Tyre Pressures for Track Days
Discussion
Best to start with recommended pressures then stop after few fast laps and check them, alter as required.
Then check again after few more laps and should have settled down to correct and steady pressure / temperature...
Don't forget to stop at garage on way home and pump them back up....
Then check again after few more laps and should have settled down to correct and steady pressure / temperature...
Don't forget to stop at garage on way home and pump them back up....
Dave Sums said:
Best to start with recommended pressures then stop after few fast laps and check them, alter as required.
Then check again after few more laps and should have settled down to correct and steady pressure / temperature...
Don't forget to stop at garage on way home and pump them back up....
how can he alter as required, they will be hotter, he will have no idea what to alter them to once warm :-).Then check again after few more laps and should have settled down to correct and steady pressure / temperature...
Don't forget to stop at garage on way home and pump them back up....
to many factors regarding PSI on track to quote any one a direct figure.
mrdemon said:
how can he alter as required, they will be hotter, he will have no idea what to alter them to once warm :-).
to many factors regarding PSI on track to quote any one a direct figure.
So please give your advice then as I don't wish to give bad info.... what I said worked for me and my tryes offered good grip and didn't get wrecked too quickly..to many factors regarding PSI on track to quote any one a direct figure.
I can't imagine he is going to be ragging a 3.2 around Oulton Park like a GT3 so all I'm saying as tyres get hotter, pressure will go up and all I am suggesting is to reduce that pressure to around recommended figure for that car on those tyres for high speed driving. Once you have checked it a few times it usually become pretty stable unless driving style or weather changes....
hot the tyres will be much higher pressure, so once he has been out if he don't know what the hot should be how can he ajust ?
imo the best thing to do is set all 4 tyres 2 psi less when cold.
with out testing equipment that's about the best one can hope for imo.
I don't know his geo, how hard he drives,if on r spec tyres, how many laps he will do, the track temp etc etc.
the weather is not that warm with loads of rain atm.
imo the best thing to do is set all 4 tyres 2 psi less when cold.
with out testing equipment that's about the best one can hope for imo.
I don't know his geo, how hard he drives,if on r spec tyres, how many laps he will do, the track temp etc etc.
the weather is not that warm with loads of rain atm.
It will be a lot more than 2psi less!
Arrive at circuit with normal pressures.
Do one out lap, one hot lap, come in straight away whilst still hot. Bleed air until you hit normal pressures.
Go out again, two hot laps, come in, bleed more. You should be good by now, but it doesn't hurt to keep checking through.
Don't forget to pump back up before you drive home.
Arrive at circuit with normal pressures.
Do one out lap, one hot lap, come in straight away whilst still hot. Bleed air until you hit normal pressures.
Go out again, two hot laps, come in, bleed more. You should be good by now, but it doesn't hurt to keep checking through.
Don't forget to pump back up before you drive home.
Just buy a Michelin Rapid Tyre Inflator or similar, great piece of kit for the whole family of cars and way portable enough for track days. With one of these you can do up or down adjustments on the day off your own 12v supply!
http://lovetyres.com/p/Tyre-Accessories/Electric-T...
http://lovetyres.com/p/Tyre-Accessories/Electric-T...
Harris_I said:
It will be a lot more than 2psi less!
Arrive at circuit with normal pressures.
Do one out lap, one hot lap, come in straight away whilst still hot. Bleed air until you hit normal pressures.
Go out again, two hot laps, come in, bleed more. You should be good by now, but it doesn't hurt to keep checking through.
Don't forget to pump back up before you drive home.
I find on track days most run too soft a psi when tested :-)Arrive at circuit with normal pressures.
Do one out lap, one hot lap, come in straight away whilst still hot. Bleed air until you hit normal pressures.
Go out again, two hot laps, come in, bleed more. You should be good by now, but it doesn't hurt to keep checking through.
Don't forget to pump back up before you drive home.
on my R-spec race maxx tyre in the colder weather I only have to drop the cold pressure 3psi for track use.
doing laps upon laps and setting your PSI back to the cold pressure will be way to soft.
again some tyres need a bigger change some need a smaller change, no way of guessing it and def not doing a load of laps and setting the psi back to what they should be cold !!!!
doing this will also take you many many laps to get the tyres where they should be when you go back out on track with cold tyres again and again. your 1st few laps will feel crap, this will also kill your tyres and your edges doing lap after lap on cold low PSI road tyres as you will down at 20psi.
Again some people only stay out 5 or 6 laps, some stay out 20+ laps, I am the former and only do about 6 laps at a time. you can tell when they go a bit greasy due to heat any way.
Edited by mrdemon on Tuesday 22 October 14:00
timlit said:
Please some advice on tyre pressures for my 3.2 Carrera for a cool and damp track day at Oulton Park.
Normal pressures as per handbook; front 2 bar, rear 3 bar.
Pressures as per sticker in the engine bay; front 2 bar, rear 2.5 bar.
Thanks
Presuming that you mean the club day tomorrow, there will be a bunch of us there in 964s (white C2, yellow RS and multi-coloured 964 cup). Happy to chat and give any advise we can. Normal pressures as per handbook; front 2 bar, rear 3 bar.
Pressures as per sticker in the engine bay; front 2 bar, rear 2.5 bar.
Thanks
Anyone had a go on this bit of kit?
http://www.autoexpress.co.uk/accessories-tyres/612...
Possibly not practical for track use, thinking about it. But I've written this now!
http://www.autoexpress.co.uk/accessories-tyres/612...
Possibly not practical for track use, thinking about it. But I've written this now!
At Spa 2 weeks ago my rear tyres started off 36psi cold. After 5 or 6 laps or so they were 45psi. I reduced them to 38psi. Another 5 or 6 laps they were 43psi. I reduced them to 38psi again. Then I forgot to check 
So in total I took 12psi out of them!
The fronts were similar.
(in a 964 C2)
So in total I took 12psi out of them!
The fronts were similar.
(in a 964 C2)
Thanks to all for the advice.
Will def. check out with the 964 guys there.
Have 12v inflator, so will mess about accordingley.
Car just has normal road tyres, and will be doing about 4 laps at a time.
Let the old girl ( and driver ) cool down at bit.
Weather forecast 14 deg C plus showers so hopefully not overheating boots too much !
Will def. check out with the 964 guys there.
Have 12v inflator, so will mess about accordingley.
Car just has normal road tyres, and will be doing about 4 laps at a time.
Let the old girl ( and driver ) cool down at bit.
Weather forecast 14 deg C plus showers so hopefully not overheating boots too much !
As has been said already you will need to adjust by a lot more than 2 or 3psi unless you are driving like a grandmother on her way to Tescos for the weekly shopping.
Tyre manufacturers will have recommended minimum and maximum pressures at which their tyres can be run. Minimum pressure is generally only a problem when you want to go racing, you have to start off low enough so that in the heat of battle the tyres reach their correct pressure. You can't ask everyone to hang on whilst you pop into the pits to check and adjust them !
On a track day you can come into the pits as often as you like and check pressure so take your time to get it right. Keep in mind that as you drive harder throughout the day the pressures will increase so just because you reached a stable pressure before lunch doesn't mean that when you start getting into the groove and driving like Senna after lunch the pressures will still be correct.
A good starting point will be to aim for your normal operating pressure whilst out on track. Check cold tyre pressure before setting off, then measure "warm" pressure when you arrive at the circuit following normal road use. Aim for that when out on track.
If you really want to know the correct pressure to run at then you need a pyrometer to measure tyre temperature. You measure inside, middle and outer temps across the tread block. You are aiming for an even temperature spread across the tyre. Inside to outside temperature is generally controlled by camber angle. Insufficient angle and the outside of the tyre gets too hot. Too much (for your driving style) and the inside gets too hot.
Tyre pressure dictates the middle temperature. Increasing pressure raises the temperature, reducing the pressure lowers the temperature. Given you can't easily change your camber angle at the circuit aim for a temperature between the inner and outer readings to give an even gradient.
Hope that all makes sense.
Henry
Tyre manufacturers will have recommended minimum and maximum pressures at which their tyres can be run. Minimum pressure is generally only a problem when you want to go racing, you have to start off low enough so that in the heat of battle the tyres reach their correct pressure. You can't ask everyone to hang on whilst you pop into the pits to check and adjust them !
On a track day you can come into the pits as often as you like and check pressure so take your time to get it right. Keep in mind that as you drive harder throughout the day the pressures will increase so just because you reached a stable pressure before lunch doesn't mean that when you start getting into the groove and driving like Senna after lunch the pressures will still be correct.
A good starting point will be to aim for your normal operating pressure whilst out on track. Check cold tyre pressure before setting off, then measure "warm" pressure when you arrive at the circuit following normal road use. Aim for that when out on track.
If you really want to know the correct pressure to run at then you need a pyrometer to measure tyre temperature. You measure inside, middle and outer temps across the tread block. You are aiming for an even temperature spread across the tyre. Inside to outside temperature is generally controlled by camber angle. Insufficient angle and the outside of the tyre gets too hot. Too much (for your driving style) and the inside gets too hot.
Tyre pressure dictates the middle temperature. Increasing pressure raises the temperature, reducing the pressure lowers the temperature. Given you can't easily change your camber angle at the circuit aim for a temperature between the inner and outer readings to give an even gradient.
Hope that all makes sense.
Henry
Last track day I did, I just filled it with fuel and drove the thing. I tested the pressures regularly and they were not too different that I didn't bother letting any air out. There were no issues with tyre wear and before anyone comments, no one overtook me all day, so I can't have been going too slowly. Best bet is to concentrate on your lines and being smooth, and you'll soon forget about your tyre pressures. If you drive like a wombat and lean heavily on your tyres, then you may want to mess with the pressures.
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