Tyre Pressures
Discussion
I currently have 245/45 x 16 and 225/45 x 16 Toyo Proxes T1R fitted to my 500 with PAS. The previous owner had changed from 15" to 16" fronts to improve tyre choice.
The handbook recommends 22psi front, 24psi rear which is what I have been using of late. On buying the car, I found that they were set much softer - say 18 and 20 respectively.
Personally, I found the softer setting better but was concerned about abnormal tyre wear hence the change to the recommended figures.
Do wonder whether I should set the fronts softer as presumably the 22 psi figure is for the "standard" 225/50 x 15s "normally" fitted to 500s with PAS.
Any comments/advice much appreciated.
Thanks,
Jim
The handbook recommends 22psi front, 24psi rear which is what I have been using of late. On buying the car, I found that they were set much softer - say 18 and 20 respectively.
Personally, I found the softer setting better but was concerned about abnormal tyre wear hence the change to the recommended figures.
Do wonder whether I should set the fronts softer as presumably the 22 psi figure is for the "standard" 225/50 x 15s "normally" fitted to 500s with PAS.
Any comments/advice much appreciated.
Thanks,
Jim
I run mine on 22/24 psi with 17 inch wheels. Some prefer 24/26. All TVRs are similar. Just adjust a couple of pounds up or down to get them to what feels right to you. Remember that if you are running a medium sized daily driver on similar sized tyres at 30 psi you are carrying 1.8 tonnes rather than the TVR's 1.1 tonnes.
The previous owner might not have checked his pressures recently - I checked my fronts yesterday for the first time in 4weeks and they were 20.5 psi.
Also, on track days I have to let air out after half an hour - my 22/24 psi have morphed into 27/29. Spirited driving will achieve 25/27 from a cold base of 22/24.
The previous owner might not have checked his pressures recently - I checked my fronts yesterday for the first time in 4weeks and they were 20.5 psi.
Also, on track days I have to let air out after half an hour - my 22/24 psi have morphed into 27/29. Spirited driving will achieve 25/27 from a cold base of 22/24.
Anthony(Qbee), your looking for 29 to 31 psi after a track session, soon as you come off the track, take the caps off before you go out. If your pressures are below that after a session there not really upto temp!
We made a mistake with the Mazda car and set the pressures when wheels were warm to 24psi, forgot to check them the following day when stone cold, after a race the tyres were only 28 psi, not enough to get the tyres sticky and it buggered up the outside edge as well as being slower by some 2 secs a lap!
As for tyre pressures on the road, 22/24 works well for me, the roads are rough so helps to increase the heat so hence the pressures as they warm up.
My simple rule of thumb is to put my hand on the tyre after a run and it needs to feel pretty hot, if not the tyre isn't really grabbing the surface when cornering.
Rather vague but it's always a good idea to experiment and the hand test is very simple.
I've used a temp gauge on the tyres quite a lot now and 30 degrees does feel fairly hot on the hand,,,,, if that helps.
We made a mistake with the Mazda car and set the pressures when wheels were warm to 24psi, forgot to check them the following day when stone cold, after a race the tyres were only 28 psi, not enough to get the tyres sticky and it buggered up the outside edge as well as being slower by some 2 secs a lap!
As for tyre pressures on the road, 22/24 works well for me, the roads are rough so helps to increase the heat so hence the pressures as they warm up.
My simple rule of thumb is to put my hand on the tyre after a run and it needs to feel pretty hot, if not the tyre isn't really grabbing the surface when cornering.
Rather vague but it's always a good idea to experiment and the hand test is very simple.
I've used a temp gauge on the tyres quite a lot now and 30 degrees does feel fairly hot on the hand,,,,, if that helps.
Edited by ClassiChimi on Wednesday 30th July 20:48
Anthony(Qbee), your looking for 29 to 31 psi after a track session, soon as you come off the track, take the caps off before you go out. If your pressures are below that after a session there not really upto temp!
We made a mistake with the Mazda car and set the pressures when wheels were warm to 24psi, forgot to check them the following day when stone cold, after a race the tyres were only 28 psi, not enough to get the tyres sticky and it buggered up the outside edge as well as being slower by some 2 secs a lap!
As for tyre pressures on the road, 22/24 works well for me, the roads are rough so helps to increase the heat so hence the pressures as they warm up.
My simple rule of thumb is to put my hand on the tyre after a run and it needs to feel pretty hot, if not the tyre isn't really grabbing the surface when cornering.
Rather vague but it's always a good idea to experiment and the hand test is very simple.
I've used a temp gauge on the tyres quite a lot now and 30 degrees does feel fairly hot on the hand,,,,, if that helps.
We made a mistake with the Mazda car and set the pressures when wheels were warm to 24psi, forgot to check them the following day when stone cold, after a race the tyres were only 28 psi, not enough to get the tyres sticky and it buggered up the outside edge as well as being slower by some 2 secs a lap!
As for tyre pressures on the road, 22/24 works well for me, the roads are rough so helps to increase the heat so hence the pressures as they warm up.
My simple rule of thumb is to put my hand on the tyre after a run and it needs to feel pretty hot, if not the tyre isn't really grabbing the surface when cornering.
Rather vague but it's always a good idea to experiment and the hand test is very simple.
I've used a temp gauge on the tyres quite a lot now and 30 degrees does feel fairly hot on the hand,,,,, if that helps.
Edited by ClassiChimi on Wednesday 30th July 20:50
For the road I'd say a low ish pressure to encourage some heat but then it depends on how hard your gonna be driving and what the road temps are?
If your driving fast I'd go harder so as to not get to much tyre roll, the extra air gets hot and penetrates through the tyre and gives even more heat/ grip,,,, but go over the top and you'll just be too hard and have less grip etc,
So there's a number of factors determining what's best at what times, if you go harder remember you'll have a lot less grip until it's all hot.
So if you put your hand on the tyre and it hurts it's probably to hot, if its Luke warm the tyre ain't working enough, road use it's about high speed straights and very slow corners so less air will give some friction and heat so helping cornering but not neccessarily!!!???
It goes on like that?!!?!!
If your driving fast I'd go harder so as to not get to much tyre roll, the extra air gets hot and penetrates through the tyre and gives even more heat/ grip,,,, but go over the top and you'll just be too hard and have less grip etc,
So there's a number of factors determining what's best at what times, if you go harder remember you'll have a lot less grip until it's all hot.
So if you put your hand on the tyre and it hurts it's probably to hot, if its Luke warm the tyre ain't working enough, road use it's about high speed straights and very slow corners so less air will give some friction and heat so helping cornering but not neccessarily!!!???
It goes on like that?!!?!!
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