Leaf Spring Suspension Q
 

This isn't exactly Stock or SS related, but thought this might be a good place to inquire since S/St is all chassis/backhalf cars these days.

In talking to Viking about a shock package with split mono's and caltracs, the advisor mentioned something that might be useful in my case. He said that instead of running a 250# split mono as per my application, I could run a 175 or 200# split mono leaf with 85 or 100 pound coil-overs. It would provide a little more adjustment (I'm at 2240/1700 pounds) and zero extra fabrication. I already have 18" 250# landrum coils in the front pockets.

Is there any concrete data supporting the added cost of running a 4-spring system instead of a 2-spring system? I don't see where it would be illegal in any rules anywhere, but I've never really heard of such a setup.

Re: Leaf Spring Suspension Q
 

I believe the purpose of the rear spring is to hold the car up. Reason I say this. I broke a rear segment of a leaf spring and Travis Miller at fuel check was kind enough to ask the question of what is hanging down. The car just ran 10.0 something @ 129 something and I could not detect any difference in the run. All I knew is it had to be fixed before we ran class the next day at the Sports Nationals. We fixed it that night and it ran very well the next day.

I think the leaf spring will do the job without any help.

Re: Leaf Spring Suspension Q
 

Leaf spring rate is no different than coil spring rate, yes it holds the car up, but it also regulates the dynamics. The idea as pitched by the Viking tech was that in my case of unfavorable weight and distribution, I would be able to adjust the rear spring from 200 to 350-ish pounds of effective spring rate, whereas with a leaf, I'm locked in wether it works or not. That could come into play since i'm building the truck for S/St, 6.50/6.60/7.00/7.50/8.00 index, and various other classes.

Re: Leaf Spring Suspension Q
 

Typically there are a number of coil spring options that will hold the car up at the desired shock C-C, depending on how much the spring is compressed. A heavy rate spring will require a little and not store a lot of energy. A light spring will need to be compressed substantially more and will have more stored energy that can be used to help get the rear out and the tire applied if needed. It - along with a good shock to control the housing - will give you another tuning tool. I've personally never tried it on anything.

Re: Leaf Spring Suspension Q
 

x2. You want the lightest spring rate that will hold the car up, and let the shock "regulate the dynamics" as you say.