Rear Coilover Spring Rate Help
 

Looking for advice on what spring rate would be best and why?

Details: Ladder Bar, Santhuff Double Adjustable on all 4, 150 springs on the front, 406, Glide, 1600lb. rear weight, 19" rear shock length. 1700lb front weight.

Mark

Re: Rear Coilover Spring Rate Help
 

Reach out to Marty Rinehart at Rinehart Performance. They sell and work with Santhuff on all kinds of combos.

Re: Rear Coilover Spring Rate Help
 

I have asked them and they recommend 125# and Santhuff had recommended a 150# spring along with a few others. However I want someone to explain why use a specific rate and how it should affect the car.

Re: Rear Coilover Spring Rate Help
 

Mark. You’re car is gonna work just fine trust me!

Re: Rear Coilover Spring Rate Help
 

There are good technical pages on the Chris Alston chassis site. Info on choosing spring rates and setting up coilovers.

Re: Rear Coilover Spring Rate Help
 

Isn't the theory that you want the lightest spring that will hold the car up? That will most easily allow your ladder bar and shock adjustments to do their thing without unnecessary resistance from the springs.

Re: Rear Coilover Spring Rate Help
 

correct

Re: Rear Coilover Spring Rate Help
 

So your saying as long as the spring doesn’t coil bind and has enough room for compression for bumps that’s the best spring?

Re: Rear Coilover Spring Rate Help
 

What Lenny said ^^^^
Use the shock adjustment/valving for bumps..

Re: Rear Coilover Spring Rate Help
 

For any situation, there will be 3 or more spring rates which will support the car at the desired ride height with the shock at the the desired center to center (which should be maintained). This will have the different rate springs compressed to different heights. Compressing a spring stores energy which makes the suspension more "lively".

Heavy springs compressed a little will react differently than light springs compressed more. Which you use depends on many things in your combination and personal preference. Lighter springs will usually require better shocks to control the housing, especially with ladder bars, certain 4 link settings and/or higher power levels, allowing you to tune it accordingly.

Marty's recommendation of 125# on that 14" spring (I assume) and the Santhuffs is likely spot on.

Re: Rear Coilover Spring Rate Help
 

I bought a set of D/A Koni's Bickle valved in the late 90's. He suggested a 175 on this all steel Nova.

If you look at his spring recommendations in one of his catalogs, 1500-1800 rear weight he suggests a 175.

I did put a 125 spring on this to run some local 370 Pro Tree races. It did work for the fast tree, however it acted more so than previously, like it needed a ARB. Ladder bar sbc 10x28 bias, 3200 lbs.

Eibach or PAC coilover springs are the good ones, if you can find PAC, they've stopped producing , coil springs.

I just bolted a set of PAC 165 on this, i bought and made one hit on in 2017, went 1.28 60ft last car down on a Thursday night test n Tune prep n/a sbc. 1550 lbs on back tires.

Not criticizing anyone's suggestions here, just stating my experience, light vs heavy spring.



https://i.imgur.com/o1JP9bM.jpg

Re: Rear Coilover Spring Rate Help
 

OP stated he was using a 19" shock. I made some assumptions from that as far as shock travel, installed length at ride height, spring free length and compressed length at ride height, etc. All of which make a difference.

Re: Rear Coilover Spring Rate Help
 

Mike Rietow

Give me a call when you gat a chance. I would like to discuss further.

Mark
210-392-9902