Spring Rates (rear)

[Hodrod7]

When changing from a 10" spring to a 16" ish spring what changes would need to be made with the spring rates? (Running 175 lbs 225 lbs now)

[let-r-eat]

What's the compressed length of the 225lb spring at ride height?

[Hodrod7]

Not really sure the total compression of each spring right now. (Car is tore apart for the winter) I read on a forum page someone had, there was a way to measure compression and figure what spring you would need! Their example was something like 13" 200 lbs spring would be a 16" 100-125 lbs spring. (Using a equation they came up with to get that). Stock car driver I should forget I saw that forum page and go with what the car knows and use what I have now just taller? (Trying to get more forward bit)

[Confused?]

SCD is correct. A 200 pound spring is 200lbs/in,doesn't matter if it is five inches long or twenty inches long

[fastford]

I think your wanting more stored energy, by using a taller, weaker spring and maintaining your current ride height and spring seats. this is not hard to figure out if you know your specs for your 10 inch spring,

[Hodrod7]

Gotcha! Thanks everyone for your help!!

[Hodrod7]

Guess now the question would be... Is 16" what I should go with? Height isn't a issue, I have adjustable bucket with a 10" spring now.

[fastford]

That only comes into play if a spring is becoming unloaded like a 4 link car.

Daaa , once again , thanks for clarifying my statement with you expert knowledge....just remember, 2 can play that game.....

[Hodrod7]

More bite! Always struggled with pull off the corner! Guess I'm just going with the trend of what some of the front runners seem to be doing! Going threw the car this winter and wanted to try taller rear and softer front. (RF 1300 lf 1100 now.)

[Hodrod7]

Is that why guys are running say RF 900 and LF1000? I saw a thread were someone posted that you had a thread about spring rates! I couldn't seem to find it! Instead of me asking dumb questions is that thread still around?

[fastford]

I doubt it, Ive erased all my posts on here several times..

I would start
900/800
275/250

that's a conservative start that a lot of people have tried and liked. Spring rates can vary based on how high your motor is mounted, cell, even the cage etc. The last car I built myself everything was really high, I had to run stiffer springs in that car than my previous car.

you had a post a while back that you said you were about to retire from driving, I can see why with that 10 year old set up. theres stock cars down here on way softer springs than that and flying. it may not be a late model, but some of the modern day late model stuff works on stock cars to.

[Hodrod7]

I appreciate your help!!

[Hodrod7]

Fast ford what's your spring package?

[let-r-eat]

If the 10", 225 pound spring has an installed height of 8.5" there would be 337 pounds of preload on the spring. Going to a 150 pound spring that is 16" long would have an installed height of roughly 13.75 inches requiring 5 1/4 inches of jackbolt available to maintain the same ride height.

[fastford]

Fast ford what's your spring package?

the car that's winning a lot of races all over the south east is on a 400 lb right front with a bump stop , I know this for a fact , I don't know what rt frt shock he is on but Im sure its a high rebound shock.