Spring Ratings and length

[martinlaw]

Having stripped the shocks/springs from both my Sport and GTR I now have a bit of a dilemma.

Standard Ultima springs are 180 x 80 at the front and 180 x 110 at the rear (thanks for the info Pete -Lucky).

Now, the Sports spring ratings are 180 x 80 at the front and 180 x 140 at the rear.

The GTR spring ratings are 225 x 110 at the front and 225 x 150 at the rear.

I also have a spare set of 180 x 110 springs.

What do i do!!!!

Since I want to use the GTR on the road and track I am unsure what to do?

Questions:

1. What is the difference in performance between a 225mm length spring and 180mm.
2. Since stiffer springing is better for the track, should I keep the front standard but stiffen up the rear (since there is more weight here) by using the 180 x 140 springs?
3. Keep to standard Ultima ratings?

Any guidence would be appreciated,

Cheers
Martin.

[ezakimak]

put them in the car and go for a drive.
go with what feels better.

ETA

You need to insure that the spring will not “Coil Bind” when it is installed and the suspension reaches pull bump travel. If it coil binds each individual turn of the coil spring will contact the adjacent coil. When this happens the spring rate will go through the roof, and you will get no more suspension travel....car exits stage left

When looking at the coils the size or diameter of the wire will give a fair indicarion to the stiffness of the spring. Larger diameter wire will generally result in a stiffer spring.

I still dont fully understand what the spring details mentioned mean. You might need to convert them into natural frequencies and consider them with respect to the chasis and suspension design.
Hope that helps

regards ryan

Edited by ezakimak on Tuesday 10th June 09:17