Thread: 250lb springs on highboy makes sky jacker ad

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ok i put on my coil overs (qa1) with 250 lb springs on a 30 degree angle at ride height ..did all my homework for setup with sag and such ......my car is 2 inches taller in the rear then planned.....looks like either a car from the 70s or a good candate for the air shock ad..

my question is do these settle? i noticed a small diffence this morning since yesterday. but i ALSO own 165 lb springs as well ...do i need to try those to get my desired ride height ??

please help...

I used 300's in the front and 150's out back.

so i guess my 165s should go in the rear huh...

The springs and suspension will settle in some, but for a light car, the 250# are plenty big.... Try the 165# springs.

Amen on the plenty big. Something in the range of 165 would probably be close on a highboy.

However, check how much your shocks compress under full load. They should drop to about 1/3 of total travel. If you go lower than that, they can bottom out on a bump. If you go less, they can top out on rebound.

The way I do it is, I want my ride height in the center of the travel of the shock. So I start off withe a piece of tubing and drill two holes in it representing the ride height. Set the car at the ride height I want, then do my shock mounts. Then spring it to that height. My roadster weighs 2440# and I use 180# Springs and sits in the middle of the shock stroke. In my opinion that is the correct end result.

[QUOTE}my question is do these settle?[/QUOTE]

Springs do not settle. Sagging suspension is due to spring over exertion, that is stress beyond the springs limit (like hitting pot holes, or overloading the trunk with bags of cement on a Home Depot trip).

A 250# will absorb energy at a rate of #250/in.
If you put 500# on it - it will store 500# of potential energy by dropping 2 inches. This assumes the spring sits at 90 degrees.

A 30 degree offset reduces the downward force on the spring by 30%.
So now it only stores ~333 pounds of energy and drops only ~1.3 inches.

At least that's the theory behind the issue -

The experienced builders here know exactly what is needed.

Originally Posted by Ken Thurm

The way I do it is, I want my ride height in the center of the travel of the shock. So I start off withe a piece of tubing and drill two holes in it representing the ride height. Set the car at the ride height I want, then do my shock mounts. Then spring it to that height. My roadster weighs 2440# and I use 180# Springs and sits in the middle of the shock stroke. In my opinion that is the correct end result.

Ken,

Most shock manufacturers advise the ride height to be above the 50% mark. The 1/3 figure I gave earlier is pretty common. No biggie, though if 50% works for you.

thanks for the helfull tips guys im gonna try the 165lb springs first since i own them . and ill post my progress later ..

put the 165 springs in and the sits nice and where i want it to . i jumped in the car a bunch of times and the car feels good for spring rate ...so far but that will also be determined with fuel , my butt, and battery and some bumps and accelleration too..

How much of your shock travel did you use up at ride height?

id say a 1/3rd of it and that is with the adjusters all the way down

The instructions that came with my Aldan Eagles recommended 55% in bump and 45% in rebound, so that's where I put 'em.

Tech,

I just pulled the instructions out for my new front Aldan Eagles:

When designing your suspension mounting points, extend the shock to 1/3 at ride height; i.e., if stroke is 3 inches, set the car up so that at ride height, the shock has room for 2 inches compression and 1 inch rebound.

Same manufacturer, different instructions.

Okey Dokey, works for me.