Spring length
 

I've got a 400/275 setup on FCM SA (with helper springs), and am not completely thrilled with the setup over rough Boston roads (1-ride is rough, 2-clanging noise (dunno if it's from helper springs or from coils banging together)).

From the brief search it seems if I were to keep my rates, I'd have to go with longer springs (I didn't test for coil bind). 8" in the front and 9" in the rear.

I just found 2 Swift springs 8" x 350lbs. Obviously, that represents a slight drop in spring rate. What 9" spring in the rear should I look for, if the immediate goal is to lose the helper springs? Or can a rough-ish ride be solved by only going much much softer than those rates?

For the record, when I had FM setup (even though I had to raise it with spacers due to lack of ground clearance) the ride was nearly perfect. This was with Gen 2 FM springs, and rates were 318/233.

My ideal ride height would be 12.75" front/13.25" rear.

Thank you in advance!

It sounds like you dont have a high enough spring rate and are bottoming to hard. As someone in the area, 700/400 on high end shocks valved to handle it is mighty comfortable.

Hmm, interesting. Although Worcester roads are a bit smoother than Boston's, would you mind giving me a ride?

I'll drive out, of course.

I havent been driving it much on the street any more and its stored up in NH. How bad could boston's roads be, worcester is so bad my last car had the rear view mirror fall off, then I fixed it with the actual rear view fix kit and it failed a again, 2nd time was the charm on that one.

Boston roads are pretty bad. If you've ever driven down Triboro bridge in NYC, this is what my street reminds me of in its current state.