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Spring Rates ???

Here is a starter list from another thread on this forum:

Mustang GT (2011+) Stock: Ft 122 lbs/in Rr 154 lbs/in *
Brembo Stock: Ft 131 Rr167 lbs/in
Boss Stock: Ft 148 Rr 185 lbs/in
Boss LS Stock: Ft 137 Rr 191 lbs/in
Eiback Pro-Kit: Ft 159 Rr 193 lbs/in *
M- 5300-K rate: Ft 173-248 lbs/in – Rears 195-236 lbs/in
Steeda Competition: Ft 225 Rr 185 lbs/in
Steeda Sports: Ft 200 Rr 175 lbs/in
Steeda Boss Springs Ft 225 Rr 195 lbs/in
Steeda Ultra-lite (pn 555-8206) 1.25/1.5 front: 195lb/in / rear: 175lb/in

* Sourced from Maximum Motorsports website.

I would recommend that sources be cited and that a master list be kept on the first post or at least first page.
 
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Adding to the list:

FRPP P Springs: 204lb/in 165lb/in *Vorshlag Tested
FRPP K Springs: 188lb/in 221lb/in *Vorshlag Tested
Eibach Pro street Coilover: 225ln/in 90-200lb/in *Eibach Spec sheet
Eibach Pro R1: 225lb/in 250lb/in *Eibach Spec sheet
H&R RSS Clubsport: 630lb/in 515lb/in *H&R Spec sheet
302S: 600lb/in 350lb/in *Official Ford 302S manual
Suspension Techniques/KW V1/2/3: 342lb/in 200lb/in *KW confirmed with me directly. Rates are @ static load/ride height

Now...does anyone know the motion ratio on our cars to calculate wheel rate?
Mac strut traditionally has been something around 0.95...so our front is roughly that. But how about the rear?
 
Possibly the right place to ask this; where are people going for custom or more specific rates of springs. I know my dads car has hypercoils but they are for a coilover setup.
 
All replies put in one place. Thanks for the help and info. If there are any missing add them at the bottom.


Mustang GT (2011+) Stock: Ft 122 lbs./in Rr 154 lbs./in * Source, Maximum Motorsports
Brembo Stock: Ft 131 lbs. /in. Rr 167 lbs./in
Boss Stock: Ft 148 lbs./in. Rr 185 lbs./in
Boss LS Stock: Ft 137 lbs./in. Rr 191 lbs./in
Eibach Pro-Kit: Ft 159 lbs./in Rr 193 lbs./in * Source, Maximum Motorsports
FRPP K Springs: Ft. 188 lbs./in Rr 221 lbs./in *Vorshlag Tested
FRPP P Springs: Ft. 204 lbs./in Rr. 165 lbs./in *Vorshlag Tested
Steeda Competition: Ft 225 lbs./in. Rr 185 lbs./in
Steeda Sports: Ft 200 lbs./in. Rr 175 lbs./in
Steeda Boss Springs: Ft 225 lbs./in. Rr 195 lbs./in
Steeda Ultra-lite: Ft. 195 lbs./in. Rr. 175 lbs./in
Eibach Pro street Coilover: FT. 225 lbs./in Rr. 90-200 lbs./in * Eibach Spec sheet
Eibach Pro R1: Ft 225 lbs./in Rr 250lbs./in * Eibach Spec sheet
H&R RSS Clubsport: Ft 630 lbs./in Rr 515 lbs./in * H&R Spec sheet
302S: Ft 600lbs./in Rr 350lbs./in * Official Ford 302S manual
Suspension Techniques/KW V1/2/3: Ft. 342lbs./in Rr 200lbs./in * KW confirmed. Rates are @ static load/ride height
 
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Brandon302 said:
What does static ride/load rate mean? Is that before compression while riding?

Right - it means spring rate at ride height...with the coils compressed by the weight of the car.
It is traditionally the way progressive rates are measured.

RE: T springs - I thought it was a P front and K rear as per P/N's listed on the spring?
Or am I crazy? I thought I had read that somewhere...
 
boro92 said:
Right - it means spring rate at ride height...with the coils compressed by the weight of the car.
It is traditionally the way progressive rates are measured.

RE: T springs - I thought it was a P front and K rear as per P/N's listed on the spring?
Or am I crazy? I thought I had read that somewhere...

Rears are K but the fronts are their own beast.
 
boro92 said:
Right - it means spring rate at ride height...with the coils compressed by the weight of the car.
It is traditionally the way progressive rates are measured.
Thanks, so I assume they get stiffer as they compress?
 

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