Tyre pressures - help please
Discussion
I'm sure I read a thread recently (can't find it now) which said that pressures should be 22 front & 24 rear. When I got my Griff the pressures were - and still are - 28 & 31. The tech spec section is missing from my owners manual, so I assumed the settings were right until I read the recent thread (yes I know, I'm getting Steve's book - but in the meantime...)
Mine is a 4.0 with 5.0 wheels - SO2 on the front and SO1 on rear. I am far from expert on tyre matters, so before I go and let 5-6 lbs out, am I doing the right thing? Have I damaged the tyres? (I've certainly lost a few fillings)
Many thanks in advance for your help
Mine is a 4.0 with 5.0 wheels - SO2 on the front and SO1 on rear. I am far from expert on tyre matters, so before I go and let 5-6 lbs out, am I doing the right thing? Have I damaged the tyres? (I've certainly lost a few fillings)
Many thanks in advance for your help
I am pretty sure that the recommendation for 22/24 applies to all Griffs. I don't believe that there is anything in the (original) bible about pressures, but that they were in the owners manual.
Having misread a guage (and run on 2.2 and 2.4 bar, I think
) I can tell you that it's just uncomfortably twitchy with over-inflated rubber. Someone described it as "like driving on marbles". But, apart from becoming unstuck from the road and suffering potentially uneven wear on the middle of the tread you shouldn't manage to do any damage.
You will get all sorts of different and personal opinions on what to do with pressures on the track and in the wet/dry - but for everyday use I get even wear and predictable handling on the standard whether wet, dry, hot or cold.
Having misread a guage (and run on 2.2 and 2.4 bar, I think
) I can tell you that it's just uncomfortably twitchy with over-inflated rubber. Someone described it as "like driving on marbles". But, apart from becoming unstuck from the road and suffering potentially uneven wear on the middle of the tread you shouldn't manage to do any damage. You will get all sorts of different and personal opinions on what to do with pressures on the track and in the wet/dry - but for everyday use I get even wear and predictable handling on the standard whether wet, dry, hot or cold.
totally agree, when i bought my griff, it felt twitchy ansd as it had just had new rear tyres, checked pressure, they were at 32psi 
the difference when i went down to 24psi was unbelievable. bought a little digital gauge from halfords and always use that instead of petrol stations. also, when replaced front tyres, rechecked and they were set to 32psi. what is it with tyre fitters?
the difference when i went down to 24psi was unbelievable. bought a little digital gauge from halfords and always use that instead of petrol stations. also, when replaced front tyres, rechecked and they were set to 32psi. what is it with tyre fitters?
I'm sure I read a thread recently (can't find it now) which said that pressures should be 22 front & 24 rear. When I got my Griff the pressures were - and still are - 28 & 31. The tech spec section is missing from my owners manual, so I assumed the settings were right until I read the recent thread (yes I know, I'm getting Steve's book - but in the meantime...)
Mine is a 4.0 with 5.0 wheels - SO2 on the front and SO1 on rear. I am far from expert on tyre matters, so before I go and let 5-6 lbs out, am I doing the right thing? Have I damaged the tyres? (I've certainly lost a few fillings)
Many thanks in advance for your help
I suggest you should lower them to sensible figures - 22/24 sound about right. From memory the 'do not exceed' pressure is in the high thirties so unlikely you have done any damage.
jodypress said: .... also, when replaced front tyres, rechecked and they were set to 32psi. what is it with tyre fitters?
The tyre people I use, good though they otherwise are, always insist on 32 psi for everything, too. Next time I think I'll insert the pressure hose up their
and see what they think of 32 psi then 
zippy500 said: My tyre chap asked what pressure I would like I said 24 pi please and he promptly still filled both to over 30 psi. His thoughts were in the right place I suppose.
I'm pretty sure they have to put a high pressure in to make sure the tyre is sitting correctly on the bead. They then either don't bother or forget to reduce it to the normal pressure. After all we owners check tyre pressures at least weekly - don't we lads
Paul
I reckon 22 - 24 is a bit high for SO3's. Stiffer side walls for heavier cars mean the tyres have more intinsic strength, so on my third set of 03's I'm now on 20 - 22.
first sets wore out in the middle on the back (whilst on 22/24).
lots of track days, feels fine, will have to see about wear rates. these are road pressures set warm buy my own guage.
IMHO
...steve
>> Edited by Guillotine on Saturday 1st March 17:31
first sets wore out in the middle on the back (whilst on 22/24).
lots of track days, feels fine, will have to see about wear rates. these are road pressures set warm buy my own guage.
IMHO
...steve
>> Edited by Guillotine on Saturday 1st March 17:31
22/24 is what TVR put in the manual. However, if the car is left standing in the garage whilst all the horrible salt is on the roads, it may pay to inflate them to around 35psi to help prevent flat-spots and remember to deflate them again when you use the car. I roll my car to a different position in the garage about once a week, so that the car does not sit on one section of tyre for weeks at a time.
>> Edited by Toffer on Sunday 2nd March 12:55
>> Edited by Toffer on Sunday 2nd March 12:55
Read with interest Guillotine's comment re stiffer side walls.
Have SO3s on front and back of griff 500, running 22 and 24 front and back.
I also have heavy wear in middle (approx half of area)but not at edges (2 x quarter area).
Suspected this is due to over inflation, but always as hand book says at 24.
Are SO3s stiffer in the side wall than SO2s? Will running backs at 22 instead of 24 make any difference to grip and handling?
For reference, the backs have lasted 3 years and 16k miles, mostly fun miles rather than long journeys, no track days bar a few good wheelspins (and probably left about 500 miles worth of rubber on pit straight!) at Rockingham on drivers parade at Days of Thunder.
No compaints about longevity really, just miffed that if the centre section had not worn, would have lasted to 20k miles.
Graham
Have SO3s on front and back of griff 500, running 22 and 24 front and back.
I also have heavy wear in middle (approx half of area)but not at edges (2 x quarter area).
Suspected this is due to over inflation, but always as hand book says at 24.
Are SO3s stiffer in the side wall than SO2s? Will running backs at 22 instead of 24 make any difference to grip and handling?
For reference, the backs have lasted 3 years and 16k miles, mostly fun miles rather than long journeys, no track days bar a few good wheelspins (and probably left about 500 miles worth of rubber on pit straight!) at Rockingham on drivers parade at Days of Thunder.
No compaints about longevity really, just miffed that if the centre section had not worn, would have lasted to 20k miles.
Graham
I run the s03 about 2 lbs less than So2s. Just takes the harshness away. Try it and see.
Steve
www.tvrbooks.co.uk
Steve
www.tvrbooks.co.uk
At least 2PSI lower for SO3s.
When driving in Italy in the summer I ended up going as low as 17PSI in the end. Took it easy till the tyres were warmed up but found this to be the best starting pressure.
Also when doing a track day check your tyre pressures as regularly as possible. You'll get loads more heat in them on a track day and the pressures will increase significantly.
I have found that on the Griff every 1PSI makes a noticable difference. I change my pressures to suit the condions.
Usually run rear at 21PSI and front at 22.
Feels right for what I want.
Edited to add: thought I'd make an effort since its an FAQ and its a Friday!
www.dustyc-books.co.uk
>> Edited by DustyC on Friday 29th April 11:17
When driving in Italy in the summer I ended up going as low as 17PSI in the end. Took it easy till the tyres were warmed up but found this to be the best starting pressure.
Also when doing a track day check your tyre pressures as regularly as possible. You'll get loads more heat in them on a track day and the pressures will increase significantly.
I have found that on the Griff every 1PSI makes a noticable difference. I change my pressures to suit the condions.
Usually run rear at 21PSI and front at 22.
Feels right for what I want.
Edited to add: thought I'd make an effort since its an FAQ and its a Friday!
www.dustyc-books.co.uk
>> Edited by DustyC on Friday 29th April 11:17
Thanks for that Steve and Dusty - no one mentioned difference between So2s and SO3s, I could well have got another 4-5k out of my rears had I known this before.
Still, I think I've done ok with those considering I was told I might stretch 12k out of the backs if I drove gently when I bought the car 4 years ago (and I don't - tend to enjoy it as it should be) - I believe some folks get as little as 7k out of theirs.
How is the griff Dusty, you've had that just over a year now I'd guess - still grinning?
Graham
Still, I think I've done ok with those considering I was told I might stretch 12k out of the backs if I drove gently when I bought the car 4 years ago (and I don't - tend to enjoy it as it should be) - I believe some folks get as little as 7k out of theirs.
How is the griff Dusty, you've had that just over a year now I'd guess - still grinning?
Graham
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