You want the coil spring rates to match within 10% of what the shocks/struts are rated for. Example:
The '03 Cobra coupe front Bilstein struts are valved for the 600lb coil springs the coupe has from the factory. The KB front spring rates are 650lb. The extra 50lbs of spring rate is within the 10% difference allowed, so they work well together. Any coil spring over 660lb rate would be too stiff for the '03 coupe strut.
The '00 Cobra R rear shocks are valved to work with the 750lb rate of the '00 R's rear springs. This is within the 10% difference to the KB springs, which are about 800lb. The '03 Cobra coupe rear shocks are valved to match a 600lb spring, which is outside the 10% diff. limit - 750 - 600 = 150. Divide 150 by 750 = 20% difference.
You may also want a little smoother ride, but make sure you match the spring rate(s) of the set you pick with what the struts/shocks are rated to handle.
quote:
--------------------------------------------------------------------------------
Originally posted by whitesnake
What are the best for 'verts?
--------------------------------------------------------------------------------
What is "Best" is a very subjective question - what I think is best may not be the same as what someone else thinks is best.
If the car is going to be a daily-driver, you obviously don't want to go with too high a spring rate - ride quality will suffer at some point. How harsh/stiff a ride you can tolerate is not easily communicated or explained, but most people I have spoken with consider spring rates over 750lb front & 800lb rear to be too stiff/harsh.
The '01 Cobra coupe & convertible came with 500lb front/470lb rear springs from the factory, while the '03 Cobra coupe has 600lb springs front & rear (the '03 'vert still has the 500lb front & 470lb rear setup). The '00 Cobra R had spring rates of 800lb front/750lb rear.
Here is a list of spring rates for comparison:
(Where a range is listed, this indicates a progressive spring rate. A single number denotes a linear spring rate. Values in BOLD are IRS-specific.)
SPRING FRONT REARSPRING FRONT/REAR
1999 Cobra.......................500/470
2000 Cobra "R".................800/750
2001 Cobra.......................500/470
2003 Cobra Coupe............600/600
2003 Cobra Convertible....500/470
H&R, 99-01 cobra w/IRS
(except convertible) 700-760/685
H&R, 99-01 cobra
convertible, Super Sport 700-760/685
H&R, 99-01 cobra
convertible, Race 750-850/770
Stock GT.......................... 400-500/165-265
Stock 94-95 Cobra...........400/160
Stock 96-98 Cobra...........400-505/165-265
Eibach ProKit cpe.1.5"......460-570/200-250
Eibach ProKit vert.1.5"......460-570/170-310
Eibach Sport......................660/260
Eibach Race......................700-850/200-260
FMS "B"........................... 425-530/200-300
FMS "C"........................... 650/200-230
FRPP "R".......................... 700-850/200-260
H&R Sport 1.5"................ 500-575/250-285
H&R Supersport 1.5"........ 700-760/275-300
H&R Race........................ 750/265
H&R Superrace................. 1020/300
Suspension Tech Street......725/230
Suspension Tech Comp..... 850/280
Steeda Sport 1.25"............650/200-250
Steeda Comp/St 1.25".......700-850/250
Steeda Full Comp 1.35".....850-1050/???
Global West 1.0"............... 800/160
Global West Drag 1.0".......680/160
Global West Comp 1.0".....1000/160
Griggs coil-overs................350 to 500+50.175 no TA
Griggs coil-overs................225w TA +
panhard
Dech Speeddrive 1.5"........1000-1200/210-280
Jamex 1.5".........................450-550/170-220
MAC................................600,680,700,
800,925160,170,190,215
Mac progressives...............450-520/200-230
Saleen (Eibach ProKit?)..... 460-570/200-250
Kenny Brown 1.5"............. 650/800
Roush (FRPP "R"?)........... ???/???
