[RedSilver88]

What is the difference between different spring rates.(progressive, performance, ect...)

[Twister]

a linear rate spring is one with the same rateing throughout the spring, a progresive spring starts soft and gets harder, for instance, it takes 300 pounds to compress the first inch of the spring, and it takes 600 pounds to compress the last inch of the spring. as for "performance" springs, all springs can be "performance" springs, depending on the shocks/struts and chassis bracing, Lotus uses very soft springs while allot of tuners use hard springs....

[bob8797]

http://home.satx.rr.com/davidmroe/sp...ufacturers.htm

[GTRaptor]

Progressive springs are more for comfort than performance. Their characteristics might make them unpredictable under racing conditions.

Most racing vehicles will use LINEAR rate springs.

The thing with linears or progressives is to choose the right ammount of "weight".

Stock Mustangs use front srpings of around 450-530 lbs, rears around 200-230 lbs.

You should select springs that match your driving habits, suspension mods and road conditions.

Front spring rates around 600 are ok for the street and ocassional road racing or autoX. Dedicated RR will go from 700 to 800+ front springs.

Rear selection depends on the type of suspension you will use. Panhard setups will require 250-300+ lb springs. While more conservative setups without panhards can do great with SOFT springs with 200-150 lbs.

Springs, control arms, swaybars and shocks/struts have to be combined to get the desired effect.
Stiff springs require better valving struts and shocks (Koni adjustables-Bilstein). While softer setups can do ok with cheaper ones (TOKICO non adj, KYB, Monroe).

So, choose wisely, go with kit combinations that are proven to work: Maximum Motorsports, Steeda, Global West.

[Saleen Owner]

My car came stock with Racecraft static rates all around, and were
very consistent on the track. That said, I found them down right dangerous on the street. Most corners in the area I live are fairly
rough, and the statics had a nasty tendency to kick out the tail without
warning. I put progressives on (Racecraft) I was amazed. The ride
is still very rough but you can feel the car so much better. I can get
alot closer to the edge, 4 wheel drift as aposed to kick-out. My Solo II
times droped and only drawback was a minor loss of throttle steer,
which I got back in spades with addition of a Saleen panhard.

[GT Dan]

Spring rates will differ if you consider a coil-over system. On the rear of the car the spring in a coil-over-shock setup is relocated so that the leverage to compress is significantly less, so a lighter rated spring is needed. The coil-over set-ups look nifty....I haven't driven one....but the ability to adjust ride height sounds appealing for varied applications. Is anyone running one or driven one and can provide feedback?