GDB (04-07) WRX/STI - Tanabe GF210 Springs - NEW

[LaszloT]

I'm considering these Tanabe GF210 springs on a private sale. Part number is GDBGK, reportedly these are JDM spec Tanabe so I can't find much independent info about them.

The seller says these springs (GDBGK) and the TG092 have spring rates of 240lbs/in up Front, and 224lbs/in Rear, and that they lower the WRX approximately 1" front and 3/4" rear.

A healthy increase in rates for WRX but not overly stiff like the TGF107 which the seller suggests I won't likely need a strut upgrade as well right away.

I like that they are spec-C spring rates, but will they be suitable for my stock struts, or should I only install them with upgraded struts like the KYB - Excel-G items?

Will this amount of lowering negatively affect the suspension geometry?

[STeveD]

Swift spec R. Do it once, do it right. http://www.swiftsprings.com/products/sport-compact/spec-r.html

Fresh dampeners are always a good idea. There's a big difference in feel and confidence between Walter's GR with ~100k on the original struts and Trevor's with ~280k.

[LaszloT]

I hear you. The Spec-Rs seem too much spring for an Excel-G strut though.

Wouldn't I need to use an KYB AGX adjustable strut or Koni inserts for that much spring?

[STeveD]

I hear you. The Spec-Rs seem too much spring for an Excel-G strut though.

Wouldn't I need to use an KYB AGX adjustable strut or Koni inserts for that much spring?


Built for track duty, Swift Spec-R springs are designed at the upper limits of the OEM shock valving

Not according to Swift, but you would need 5x100 STi equivalent shock bodies.

The Tanabe's aren't a bad front to rear ratio if you are sure that's what they are, but the SPEC R's don't lower quite as much.

[wparsons]

Does swift sell sport springs for your car Laz? That's what I have and the rates are stock shock (for me at least) friendlier. Some guys are running Spec R's on stock shocks, but they probably won't get quite as much life out of the shocks.

That said, most shock manufacturers suggest replacing shocks around 80-100k km's, so you're probably due anyway.

[LaszloT]

Yes, Swift sells Sport and Spec-R for the '04-'07 WRX.

2004-2007 Subaru Impreza WRX Sedan Sport Spring Specs:
Front Spring Rate – 190 lbs/inch
Rear Spring Rate – 84-151 lbs/inch
Front Drop – 1.0″
Rear Drop – 0.8″

The Spec-R springs have less drop at 20 mm fr/15mm r - and I agree the reduced drop is better - but I'm concerned they are too much spring for my daily driver. The Swift Sport don't seem to be enough spring to switch from the stock WRX.

Spec-R springs and these Tanabe GF210 springs would need an STi-strength strut or better.

[STeveD]

Stock '04 WRX Rear/Front spring ratio = 119/163 = 73%
Stock '04 STi Rear/Front spring ratio = 195/224 = 87%
Tanabe Rear/Front spring ratio = 224/240 = 93%
Swift Spec R Rear/Front spring ratio = 275/285 = 97%
Swift Sport Rear/Front spring ratio = 151/190 = 80%
Steve's STi Rear/Front spring ratio 2014 = 14/12 = 116%
Steve's STi Rear/Front spring ratio 2015 = 11/10 = 110%

For handling balance improvement (less understeer), get the Tanabe or Spec R.

[LaszloT]

Great summary and perspective, STeveD! I love it. :)

Why might you have more rear spring than front on your racing STi though? Isn't the front still a little heavier than the rear?

[STeveD]

Great summary and perspective, STeveD! I love it. :)

Why might you have more rear spring than front on your racing STi though? Isn't the front still a little heavier than the rear?

It's not all about weight bearing. It works to improve balance. Softer front and stiffer rear helps reduce understeer. Not the way Moton, JRZ or MCS spec the spring rates, but I can't deny that it works.


https://youtu.be/JtemkJ-5aXs?t=44s

[LaszloT]

Breathe it. Live it.

Find your place at PLACE2RACE.CA

So enticing. :)

[wparsons]

Plus, spring rate != wheel rate. You have to take into account the motion ratios as well. On my car the front is about 0.95, and the rear is about 0.75. That means much stiffer springs in the rear just to get the same wheel rate (my stock rates are 129F/213R, my swift sport are 168F/252R, the Spec R's are 245F/296R).

I *think* the 04-07 has roughly equal motion ratios front/rear, so then it's just about shifting handling balance like Steve said.