Spring rates for Nitrons ....
Discussion
Johno, out of interest what are the 'standard' spring rates for the girff 
. I would have thought your experience with the S would have put you in the right ball park of where you'd want to go with the griff though.
Hows the motor going, last time I saw it it was laid up in a garage awaiting 'some' work.
harry
. I would have thought your experience with the S would have put you in the right ball park of where you'd want to go with the griff though. Hows the motor going, last time I saw it it was laid up in a garage awaiting 'some' work.
harry
I have a vague recollection that it's 280lb front and 320lb rear. They're variable rate (or whatever) so these would be the max rate.
There was a Sprint article some while ago where rates of c. 600lb were being used I think but that was very much track biased. I think Nitron used to supply a 12.5% upgraded spring with their shocks.
Most likey will be upgrading the shocks next year so interested to hear other's opinions.
There was a Sprint article some while ago where rates of c. 600lb were being used I think but that was very much track biased. I think Nitron used to supply a 12.5% upgraded spring with their shocks.
Most likey will be upgrading the shocks next year so interested to hear other's opinions.
GreenV8S said:
That's relatively soft at the front isn't it? Do you have a rear ARB?
Another V8S chipping, I thought that sound a bit soft too. I assume by the apparent rear bias tot he spring rates they either have rear arb or the spring seat angle (effective wheel rate) is significantly differnet from the V8S.
Harry
Not helping the grif owners though, interesting non-the-less
.Standard settings - and all the settings I've tried - were stiffer at the front than at the rear.
The 'standard' (and there were, as you would expect with TVR) variations for the Griff 500 was 325 front and about 200 ish at the rear.
I'm currently running 400 F, 325 R and I think Johno, that the 'touring' bit of your requirements would be unpleasant with any more than this. There are cars running over 800 lb springs, but they only really work on flat, smooth, fast circuits.
Springs don't need to cost much, so as Pete says, you can buy a few sets, or do as Pete suggests and change things incrementally. Big changes in rate may require a Nitron re-tune of the valving.
The 'standard' (and there were, as you would expect with TVR) variations for the Griff 500 was 325 front and about 200 ish at the rear.
I'm currently running 400 F, 325 R and I think Johno, that the 'touring' bit of your requirements would be unpleasant with any more than this. There are cars running over 800 lb springs, but they only really work on flat, smooth, fast circuits.
Springs don't need to cost much, so as Pete says, you can buy a few sets, or do as Pete suggests and change things incrementally. Big changes in rate may require a Nitron re-tune of the valving.
On the S I was running 400 fronts and 350 rears ... The springs were fine and the ride would have been much better if the dampers had been up to it ...
My understanding was that as standard (and confirmed below) was 280lb rear and 300 lbs front.
I have a friend who ran 700lbs front and 500lbs rear on his S very successfully in the sprinting field. You know him Pete !
The ride on the car for normal road use was very good. But too harsh for the Griffith.
A 12.5% increase would give only 315lbs and 360lbs.
My experience has been that the better the quality of the damping the harder the spring rate can be without detriment to the ride quality.
Digga, your spring rates sound about right to me ..
Guillotine, are you sure that your spring rates are harder at the rear and softer at the front ???
My basic school boy maths says that the standard rears are 87.5% of the fronts and therefore to enhance them in line with the orginal would lead to a 350lbs rear and 400lbs front.
325lbs rear is too soft with according to the maths, but that does in no way take account of dampers, car set up and driver preference.
This also doesn't take account of it being a rising rate soring either and this is what leads to the initial 'barge' like action of my beloved Griffith on track ...
My understanding was that as standard (and confirmed below) was 280lb rear and 300 lbs front.
I have a friend who ran 700lbs front and 500lbs rear on his S very successfully in the sprinting field. You know him Pete !
The ride on the car for normal road use was very good. But too harsh for the Griffith.
A 12.5% increase would give only 315lbs and 360lbs.
My experience has been that the better the quality of the damping the harder the spring rate can be without detriment to the ride quality.
Digga, your spring rates sound about right to me ..
Guillotine, are you sure that your spring rates are harder at the rear and softer at the front ???
My basic school boy maths says that the standard rears are 87.5% of the fronts and therefore to enhance them in line with the orginal would lead to a 350lbs rear and 400lbs front.
325lbs rear is too soft with according to the maths, but that does in no way take account of dampers, car set up and driver preference.
This also doesn't take account of it being a rising rate soring either and this is what leads to the initial 'barge' like action of my beloved Griffith on track ...
HarryW said:
Johno,
in a garage awaiting 'some' work.
harry
Indeed .... still there, but there is progress .... that progress will result in the necessity for the new dampers
... The old are knackered anyway and were due a change, but I might aswell do the whole lot at once. Should see it back in time for Touring in Scotland at the end of July/August !!
Drop me a mail and I will expand.
johno said:
Johno,
in a garage awaiting 'some' work.
harry
Indeed .... still there, but there is progress .... that progress will result in the necessity for the new dampers
Should see it back in time for Touring in Scotland at the end of July/August !!
Drop me a mail and I will expand.
I'll see it again next Thursday when I'm back there for some more fettling with MA
. I'll get the low down from Mike or Paul whilst there. You must be missing it though it seems an age to me and its not even my car
. Forgot to mention last I was there, who stole your LE badge
harry
HarryW said:
the spring seat angle (effective wheel rate) is significantly differnet from the V8S.
Harry
Yes, you're right. In a nutshell, it's not wise to compare spring rates between different chassis, as the angle of installation/loading of the spring and shocks varies, and hence also the required poundage of the springs too.
I'd still have thought it normal to have stiffer fronts than rears...
I've just tried to find the article that stated the original spring rates - but can't find it 
I did find an article on the purple Chimeara "V8 NUT" which mentioned upgraded springs of 400lb front and 300lb rear.
Although it seems all wrong, my recollection is that the rears are higher rate than the front.
I did find an article on the purple Chimeara "V8 NUT" which mentioned upgraded springs of 400lb front and 300lb rear.
Although it seems all wrong, my recollection is that the rears are higher rate than the front.
You can't compare spring rates between different cars unless they have the same suspension geometry, but if they have similar roll centers then you can use wheel rates as a good starting point. From what I can remember the Griffith wishbone geometry is similar front and rear and also similar to the S front wishbones. So I expect you'll find the relationship between the spring rate and the wheel rate is similar i.e. about 2:1.
Conventionally, for a comfortable ride the bump rates are normally set with a pitch rate moment ratio of 1.6 - in simple terms the rear about 60% stiffer than the front. BUT, to control the yaw balance of the car you also need to control how much lateral weight transfer happens at the front of the car and how much at the rear. This is determined by the roll centers (which are relatively fixed) and the roll stiffness at each end of the car. The roll stiffness comes from the road springs and any anti-roll bars that are fitted. For a powerful rear wheel drive car you would normally want the rear roll stiffness a lot softer (roughly 50%) of the front roll stiffness. Hence my question about the rear anti-roll bar. If you have a very stiff bar on the front and none on the back, you might be able to get away with softer springs at the front. I don't think that the standard front arb is that stiff though, and even if you don't have any arb at all at the back I think the rear will have too much roll stiffness with those springs. If you have an arb at the back too, it seems even less likely that the balance will be anywhere near neutral with those stiff springs at the back.
Of course, if the wishbone geometry is different from the way I remember it then it could be these springs will give a softer rear wheel rate than I predict, in which case it might work OK after all.
Conventionally, for a comfortable ride the bump rates are normally set with a pitch rate moment ratio of 1.6 - in simple terms the rear about 60% stiffer than the front. BUT, to control the yaw balance of the car you also need to control how much lateral weight transfer happens at the front of the car and how much at the rear. This is determined by the roll centers (which are relatively fixed) and the roll stiffness at each end of the car. The roll stiffness comes from the road springs and any anti-roll bars that are fitted. For a powerful rear wheel drive car you would normally want the rear roll stiffness a lot softer (roughly 50%) of the front roll stiffness. Hence my question about the rear anti-roll bar. If you have a very stiff bar on the front and none on the back, you might be able to get away with softer springs at the front. I don't think that the standard front arb is that stiff though, and even if you don't have any arb at all at the back I think the rear will have too much roll stiffness with those springs. If you have an arb at the back too, it seems even less likely that the balance will be anywhere near neutral with those stiff springs at the back.
Of course, if the wishbone geometry is different from the way I remember it then it could be these springs will give a softer rear wheel rate than I predict, in which case it might work OK after all.
Gassing Station | Griffith | Top of Page | What's New | My Stuff