Chopping up coils...

I have a set of rusty's 4.5 inch coil springs that im swapping out for a set of rusty's 3 inchers. My mom wants a lift on her XJ now and I was thinking that I could give her a 3" lift by cutting the 4.5 inchers down to size. Her XJ is street only and ride quality takes precedent over everything else.

If Rusy's 4.5" and 3" coils are the same spring rate (non STS), can I cut the 4.5 inchers down to the the same length as the 3" springs and get 3" out of them, or are there some coil spring physics that im missing?

What you're missing is that a coil spring is a torsion bar wrapped into a helix. As you make it shorter, you also make it stiffer. Therefore, if you want both yours and your Mom's at 3" but she is concerned about ride quality, give HER the ones that are made as 3" coils, and cut your 4.5" coils for your XJ.

Go gradually, because it's a lot easier to cut another half coil off if you're too high than it is to add it back if you cut too much. The rate changes, so the results are not entirely predictable.

why ya taking the 4.5" coils off?

Eric

The 4.5 inchers gave too much lift and with 31s its just more than I need. Plus, I want to keep it as low as possible for the CG and CA angles. On the trail i figurel I'll compensate with more armor.

gotcha