I run a double adjustable coil over on the rear ( Ladder bar car ) the springs are 130 lbs the rear of the car weighs 1550 lbs what rear spring should I be using?

This message has been edited. Last edited by: eric doukas,

Where are the shocks, in front or behind rear axle?

behind

Alston chassis had a good formula on their site.
How long is your spring at rest and how much does it compress with the weight of the car on it?

https://www.cachassisworks.com...899-031-226_drag.pdf

This message has been edited. Last edited by: Eman,

I would say your good with the 130's. Would not go any lower.

When I first read it I thought you had a 1500 pound roadster. After re-reading I see you have that weight on the rear.

Never scaled my car, but at 3200lbs or so with driver I run 130's in my ladder bad car also and it is perfect.

A super well known chassis SS/Stock builder told me the biggest mistake most race cars have is that the rear spring/shock is too stiff. He said it would scare me to death to know how soft a lot of the REALLY fast cars are set.

For what it's worth.

I just got the Rick Jones book he has out. It states/
1200-1300 Spring rate 125 lbs
1300-1400. 150 lbs
1400-1500. 175 lbs
1600-1800. 200 lbs
I have a back half chevy2 and it has 150s in it. Hope this helps

My '68 short bed pickup now has 125 springs in the rear. I started out at 250 then went to 175. We had it back halved with a narrowed rear and the fabricator out 125's in it after he scaled the truck. It has to pop the front wheels, now it just picks them up about 6 inches and carries them. Smooth as a baby's butt.

How much are your springs compressing with those heavy springs?

quote:

Originally posted by Eman:
How much are your springs compressing with those heavy springs?

I have used a tie strap to see how much the shock was compressing.

quote:

Originally posted by ollies69:
I just got the Rick Jones book he has out. It states/
1200-1300 Spring rate 125 lbs
1300-1400. 150 lbs
1400-1500. 175 lbs
1600-1800. 200 lbs
I have a back half chevy2 and it has 150s in it. Hope this helps

Is that the weight sitting on the springs which does not include the 3rd member weight ??

quote:

Originally posted by ollies69:

quote:

Originally posted by Eman:
How much are your springs compressing with those heavy springs?

I have used a tie strap to see how much the shock was compressing.

I mean from weight off the ground and how much the spring compresses when you place the car on the ground. Springs are supposed to be compressed at rest to have stored energy. Most videos of suspension show extension until you let off or hit a bump.

quote:

Originally posted by markemark:

quote:

Originally posted by ollies69:
I just got the Rick Jones book he has out. It states/
1200-1300 Spring rate 125 lbs
1300-1400. 150 lbs
1400-1500. 175 lbs
1600-1800. 200 lbs
I have a back half chevy2 and it has 150s in it. Hope this helps

Is that the weight sitting on the springs which does not include the 3rd member weight ??

I think he was referring to scaling the car with the rear wheels on the ground.

quote:

Originally posted by ollies69:
I just got the Rick Jones book he has out. It states/
1200-1300 Spring rate 125 lbs
1300-1400. 150 lbs
1400-1500. 175 lbs
1600-1800. 200 lbs
I have a back half chevy2 and it has 150s in it. Hope this helps

Assuming those are for the shocks mounted behind the rear end, they are high! You can't list a table like this without all the info behind it.

130 springs for a car that has 1550 on the rear tires is good.

quote:

Originally posted by TOP38:

quote:

Originally posted by ollies69:
I just got the Rick Jones book he has out. It states/
1200-1300 Spring rate 125 lbs
1300-1400. 150 lbs
1400-1500. 175 lbs
1600-1800. 200 lbs
I have a back half chevy2 and it has 150s in it. Hope this helps

Assuming those are for the shocks mounted behind the rear end, they are high! You can't list a table like this without all the info behind it.

130 springs for a car that has 1550 on the rear tires is good.

In a 4 link car with shocks behind axle and vertical mounted with a weight of 1265 on the rear wheels, what do you believe is the minimum spring weight that could be used ??

I did the Alston Chassis formula that Eman posted and it says 123.5 for my car.

quote:

Originally posted by TOP38:

quote:

Originally posted by ollies69:
I just got the Rick Jones book he has out. It states/
1200-1300 Spring rate 125 lbs
1300-1400. 150 lbs
1400-1500. 175 lbs
1600-1800. 200 lbs
I have a back half chevy2 and it has 150s in it. Hope this helps

Assuming those are for the shocks mounted behind the rear end, they are high! You can't list a table like this without all the info behind it.

130 springs for a car that has 1550 on the rear tires is good.

I posted the chart as RJ had it. Most if not all 4 link cars and ladder bar car have the shocks behind the rearend. What else would you like me to look up in the book. I just posted it as it was in the book as a general reference.If I knew how to take a pic of the page and post it I would. LOL

quote:

Originally posted by markemark:

quote:

Originally posted by TOP38:

quote:

Originally posted by ollies69:
I just got the Rick Jones book he has out. It states/
1200-1300 Spring rate 125 lbs
1300-1400. 150 lbs
1400-1500. 175 lbs
1600-1800. 200 lbs
I have a back half chevy2 and it has 150s in it. Hope this helps

Assuming those are for the shocks mounted behind the rear end, they are high! You can't list a table like this without all the info behind it.

130 springs for a car that has 1550 on the rear tires is good.

In a 4 link car with shocks behind axle and vertical mounted with a weight of 1265 on the rear wheels, what do you believe is the minimum spring weight that could be used ??

I did the Alston Chassis formula that Eman posted and it says 123.5 for my car.

Mark Mark So that chart is very close

My 4-link car is around 1250 on the rear. Shocks behind the axle. I was running some 130 pound springs and felt they were still too stiff. Put in some 110 springs and the car loved them.

Springs hold the car up. Adjustable mounts allow you to control the ride height. Shocks do all the work. If the springs are too stiff, the shocks don't do as much work.