tyre pressures
Discussion
Now it's interesting you should say that Jensena coz I upped the pressures for an expected high-speed sesh recently and the rear was all over the place on long high-speed curves. I've got Toyos fitted and since returning to standard pressures again, she has returned to the solid, confidence-inspiring surefootedness she had before.
Edited by Mr.Cerbera on Thursday 10th August 01:24
I was just quoting from the manual - unfortunately I live in England where it's impossible to do any 'Sustained High speed driving' 
Also I believe the tyre and wheel size is irrelevant to the pressure - i.e a TVR Cerbera needs 22/24 psi regardless of the size of the tyres. If you think about it no matter size tyre you have , 22psi is 22 psi.
Also I believe the tyre and wheel size is irrelevant to the pressure - i.e a TVR Cerbera needs 22/24 psi regardless of the size of the tyres. If you think about it no matter size tyre you have , 22psi is 22 psi.
Yes and no.
Tyres with a larger footprint e.g. those that are running wider wheels etc technically should be running a lower pressure to keep the pressure distribution the same.
However, larger footprint tends to go with larger diameter wheels and also lower profile tyres. Which really need a little bit more pressure to prevent side wall deflection and the following wheel damage.
If I knew I was going to be on smooth roads thoughpout my drive I'd run approx 24 psi in mine. I tend to keep them up at 28psi at the mo though as the wheels would take a beating otherwise.
Protechs, 4.5, 255/35-19 fronts and 275/35-19 rears.
Not bouncy on that set up either.
Tyres with a larger footprint e.g. those that are running wider wheels etc technically should be running a lower pressure to keep the pressure distribution the same.
However, larger footprint tends to go with larger diameter wheels and also lower profile tyres. Which really need a little bit more pressure to prevent side wall deflection and the following wheel damage.
If I knew I was going to be on smooth roads thoughpout my drive I'd run approx 24 psi in mine. I tend to keep them up at 28psi at the mo though as the wheels would take a beating otherwise.
Protechs, 4.5, 255/35-19 fronts and 275/35-19 rears.
Not bouncy on that set up either.
Well I think your wrong Ridds I'm still sticking with my theory that 22psi=22psi no matter what size tyre, because the size is irrelevant, 1 pound per square inch is 1 pound per square inch. Tyre pressures are determined by the weight of the car, no matter how big a tyre you fit, you still need it to be 22psi ! The colume of air you put into a bigger tyre will increase, but the pressure per square inch always needs to be the same.
If you look at the TVR recomeneded pressures for the 4.2, with 16" wheels and 225/45 front and 245/45 rear, they are exactly the same presuures as those recomended for the 17" wheels of the 4.5.
And guess what? The Speed 6 with 225/50x16 front and rear, also have EXACTLY the same pressures.
So for all 3 cars, all with totally different tyre sizes, the pressures are all the same, 22psi front and 24 psi rear.
Oh this is fun !
I'm still sticking with my theory that 22psi=22psi no matter what size tyre, because the size is irrelevant, 1 pound per square inch is 1 pound per square inch. Tyre pressures are determined by the weight of the car, no matter how big a tyre you fit, you still need it to be 22psi ! The colume of air you put into a bigger tyre will increase, but the pressure per square inch always needs to be the same. If you look at the TVR recomeneded pressures for the 4.2, with 16" wheels and 225/45 front and 245/45 rear, they are exactly the same presuures as those recomended for the 17" wheels of the 4.5.
And guess what? The Speed 6 with 225/50x16 front and rear, also have EXACTLY the same pressures.
So for all 3 cars, all with totally different tyre sizes, the pressures are all the same, 22psi front and 24 psi rear.
Oh this is fun !
True, kinda right and kinda wrong. :lol
Pressure should never really be lower than stated in the handbook although I do stand by the upping the pressure to protect the sidewall etc.
Pressure should be calcualted from vehicle weight and load index of the tyre compared to that of the tyres previously fitted.
Pressure should never really be lower than stated in the handbook although I do stand by the upping the pressure to protect the sidewall etc.
Pressure should be calcualted from vehicle weight and load index of the tyre compared to that of the tyres previously fitted.
I would have thought (and I do no nothing on the subject) that to have a lower pressure on a higher profile tyre will mean the sidewall will 'flex' abit more therefore giving a very wallowey ride.
And although true about the possibility of damaging the wheels with a lower profile tyre with low pressure, if your going to hit a pothole that big, then your either travelling too fast or not watching the road surface.
And although true about the possibility of damaging the wheels with a lower profile tyre with low pressure, if your going to hit a pothole that big, then your either travelling too fast or not watching the road surface.
Interesting.......
I used to run 26psi fronts and 28 psi rear, but now.....
I run 26psi front and 24psi rear on 18" Spiders on Protechs.
At the Pod I run 45psi front and 15psi rear
I am currently running Falken FK452 225/35/18 front (better side wall fit than the Toyos) and Bridgestone S02 255/35/18 on the rear.
I doubt it's really that critical, but more of a personal choice as to what feels right for you.
Jules.
I used to run 26psi fronts and 28 psi rear, but now.....
I run 26psi front and 24psi rear on 18" Spiders on Protechs.
At the Pod I run 45psi front and 15psi rear
I am currently running Falken FK452 225/35/18 front (better side wall fit than the Toyos) and Bridgestone S02 255/35/18 on the rear.
I doubt it's really that critical, but more of a personal choice as to what feels right for you.
Jules.
Hmmmm, and to throw another stick on the fire.....
Given the physics of car mass over tyre area as a primary factor, aren't manufacturers construction types more relevant to what pressures we should run if we should change from standard fittings. I certainly remember that when I used to change tyres on my bikes, I would always consult Sharples' Tyres oop North for which pressures to use and they almost invariably gave different pressures depending on the make/model of tyre.
Given the physics of car mass over tyre area as a primary factor, aren't manufacturers construction types more relevant to what pressures we should run if we should change from standard fittings. I certainly remember that when I used to change tyres on my bikes, I would always consult Sharples' Tyres oop North for which pressures to use and they almost invariably gave different pressures depending on the make/model of tyre.
Edited by Mr.Cerbera on Wednesday 16th August 03:30
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