damper should be able to handle springs within 2k of its original valving), but I'm not sure how it will apply to the adjustable damping. Theoretically, if the range is large enough, you can find a rebound setting to suit any number of spring rates.