Technical Rear coilovers

Looking for advise on what weight range coilovers to use on the rear of my '32 5w. Channeled, with the tank in the trunk behind the seat. I have been told to go with the lighter (200Lb) for the best ride. Was the guy right?

 

I run 250lb. springs in my 1930 A sedan. I have 1 new 225lb. spring for sale in the cl***ifieds - shameless plug!

 

Mine are mounted at 29 degree's - you need to tell us your angle before we can properly advise you.

 

When I was trying to decide which ones to use on my roadster I went to Speedways website. They have a chart on it for you to use to estimate the weight of your car so you can decide which coil over to use. Takes into account things like AC and so on... Ordered mine using that info for a 1931 Ford roadster I am building. Also, depending on if they are mounted straight up or at an angle you can loose efficiency on their dampening ability. Think there was a chart for that too!

 

Sock length is a factor, springs are in 'lbs per inch' so if your shock takes up 3" or 2" makes a big difference in rate. The spring is supposed to support the wieght and leave the shock near the middle of travel. Suppose the rear weight is 1000lbs, the total travel (stroke) of the shock is 6". That means you'll want to support 1000lbs on 2 tires = 500lbs per tire, 3" of travel to center the shock so 3/500lbs = about 165lb spring rate. If you had 2" of travel then it'd be 250lb to get you in the same place.

 

Ride tech has a nice spring calculator chart. I'm at 150lb rear springs with Bilstein coil over shocks. Bilstein shocks are nitrogen charged, so you can add roughly 25lbs of spring rate to your calculation.

 

believe 250lb will be too stiff.

 

About 120lb/in wheel rate for a lightweight car.
Weigh the rear, then jack the rear up and weigh the wheels [without springs installed] to get the unsprung weight.
For a comfortable ride you need about 4-1/2" to 5" of load. [the amount it settles with weight on it ]

so a car that has 1500lbs rear weight minus 300lbs unsprung weight has 600lbs on each spring.
600lbs divided by 5" = 120lbs/in wheel rate.

This is the wheel rate, you will need to factor in the motion ratios [ shocks laying down etc ]

 

When it came time to put coil overs on my 2000lb coupe I called pete&jakes.They were very helpful and the viper coil overs have been on there 12 years now...............