MustangWorks.com : Ford Forums - View Single Post - What's the difference in "Progressive" vs "Specific" rate lowering springs?

Conman · 11-18-2002, 01:17 PM

lx5091 did a pretty good job of describing how they are different
this is just a couple points to add in
specific rate springs have one spring rate thoughout the entire spring and a linear response (i.e 650lb/in) so in this case it would take 650 lbs to compress the spring one inch and another 650 lbs to compress it another inch.
Progressive rate springs do not have a linear spring rate. I don't know exactly what the rates are but it may only take 300 lbs to compress the spring the first inch and then as you compress it more you would work up to say 650 lbs per inch.

Progressive springs are better for someone that wants to increase looks and handling a little while maintaining smooth ride qualities.

Specific rate springs are better for someone looking for more performance and better lowering qualities and willing to sacrifice the smooth ride quality a little bit.

The BBK springs I have are specific rate 650 lb/in and I like them. They are not too harsh and I think specific rates are also cheaper.

11-18-2002, 01:17 PM	#4
Conman Registered Member Join Date: Apr 2002 Location: Kingston, Ontario Posts: 351	lx5091 did a pretty good job of describing how they are different this is just a couple points to add in specific rate springs have one spring rate thoughout the entire spring and a linear response (i.e 650lb/in) so in this case it would take 650 lbs to compress the spring one inch and another 650 lbs to compress it another inch. Progressive rate springs do not have a linear spring rate. I don't know exactly what the rates are but it may only take 300 lbs to compress the spring the first inch and then as you compress it more you would work up to say 650 lbs per inch. Progressive springs are better for someone that wants to increase looks and handling a little while maintaining smooth ride qualities. Specific rate springs are better for someone looking for more performance and better lowering qualities and willing to sacrifice the smooth ride quality a little bit. The BBK springs I have are specific rate 650 lb/in and I like them. They are not too harsh and I think specific rates are also cheaper. __________________ '88 lx, Black on Black, check it out here Spent all my money on school, what a dumb mistake I'm old enough to know better, but still too young to care.