Hi, I'm tying to get rid of some of the harshness in the rear of my 68 Chevelle convertible. I have Vari shock coilovers at all 4 corners 12" spring w 5.25" travel. 450 lbs fronts 200 lbs rear. I'm ok with the front of the car it's the rear end that I'd like to soften.

So my question is which spring rate. I'm going with Swift 12" progressive springs, my choice is either 150/400 lbs or 200/500 lbs. About a 3500 lbs car.

Any imput would be great. Thanks, Tony

 

I have a 3,600’ish poud car with 200-300 inch lb progressives on the rear and I dig it. The fronts are 425/530 fwiw.
Maybe go with the softer of the two.

 

So the 150/400 then ?

 

I think so. Especially for a cruiser type car if that’s what you have.

 

Y2K thanks for the input. I went with the 150/400 Swift Springs and they solve the harshness in rear suspension. Manhole covers, small potholes and expansion joints are no longer a traumatic jaw jarring experience. Car does feel a bit bouncier in the rear so I stiffened up the damping in my single stage shocks.We will see !

 

I’m glad they worked out and I hope the float isn’t a deal breaker. It’s hard to build a jack of all trades, master of none but hopefully you’re close. What kind of car are you working on? My car with the progressive springs is a ‘95 Mustang (solid axle) and the progressives rates are fairly close to the OEM springs. They’re stiffer by a little and the drop was less than an inch. The shocks on that one are “only” KYB Excel G’s but they’ve been doing well at controlling things for nearly a decade now.

 

 

Real cool