Skyjacker Coil Spring rate Question

[GordoSmasho]

I know if you shorten a coil it will increase its spring rate but i'm just wondering how much. I have a set of 8 inch skyjacker coils and i'm looking for 5.5 to 6.5. If I cut them down am I going to have a hard time flexing them out or will it not matter that much? I'm only cutting 2.5 off max.
This may sound stupid but i'm on a stupid amount budget.

 

[RCP Phx]

Skycrapper is bad enough w/o increasing the spring rate!

 

[jamiemac]

Edit to add: Looks like I gave some bad info here. I Try to avoid that but I was just wrong here.

 

[RCP Phx]

You should call skyjacker and ask if they are variable or straight rate springs. If the are straight, then it will make no difference, but variable will get stiffer the more coils You cut. A good rule of thumb to tell which they are is, variable rate springs have upper coils wound closer together and get spaced further apart on the lower coils.

Wrong,any removal of coils will increase the spring rate regardless of how they are wound!

 

[jamiemac]

Wrong,any removal of coils will increase the spring rate regardless of how they are wound!

Not what I was taught years ago, but after thinking about it I can see where it's wrong. The shorter a piece of metal is, the harder it is to bend, so it makes sense that that the shorter You cut a spring, the more You increase its rate.

I'll amend the above post.

 

[trippled]

ive always heard you can get away with cutting off half a coil but even that is a pretty different spring rate.

 

[Goatman]

I know if you shorten a coil it will increase its spring rate but i'm just wondering how much. I have a set of 8 inch skyjacker coils and i'm looking for 5.5 to 6.5. If I cut them down am I going to have a hard time flexing them out or will it not matter that much? I'm only cutting 2.5 off max.
This may sound stupid but i'm on a stupid amount budget.

I ran 8" Skyjacker coils on the front of the XJ with one full coil cut off. It gave me roughly 5.5" of lift, and that is with a very heavy front bumper and winch. I ran that coil for a long time running hardcore rock trails and some go fast stuff. It was good for go fast, plenty good for hardcore crawling (never lost any capability over softer coils), and was just a little stiff on the easier camping type trails in the Sierra's but still just fine.

 

[4.3LXJ]

I have a set of Skyjacker 6" coils that really are 7" minimum of lift. They are stiff, but I have kept the weight down on the front. I bought some RE 7.5" coils and they are much softer and the same height. I can tell you that if I cut a coil off it would just be too much. Why don't yo just trade them to somebody and get what you want?

Also on coil springs, the flex is dictated by the length of the wire and diameter of the wire. The twist on the wire starts out soft and increases. So a long wire, ie lots of coils only require a wire to twist a little. By cutting off coils, the wire must twist more for the same amount of travel and so the rate goes up.