MFG's SPRING RATES
 

I was looking at my JIC suspension today and researched a number of competing coilovers and springs. Since I had all of the info in front of me I thought it would be nice to post all the spring rates in one place.

Jeff


STOCK
350Z 347/419

TEIN
Basic 504/504
CS 392/392
Flex 671/671
H-Tech Springs 358/375
S-Tech Springs 386/402

NISMO
S-Tune 448/504

HKS
Hypermax II 616/616
Hypermax LS 560/392

TANABE
Sustec Pro SSII 560/448
NF210 Springs 314/353
GF210 Springs 336/375

JIC-MAGIC
FLT-A2 Linear 560/672
FLT-A2 Prog. 560/560

CUSCO
Zero 1 560/392
Zero 2 560/392

EIBACH
Springs 384/421

Re: MFG's SPRING RATES
 

Jeff, your oem rate info is incorrect. And I'm to blame for that. I posted a correction some time ago, but not everyone saw the post. Here's my mass listing for springs and coilovers, data includes how they differ from oem and where they might transfer roll stiffness. Did you get the Tanabe coilover rates from Tanabe by calling the company?

Can you pm me about your HKS Hypermax II rate data?

Oem springs
Front:314 Rear:342

Eibach's as noted (first number is the softer initial rate, followed by the higher final rate)
350Z 296/384 front 316/421 rear
G35c 229/337 front 274/463 rear
G35s 259/334 front 359/413 rear

RSR 350Z springs (just a wee bit progressive F&R, maybe one coil is progressive)
345/417 F+10% R+22%
Transfers +12% roll stiffness to rear

RSR G35 coupe springs (progressive front and rear)
315/315 F+0 R-8%
Transfers +8% roll stiffness to front

Hotchkis 350Z springs (linear springs)
340/330 F+8% R-3%
Transfers +12% roll stiffness to front

Tein S-tech 350z (fronts are progressive, rears are linear)
386/402 F+23% R+16%
Transfers +7% roll stiffness to front

Tein H-tech 350z (fronts are progressive, rears are linear)
358/375 F+14% R+11%
Transfers +3% roll stiffness to front

Tein H-tech G35 coupe & sedan(fronts are progressive, rears are linear)
324/260 F+ 5% R-22%
Transfers +27% roll stiffness to front

Tein S-tech G35 coupe & sedan (fronts are progressive, rears are linear)
358/274 R+14% R-18%
Transfers +32% roll stiffness to front

Tanabe GF210 Series 350Z
336/375 F+7% R+10%
Transfers +3% roll stiffness to rear

Tanabe NF210 Series 350Z
314/353 F+0 R+3%
Transfers +3% roll stiffness to rear

Tanabe NF210 Springs G35 COUPE
297/336 F-5% R-2%
Transfers +3% roll stiffness to front

Tanabe DF210 Springs G35 COUPE
308/353 F-2% R+3%
Transfers +5% roll stiffness to front

Tanabe NF210 Springs G35 SEDAN
297/269 F-5% R-21%
Transfers 17% roll stiffness to front

Tanabe DF210 Springs G35 SEDAN
286/280 F-9% R-18%
Transfers +9 roll stiffness to rear

Kg/mm springs 350Z
DR21 super sport 15mm drop
246/398 front 252/409 rear

Kg/mm springs 350Z
DRacing 30mm drop
252/454 front 252/482 rear

Espelir coupe springs (the U.S. importer recently changed specs, I do not believe the newly listed specs are correct, since the new one's are extreamly high. And when I called the company to ask if the springs are linear or progressive, they told me Linear, turn's out they were absolutley wrong, they are in fact progressive. I show the old specs for those reasons, take it with a grain of salt, same thing for the 350Z fitment)
409/460F F+30% R+37%
Transfers +7% roll stiffness to rear

Espelir 350Z springs
381/460 F+22% R+37%
Transfers +15% roll stiffness to rear


Tein Flex
672/672 F+114% R+98
Transfers +16% roll stiffness to front

Tein Flex JDM specs (can be special ordered est 6-8 weeks delivery)
560/560 F+78% R+64%
Transfers 14% roll stiffness to front

Tein Basic
504/504 F+61% R+43%
Transfers +18% roll stiffness to front

Tein SS (JDM only at this time. 6-8 weeks delivery, come via ship)
392/314-392 (rear’s are progressive
F+25% R+15% at peak
(differs from CS, twin tube, progressive rear springs, and cost is lower

Tein CS (Monotube)
392/392 F+25% R15%
Transfers +10% roll stiffness to front

Nismo S-tune (uses progressive springs, especially in rear)
350Z/G35 Coupe
448/504 F+43% R+48%
Transfers +5% roll stiffness to rear
Nismo S-tune (uses progressive springs)
G35 Sedan
347/342 F+10% R+0%
Transfers 10% roll stiffness to front

Buddy Club Racing Spec coilover (Monotube)
748/280*
(very likely run's rear springs on the dampner body and not at the oem rear spring location)

Jic Flta-2 350Z fitment (Monotube)
560/672 F+78% R+98%
Transfers +20% roll stiffness to rear

Jic Flta-2 G35 coupe (Monotube)
560/560 F+78% R+64% $1750
Transfers 14% roll stiffness to front

Jic Flta-2 G35 sedan (Monotube)
504/392 F+61% R+15%
Transfers +46% roll stiffness to front

Cusco Zero 1&2
560/392 F+78% R+15%
Transfers +63% roll stiffness to front (no they do not run their rear springs on the dampner body, oem location, seen them on the car with my own eyes.)

HKS LS+ (rear springs are progressive)
496/440 +58%front +29%rear
transfers 29% roll stiffness to the front

HKS LS G35
448/336 43%front -1%
transfers 44% roll stiffness to the front

HKS LS 350z
448/448 43%front +31%
transfers 12% roll stiffness to the front

HKS II 504/504 +61%front +47%rear $1600
transfers 14% roll stiffness to the front

HKS RS 448/448 F+43% R+31%
Transfers 12% roll stiffness to the front
(specifically valved less aggressively then
The II coilover’s)

Zeal function V6 coil over $2855
Both G35 and 350Z rates are the same
560/448 F+78% R+31%
Transfers +47% roll stiffness to front

KW coilovers Variant's 1,2&3
Variant 3's are noteworthy as the only known coilover for these cars where the dampners are adjustable for compression and rebound independently. They also differ in using progressive springs front and rear
Front: 485lbs to 525Lbs Rear: 240Lbs to 548Lbs

D2 Racing Coilovers (Monotube)
840/728 F+168% R+113% (wee bit stiff eh, the recommended rate to)
Transfers 55% roll stiffness to front

GSedan35,

In your transfer of roll stiffness, it looks like you did account for the effective spring rate based on whether the rear spring is located in the OEM position vs a coilover. Am I correct?

With such a huge variation in roll stiffness bias, I can see why it's so hard to choose a suspension setup. Makes me wonder who knows what they're doing, and who doesn't. If these performance parts manufacturers come up with such different setups, how are we supposed to decipher what works and what doesn't without going through our own extensive R&D?

Now that I've complicated my suspension set up with variables that differ from OEM (alignment, tire widths, wheel offsets, sways), buying a spring or coilover set up has become more difficult, as I have no clue what variables these manufacturers used to come up with their spring and dampening rates.

Oh, well, I guess this is the "joy" of tuning.