I'm in the market to purchase some higher spring rate springs for my new apexi esv coilovers. Im familiar with different spring rates but I see that swift/stance offer springs in different lengths like 150mm, 175mm, and 200mm. What is the difference between these or is it determined by the length of travel needed?

 

Yes, length of total travel before coil bind needed will determine which length you need.

If you want the car lower than the lowest spring perch setting, you need shorter springs. If you want to keep some preload, you'll need to figure out the longest spring that will fit.

If you're happy with the current height and adjustment range available, just buy replacement springs in the same length you currently have. You'll still need to lower the perch slightly to keep the same ride height with stiffer rates though.

 

Will shorter springs mean a sacrifice in ride quality? What other companies make custom rate springs for coilovers?

 

If you go too short, then you will be pretty much riding on your bump stops or bottoming out your shock shaft. Yes most quality spring companies make different spring rates for coilovers it just depends on your inner diameter of the spring. If your planning on changing your rate I would try to contact Apexi to see what those shocks can handle before you end up blowing your shocks.

 

hypercoil, eibach ers, and swift all make custom springs for coilovers. just determine the inner diameter, length of spring, and spring rate you want. search the RR/AX forum for hypercoil or hyperco for some good input on these particular springs.

hypercoil: http://www.hypercoils.com/
eibach: http://performance-suspension.eibach.com/
swift: http://www.swiftsprings.com/