Progressive or Specific Rate?

[sixty9boss302]

My buddy has a 91 GT and he wants to get a set of springs. The question is, what is the diff between specific rate and progressive rate in terms of ride quality and handling. The priciple is easy...progressive just means that the spring becomes harder and harder to compress throughout its travel, and specific rate just means that the compression rate is the same throughout the entire travel of the spring. So which is better for normal street driving, maybe a couple weekends at the track? Any help would be great thanx!! Five-0 FO' SHO'

 

[drgn5.0]

Specific is for performance, progressive is for looks i guess.

 

[Maryland Stang]

It's all in what the guy wants. If he's going to be daily driving the car go with the progessive rate. It will give him a better ride and it's easier on the car. I only have FMS "B" springs (200-300 rear, 425-530 front) and the expansion joints on a concrete highway will beat you to death. Bump-bump, bump-bump, bump-bump for 40 miles....

But if he doesn't care about feeling every little ripple in the pavement then go with specific rate.

 

[DShoop]

My buddy has a 91 GT and he wants to get a set of springs. The question is, what is the diff between specific rate and progressive rate in terms of ride quality and handling. The priciple is easy...progressive just means that the spring becomes harder and harder to compress throughout its travel, and specific rate just means that the compression rate is the same throughout the entire travel of the spring. So which is better for normal street driving, maybe a couple weekends at the track? Any help would be great thanx!! Five-0 FO' SHO'

I've used both. Have a set of Eibach progressive rate springs sitting here and a set of Kenny Brown specific on car. Ride qaulity is more specific to the shocks and struts. You have to upgrade to a high qaulity shock strut setup either way. Handling is much more predictable with the specific rate springs and slightly more comfortable with the progressive. My suspension is stiff, but for handling it can't be beat.