# Spring rate?

Discussion in 'The Garage' started by DesertDueler2, Jan 4, 2007.

1. ### DesertDueler21/2 ton status

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Does anyone know what the spring rate is for the rear springs of trucks, or K5s? Preferably say a 87 K5 with 52s, or a 3/4 ton truck with 56" Springs.

Dan

2. ### iwaxmyjimmyCollege web wheelerPremium Member

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dunno the caculator for it. but its determind by the lenght of each leaf, thickness, and number of leaves .

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ttt

4. ### ntsqd1/2 ton status

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Leafs aren't linear in spring rate. The weight/force needed to compress the first inch will be less than the weigh/force needed to compress them the last inch.

That being said, measure the ride height at a point like the center of the fender opening lip. If you're really anal about this, put some masking tape with a mark on it so that you measure in exactly the same place everytime. Stack weight directly over the axle until you get one inch of compression. If it's not over the axle then the weight is leveraged & the math gets uglier. Weigh all the pieces/chunks and divide by two to get the effective spring rate.

5. ### DesertDueler21/2 ton status

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Well, I am getting ready to do coils in the back, and want to keep with the same spring rate more or less.

Dan

6. ### iwaxmyjimmyCollege web wheelerPremium Member

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id go a with a long soft coil just for a lil more flex.maybe something from the front of a je*p TJ or cherokee. maybe something along the lines of a 6-8 inch spring. but thats my own opinion.

7. ### ntsqd1/2 ton status

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I wouldn't even mess with stock application springs. With those you have no control over spring rate.

Use coil-over coils. You can get them in a variety of different spring rates, and as long as you haven't marked them most vendors will exchange them for different rates should you not get exactly what you wanted on the first try. There are commonly available springs for 2.0" c-o bodies, 2.5" c-o bodies, and 3.0" c-o bodies. If you expect to need a really long coil then use springs for one of the bigger c-o bodies as they will be a larger OD.

8. ### DesertDueler21/2 ton status

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In the back of the spring books it tells you the spring rate of each spring and if it is variable or not. SO using a stockk aplication should be fine for me. If I could afford coilovers I would, but so far I have \$30 into my project. It is on 3/4 tons already, have the stuff to either propane inject a big block, or have a complete TBI SBC with an aftermarket harness. I just cant see spending \$1000 on a set of coilovers, or atleast not at this time. Maybe when it gets rockwells

Dan

9. ### ntsqd1/2 ton status

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I'm not talking using coil-overs, just their springs. Those springs come in 25 to 50 lbs rate increments allowing you to dial in your exact spring rate.

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