997.1 GT3 Spring Rates

[v8ksn]

Afternoon all

Does anyone know the spring rate of the 997.1 vanilla GT3 please?

I cant for the life of me find them anywhere on the 'net.

Thanks in advance

[isaldiri]

I believe they are

front 40N/mm (same part number as the 996.2 gt3 iirc)
rear 105N/mm

[v8ksn]

isaldiri said:

I believe they are

front 40N/mm (same part number as the 996.2 gt3 iirc)
rear 105N/mm

Excellent, thank you Sir

[Steve Rance]

What are you looking to do?

[v8ksn]

Steve Rance said:

What are you looking to do?

Just exploring Steve. Trying to find a balance that I like between compliance and feedback.

I am currently running 60Nm and 120Nm springs on Ohlins dampers, and was curious as to what the standard spring rates are.

This is for a purely road-use car which I know is 'good enough' fresh out the box with PASM but I like to fiddle and tweak

[Porsche911R]

v8ksn said:

Just exploring Steve. Trying to find a balance that I like between compliance and feedback.

I am currently running 60Nm and 120Nm springs on Ohlins dampers, and was curious as to what the standard spring rates are.

This is for a purely road-use car which I know is 'good enough' fresh out the box with PASM but I like to fiddle and tweak

Fit a short final drive and let me know what it's like :-)

[Steve Rance]

I'd go for a soft assistor spring set up. We went that way on the 996RS and it was perfect

[isaldiri]

v8ksn said:

Just exploring Steve. Trying to find a balance that I like between compliance and feedback.

I am currently running 60Nm and 120Nm springs on Ohlins dampers, and was curious as to what the standard spring rates are.

This is for a purely road-use car which I know is 'good enough' fresh out the box with PASM but I like to fiddle and tweak

Worth considering that the oem spring is iirc a progressive spring while your current (higher rate) spring might well be a linear rate one so especially on the road the difference might be even more than the upfront rate difference.

[EGTE]

There was a recent 911&PW article (actually, several, about one of their 996 C2s, I think) about spring rates on Ohlins. The guy wanted a good B-road blaster, but Center Gravity's gurus really felt the spring rates were too high.

Can't remember the exact punchline, other than they ended up running something like 40 front/60 rear (ie. half or less as stiff as Ohlins default).

A.N.Other really good makes of suspension run 35/70 for road use on 996/997, for info.

[Digga]

EGTE said:

There was a recent 911&PW article (actually, several, about one of their 996 C2s, I think) about spring rates on Ohlins. The guy wanted a good B-road blaster, but Center Gravity's gurus really felt the spring rates were too high.

Can't remember the exact punchline, other than they ended up running something like 40 front/60 rear (ie. half or less as stiff as Ohlins default).

A.N.Other really good makes of suspension run 35/70 for road use on 996/997, for info.

I remember that Ohlins/CG story too, but can't think where from.

[Porsche911R]

Digga said:

I remember that Ohlins/CG story too, but can't think where from.

most after market cars I have been in have too hard spring rates ! KW are always mega hard

I looked for my R but all were double, I just want adjustment not harder rates !

[TDT]

Porsche have increased spring rates on the most recently released GT cars......

[v8ksn]

EGTE said:

There was a recent 911&PW article (actually, several, about one of their 996 C2s, I think) about spring rates on Ohlins. The guy wanted a good B-road blaster, but Center Gravity's gurus really felt the spring rates were too high.

Can't remember the exact punchline, other than they ended up running something like 40 front/60 rear (ie. half or less as stiff as Ohlins default).

A.N.Other really good makes of suspension run 35/70 for road use on 996/997, for info.

I would be really interested in reading that article. Can you remember what was on the front cover? I'll try and buy a digital back issue version.

Chris F set my car up on these Ohlins. He knows what he's doing for sure.

The ride is pretty perfect for fast A and B roads. It now flows with the road as opposed to fighting it but its too soft for track work. I can set the dampers to fully stiff but then its a little skittish.

Its a compromised set up for road AND track, but its brilliant on the road.

[TDT]

[TDT]

Followed up by this one with all the spring rate detail work @ CG.

[v8ksn]

You absolute legend! Thank you

[Slippydiff]

Ohlins are fast gaining a reputation for specifying spring rates that are waaaay too stiff for British roads (and that’s about as straight from the horses mouth as you can get...)
FWIW, when I had the ex-996 GT3 R/RSR 3 way adjustables rebuilt for road-only use on my Mk 1 996 GT3, I went with 70n/m rears and 35n/m fronts (standard 28n/m front, rears 60 or possibly 65n/m)
Rear is firm but compliant, fronts slightly more compliant, but the damping is several leagues above that offered by the R&T’s, thus you can wind up the compression a couple of clicks without the damping becoming harsh, or back them off without the car becoming soggy.

As Isaldiri said, the spring rates don’t really mean a lot when applied to a variable rate spring. I bought a new set of fronts and rears to enable my damper guy to dyno them to work out as best he could what the rates were once the soft coils had been compressed or become coilbound.

Edited by Slippydiff on Thursday 10th May 22:36

[isaldiri]

Steve Rance said:

I'd go for a soft assistor spring set up. We went that way on the 996RS and it was perfect

Is there a noticeable variance in handling as one spring becomes fully blocked? I've always wondered what the transition between between the 2 very different springs would be like and whether that can be smooth/seamlessly done.

[v8ksn]

Slippydiff said:

Ohlins are fast gaining a reputation for specifying spring rates that are waaaay too stiff for British roads..

Yep! Chris agrees with you. Ohlins recommended 90Nm front and 140Nm rear. Chris said these would be way too stiff for my desired set up so recommended the 60Nm and 120Nm rates. These are perfect for my for road use but obviously way too soft for track.

[Digga]

v8ksn said:

The ride is pretty perfect for fast A and B roads. It now flows with the road as opposed to fighting it but its too soft for track work. I can set the dampers to fully stiff but then its a little skittish.

You generally find with dampers that there's only a small amount of actual, usable adjustment within the 'theoretical' number of clicks/settings. Too much damping with too low a spring rate and the car sits of the damper, not the spring which, as you say, does not work!

Slippydiff said:

Ohlins are fast gaining a reputation for specifying spring rates that are waaaay too stiff for British roads (and that’s about as straight from the horses mouth as you can get...)

It's not just Ohlins and it's not just with cars. I ride mtb with a bunch of guys. We're all pretty handy, can tackle an Alpine downhill course on our day and descend pretty rapidly. (Four of us running line astern set a Strava record on a descent, in the dark last night). No matter what size and weight of rider and no matter which make of fork, we all run far lower air pressure (effective spring pressure) than suggested manufacturer's settings. We probably run a fair bit faster rebound than stock spec too.

I don't know why this is. Bike suspension firms (Fox, Rock Shox, Ohlins, X-Fusion, Marzocchi etc.), like car suspension firms (and one is very often involved in the other of course) clearly spend huge amounts of R&D on settings - when I was riding in Verbier last summer, I noticed Ohlins had a permanent base at the bike park there - but still don't always come up with the right answers.