[Conan]

Whats the difference between bbk's progressive rate and specific rate springs, also which is better for my 95 Gt, i just want something to get a better stance and i want the car to handle better, i also want something that handles better, ill be upgrading the rest of the suspension later, but just want something for looks right now

[DaleBrown]

Here is an interesting article written for the 928 on specific vs progressive springs but general idea is the same.

http://ourworld.compuserve.com/homep...ols/tip334.htm

Hope this helps ..

[GTRaptor]

In fewer words:

Progressives are meant to be very soft when not compressed, giving a nice ride quality. When they do compress the "rate" increases, that means they get harder.

Linears on the other hand are always working at the same rate.

Linears are PREDICTABLE, thats why roadracers choose them. Progressives are not, as the above article explains.

For cornering stability linears are the way to go.

For a STREET mustang, a linear front springs should be around 600, 650 lbs. and should use performance struts such as KONI, BILSTEIN or TOKICO adjustables.

For the rear it will depend on the combination of parts. If you use urethane control arms a rate around 200-230. With Global west or MM arms around 170-200.
If you use a panhard bar you need them to be stiffer, around 250-300 lbs for the street.