Talk to me about tyre temps / pressures
Discussion
Doing MSV day at Bedford on 01 August, full day on the GT circuit in a borrowed Renaultsport Megane Cup 250 (from my brother). I’ve done a reasonable amount of track driving before but always in someone else’s car (Palmersport a few times, other cars as second driver etc).
Wanted to see what the best way is of dealing with tyre pressures on a track day - the car will have brand new Michelin PS5s on it and I don’t want to wreck them! Do you turn up, get the tyres warm with a few laps and then reduce pressures to get to what you think is best with the temp in the tyres, or do you reduce pressures first, then go out to warm up the tyres? I’m guessing the latter?
Also any views on what would be a sensible set of pressures for a Megane on track? I’ll do some experiments during the day to see what feels best, but would be good to know roughly where to start, if anyone has any ideas.
Thanks all in advance.
Wanted to see what the best way is of dealing with tyre pressures on a track day - the car will have brand new Michelin PS5s on it and I don’t want to wreck them! Do you turn up, get the tyres warm with a few laps and then reduce pressures to get to what you think is best with the temp in the tyres, or do you reduce pressures first, then go out to warm up the tyres? I’m guessing the latter?
Also any views on what would be a sensible set of pressures for a Megane on track? I’ll do some experiments during the day to see what feels best, but would be good to know roughly where to start, if anyone has any ideas.
Thanks all in advance.
As a very simplified guide, start with the tyres at the recommended pressures (cold), go out and do a few laps and while still hot, drop the pressures back to the recommended numbers (fronts will probably need much more let out on your car). Repeat a few times initially and then check occasionally through the day (you'll probably get faster, hence tyres hotter). At the end of the day when cooled down, remember to reinflate back to recommended pressures for the drive home (maybe note down the individual cold pressures for next time).
Welshbeef said:
Should you not be nipping to Costco for nitrogen in the tyres which will help / hold the pressure
I’m not aiming for a podium finish at the track day 
Thanks all, will take your advice. Come say hello if you’re at Bedford on 01 August, I’ll be the red Megane with under inflated tyres.
Didn’t they do a comparison sometime ago on fifth gear.
The outcome was that the nitrogen pressures fluctuated but not as much as ordinary air.
Given the cost of the nitrogen and it’s availability I believe their conclusion was a bit 50-50.
Of course we are relying on my memory which according to my wife is appalling!
The outcome was that the nitrogen pressures fluctuated but not as much as ordinary air.
Given the cost of the nitrogen and it’s availability I believe their conclusion was a bit 50-50.
Of course we are relying on my memory which according to my wife is appalling!
phazed said:
Didn’t they do a comparison sometime ago on fifth gear.
The outcome was that the nitrogen pressures fluctuated but not as much as ordinary air.
Given the cost of the nitrogen and it’s availability I believe their conclusion was a bit 50-50.
Of course we are relying on my memory which according to my wife is appalling!
You are 100% correct sir, well remembered. The outcome was that the nitrogen pressures fluctuated but not as much as ordinary air.
Given the cost of the nitrogen and it’s availability I believe their conclusion was a bit 50-50.
Of course we are relying on my memory which according to my wife is appalling!
alicrozier said:
As a very simplified guide, start with the tyres at the recommended pressures (cold), go out and do a few laps and while still hot, drop the pressures back to the recommended numbers (fronts will probably need much more let out on your car). Repeat a few times initially and then check occasionally through the day (you'll probably get faster, hence tyres hotter). At the end of the day when cooled down, remember to reinflate back to recommended pressures for the drive home (maybe note down the individual cold pressures for next time).
Exactly this, I use a Megane 250 Cup with Michelin MP4Ss which on the road runs 34 front, 31 rear. I go out, do a short stint then check the tyres immediately I come in and reduce the hot pressures to 34/31.
I might reduce a bit more as I go through the day if I'm doing longer sessions/trying harder.
It's a lot easier if you have a decent gauge with a pressure release button!
This seems to work well, I haven't had the feeling that the tyres are going off due to overheating.
One thing I am careful of, I usually give it a few corners to get some heat into the tyres when I go out as I'm worried that if I go too hard too early on underinflated (until hot) tyres I may do some damage. And the TPMS may have a hissy fit but just ignore it!
I do it very differently.
If the car feels wobbly/lazy/imprecise during side to side transitions increase front tyre pressure.
If it is imprecise and wobbles into oversteer, increase rear tyre pressure.
If the car feels sharp, but looses grip too early and too quickly reduce the tyre pressure.
Get an IR heat probe and check the temps across the tread when you come in.
Adjust your pressures to keep the temps as even as possible, and think about both what camber changes AND a different driving style could do to help.
Driving style? Think about how much steering lock you are using. Try using less.
Don’t stray too much from the manufacturers settings at the start, or if you have an odd tyre size… find out what your axle loads are and check what tyre pressure the ETRTO recommends.
There are two main things to consider. What are the influences on the control of the mass from a sub optimal tyre pressure in the tyre AND what is going on at the tread. At the tread, with road tyres, generally try to keep the temp down and even across the tread.
If the car feels wobbly/lazy/imprecise during side to side transitions increase front tyre pressure.
If it is imprecise and wobbles into oversteer, increase rear tyre pressure.
If the car feels sharp, but looses grip too early and too quickly reduce the tyre pressure.
Get an IR heat probe and check the temps across the tread when you come in.
Adjust your pressures to keep the temps as even as possible, and think about both what camber changes AND a different driving style could do to help.
Driving style? Think about how much steering lock you are using. Try using less.
Don’t stray too much from the manufacturers settings at the start, or if you have an odd tyre size… find out what your axle loads are and check what tyre pressure the ETRTO recommends.
There are two main things to consider. What are the influences on the control of the mass from a sub optimal tyre pressure in the tyre AND what is going on at the tread. At the tread, with road tyres, generally try to keep the temp down and even across the tread.
Kawasicki said:
I do it very differently.
If the car feels wobbly/lazy/imprecise during side to side transitions increase front tyre pressure.
If it is imprecise and wobbles into oversteer, increase rear tyre pressure.
If the car feels sharp, but looses grip too early and too quickly reduce the tyre pressure.
Get an IR heat probe and check the temps across the tread when you come in.
Adjust your pressures to keep the temps as even as possible, and think about both what camber changes AND a different driving style could do to help.
Driving style? Think about how much steering lock you are using. Try using less.
Don’t stray too much from the manufacturers settings at the start, or if you have an odd tyre size… find out what your axle loads are and check what tyre pressure the ETRTO recommends.
There are two main things to consider. What are the influences on the control of the mass from a sub optimal tyre pressure in the tyre AND what is going on at the tread. At the tread, with road tyres, generally try to keep the temp down and even across the tread.
Why have you not tried nitrogen? Would dramatically eliminate all of the aboveIf the car feels wobbly/lazy/imprecise during side to side transitions increase front tyre pressure.
If it is imprecise and wobbles into oversteer, increase rear tyre pressure.
If the car feels sharp, but looses grip too early and too quickly reduce the tyre pressure.
Get an IR heat probe and check the temps across the tread when you come in.
Adjust your pressures to keep the temps as even as possible, and think about both what camber changes AND a different driving style could do to help.
Driving style? Think about how much steering lock you are using. Try using less.
Don’t stray too much from the manufacturers settings at the start, or if you have an odd tyre size… find out what your axle loads are and check what tyre pressure the ETRTO recommends.
There are two main things to consider. What are the influences on the control of the mass from a sub optimal tyre pressure in the tyre AND what is going on at the tread. At the tread, with road tyres, generally try to keep the temp down and even across the tread.
Kawasicki said:
Welshbeef said:
Why have you not tried nitrogen? Would dramatically eliminate all of the above
Honestly, these days, I am not sure if people or joking or not.But I am going with joke here… and it did make me grin, so cheers!
I only have Michelin tyres and plan buying them always when on special offer/discount so extremely reasonable.
Welshbeef said:
Kawasicki said:
Welshbeef said:
Why have you not tried nitrogen? Would dramatically eliminate all of the above
Honestly, these days, I am not sure if people or joking or not.But I am going with joke here… and it did make me grin, so cheers!
I only have Michelin tyres and plan buying them always when on special offer/discount so extremely reasonable.
I always reduce mine but it’s almost impossible to keep them at the correct temperatures unless your sessions are exactly the same lap after lap.
People give precise numbers but in reality you will only see those numbers for a lap or two, they will be cold and low when you get on track, reach the right temps, then another few laps be to high.
One clean fast lap will be different temps to getting held up for half a lap.
As long as they aren’t sky high then does it really matter?
People give precise numbers but in reality you will only see those numbers for a lap or two, they will be cold and low when you get on track, reach the right temps, then another few laps be to high.
One clean fast lap will be different temps to getting held up for half a lap.
As long as they aren’t sky high then does it really matter?
^^^^^^^^^^^^
I start with factory pressures and reduce back down when hot.
When the weather is warm it is always 7-8 psi, less in winter.
I usually check a few times during the day and it is always give or take correct.
I’m never too precious about it. Car performs well tyre wise. It is a track day after all!
I start with factory pressures and reduce back down when hot.
When the weather is warm it is always 7-8 psi, less in winter.
I usually check a few times during the day and it is always give or take correct.
I’m never too precious about it. Car performs well tyre wise. It is a track day after all!
Glenn63 said:
I always reduce mine but it’s almost impossible to keep them at the correct temperatures unless your sessions are exactly the same lap after lap.
People give precise numbers but in reality you will only see those numbers for a lap or two, they will be cold and low when you get on track, reach the right temps, then another few laps be to high.
One clean fast lap will be different temps to getting held up for half a lap.
As long as they aren’t sky high then does it really matter?
Yes, they change all the time.People give precise numbers but in reality you will only see those numbers for a lap or two, they will be cold and low when you get on track, reach the right temps, then another few laps be to high.
One clean fast lap will be different temps to getting held up for half a lap.
As long as they aren’t sky high then does it really matter?
Obviously if you are aiming for the fastest lap time you should be driving consistently so they might achieve a fairly steady pattern within 10 minutes or so. Like you say traffic can change that situation.
Now, if you are just out to enjoy your drive, then looking at the fun side of the equation plus tyre wear pattern is probably more important. I personally hate it when I wreck the tread edge and shoulder area before I have worn the rest of the tyre, so I would work on my setup and driving style to avoid that. I’m careful not to overdrive one tyre or one axle, to the point where the tread compound overheats and it becomes the clear weakest link in the system.
I have a fair amount of experience of lapping heavy road cars with road tyres, and moderate experience of race cars on slicks. So that’s what I’m basing my advice on.
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