Let's get one single thread going on this subject. More leaning towards what's better for certain types of driving, personal preference, etc.

Is it better to have stiffer springs up front or in the rear and why? For me, I'm a street/road race/autocross guy. Also, I'm a fan of coilovers vs. struts/shocks and springs.

Chime in with thoughts, experience, suggestions, etc.

Hoping Sam Strano gets in on this.

Thanks.

 

I measured the spring rates of a 2010 GT, 2010 GT500, CDC kit, FRPP kit, The stiffer spring was in the front. I do not believe Ford has ever sold a s197 with the rear springs stiffer than the front. It is real easy to explain a publishing error that gets repeated because nobody has actually made the effort to measure the spring rates themselves it is much harder to explain how a factory can put stiffer springs on the back but every after market supplier sells springs that is stiffer in the front. And we're not talking a couple pounds here. And these springs don't have enough pre-load as installed to compensate for the low rates Ford reportedly uses. When I asked Dean Martin about the reported spring rate for the 302 he laughed and said it was an error. The springs are stiffer in the front and whats more he was a suspension engineer at Ford before he quit to go to Rehagen Racing.

 

Hmm that's interesting. Thanks for the info.

 

Eibach did these installs on a 2011 GT. Both times, it says Eibach had stiffer springs in the rear.

http://performance-suspension.eibach...d_mustang_2011

http://performance-suspension.eibach...d_mustang_2011

 

Weird info from Eibach.

Rehagen is running 500 lbs front springs and 350 lbs rear according to Dean on their race cars.

Measuring spring rates can be weird. See if the spring is designed to coil bind the rate changes drastically. Some springs are designed to coil bind in the pre-load stage in other words just mounting them causes the coil bind. If this is the case you can't count the rate of the spring until you have it as mounted. You notice in the picture of the Eibach spring they have what they call helper spring kind of inappropriate name but any way those are completely closed once the suspension is mounted up so they have no effect on the spring rate and the reason they are so skinny and often wound from flat wire. The CDC springs on the rear of my car have a section of spring which is in essence a "helper" spring. The coils are so close together that once mounted that part of the spring is no longer live it is a dead coil. Any time a coil closes completely it is a dead coil and it no longer effects the spring rate. The spring is effectively a shorter wire and shorter wire is effectively stiffer. When measuring spring rates you have to get the spring down to it's as run height.

 

Anyone else have any input?

 

Here are the spring rates for our Springs:

555-8206 Steeda Ultra Lites - 195lb front, 175lb rear
555-8215 Steeda Sport Springs 200lb front, 175lb rear
555-8220 New Steeda 05-12 GT Convertible sport springs 200lb front, 190lb rear
555-8245 - New Steeda Comp Springs Boss 302 and GT 225lb front, 195lb rear.

Stronger spring rates will give you better handling and once you increase it to a high enough rate you will need better shocks and struts to achieve proper wheel control and maintain ride quality.

Our Springs are still on sale

 

Here's what Ford put on the cars 10-12.

If you don't have excel, google excel viewer and install that.

 

So the GT500 is the only one that comes with stiffer front springs stock from the factory? Interesting.....

Thanks for the info

 

Might be do to the extra weight of the blower, intercooler, fans, fluids............

 

Fact.

 

I'd love to know what the FRPP spring rates are.

 

Vogtlant Sport Springs:

*NOT the leveling springs they make....the drop springs.

........Spring lb/inch.......................Working Rate lb/inch..............Drop Front/Rear
Front: 160 lb./in. - 240 lb./in.........180 lb./in. - 240 lb./in.............1.2" or 30mm
Rear: 120 lb./in - 220 lb./in...........180 lb./in. - 220 lb./in.............1.2" or 30mm

Anyone Ever use these?