MoPar leaf spring rates

[metallicareload99]

I need new springs for my Charger, the XP springs are shot.  I have a 440 with 4-Speed.  I plan to run 1.06" torsion bars upfront with Firm Feel sway bars front and rear for better handling.  Drag cars with manual transmission seem to run higher (stiffer) spring rates than auto cars.  I think I'll avoid the 3,800# super stock springs, but I'm thinking that SS springs designed for the lighter cars might help traction and provide a decent ride due to what I suspect is a lower spring rate in comparison to the 3,800# ones.

I was wondering if anyone knows what the spring rates are for some of the various Leaf Springs out there?  Specifically I am curious as to what the Super Stock spring rates are?  I know they have several versions based on the weight of the car but I can't find what the rates are.  Here are some that I have found:



CALTRACS Split Mono Leaf-220-225#

3,800# SS-?

I have heard that late 60's B-Body Station Wagon springs are around 150-160#

Hotchkis-160#

MoPar XHD-140#?

Mopar Performance Kit Car Springs-120#

[HPP]

SS springs range from 180-200# with the manual trans springs being heavier.

Matching spring rates to torsion bars along with the sway bars can be done in a myriad assortment of ways. The biggest determining factor in what rates you want to acheive is going to be determined by the weight distribution in your car. The more nose weight you have, typically the more t and s bar rate you need up front to support it. However, the end of the car with too much spring rate is going to be the end that slides first when pushed in a turn, so you don't want to get too crazy with rates right out of the box. If your adding a rear sway bar, you actually can go lighter on the leaf spring rates to keep things matched better.

Don't forget you can also get springs from Landrum, Afco, and Speedway in a variety of rates. I'd also suggest deciding on the front end combo you want first, then build the rear to match it. The reason for this is that there are only 3-4 decent handling size t-bars, only 3-4 decent sized sway bars, but you can have a leaf spring built in an almost infinite number of rates.

[Mike DC]

  
Just to throw this out there - XV Motorsports actually decided to run slightly softer rear leaf springs (compared to the factory stock R/Ts) on their level #1 setup.  That's on a package deal that includes big aftermarket sway bars for both ends and front torsion bars stiffer than stock.    
 

[HPP]

Very true.

If you ever have looked in the Oval Track Modification book, they similarly recommend the softer rear rates, typically matched to 1.12 or 1.18 t-bars, and recommend adjusting balance with different sized front sway bars, and no rear sway bars. The oval track springs are a sort of hybrid. The only use four leaves, but the leaves are thicker than stock or SS springs. They also have a shorter front segment, like an SS springs pack, and are available with zero or 1 inch of arch.

My current suspension package is using the oval track springs. I've actually got two potential set ups; 1) .96 t-bars, 1.125 front s-bar, 120# leaf springs. 2) 1.22 t-bars, 1.125 front s-bar, 120# leaf springs, 1" rear under axle s-bar. I haven't test teh two yet to see which one I prefer, but all teh bits and pieces are there to swap out.

[metallicareload99]

I went with new MoPar Performance XHD replacement springs.  It handles better and heels over much less in turns, I wish I did this years ago

Before:


After: