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Track day tyre pressures?

Planning to do a track day in the 156 in a few weeks. I'm running 225/45 tyres on GTA rims and would like to know opinions on recommended tyre pressures.

I normally run about 36-37 psi on the road and guess I need to increase pressure by a few psi for the track so was thinking about 40psi.

Any recommendations?
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Re: Track day tyre pressures?

I would run between 22 and 30 psi. (cold)
but thats me, others may have other opinions. also dependant on weight of engine and such like.
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Re: Track day tyre pressures?

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Originally Posted by Enzo156 View Post
I would run between 22 and 30 psi. (cold)
but thats me, others may have other opinions. also dependant on weight of engine and such like.
FAR too low, even for the road...!
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Re: Track day tyre pressures?

I'd add a couple of bars to the high-speed rating in the manual e.g. I run 2.8 bar/40 psi on 215/45/17 tires. Lower pressure can mean more grip, at least until the tire overheats, and then it goes to pieces and you'll need new rubber

By starting with a higher pressure, you can slowly reduce it after a few laps as the tires warm up, but don't go too low that the sidewalls get scuffed or fold over. Chalking the tire and checking for wear marks also help.
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Re: Track day tyre pressures?

I start at 2.5 or 2.6 bar cold and cap at 2.8 bar warm. Your car is slightly lighter than a GTA so maybe you could get away with a bit less, not much. Above poster is spot on, monitor the sidewalls, if the wearline goes over the indicated edge of the tyre you need to increase. Lower pressures might appear to give good grip for 2 laps or so, but ruin Tyres, and you don't want the tyre coming off the rim..
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Re: Track day tyre pressures?

Thanks guys, will keep 2.8 bar as my max pressure and see how things go. Track will be pretty hot as its still 30+ degC here at the moment.
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Re: Track day tyre pressures?

lol guess thats why Im crap on track then
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Re: Track day tyre pressures?

My advice is stick to whatever tyre pressure you would use on the motorway then see how you get on
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Re: Track day tyre pressures?

I'm sure you are very quick out of the blocks though on the first lap or two

Do you not find that your tyres go off very badly, and possibly quite suddenly mid way through the session - especially if you have decent brake pads.
The tyres will get roasting hot, much hotter than if you started with high pressure.

Your sidewalls must be getting a bit of a caning too?

Of course I did the same as you initially so can vouch that all the above happened to me the first times I did track days!

Quote:
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lol guess thats why Im crap on track then
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Re: Track day tyre pressures?

but when your tyre heats up. your tyre pressure goes up also! so you may start off at 25psi and finish at 32 hot. (example) I know some of you may know this so it actually takes a few laps to get going to build the pressure and get to optimum.

now with that in mind and our level of ability. our sessions or races wont last longer then 30 mins. you have to balance out what you think is best. do you want to be relatively quick all session. or maybe push that bit harder at the start and mid session and lose a little time at the end when your tired. the car is tired etc etc etc (going at it for 30 mins is hard graft!!)

this wont work of course if your running rubber bands, IE 225/40 y18's
where the tyre will just fold over. what racing cars do you see running these tyres anyway??

the problem with going higher pressures is if you start at 40 psi. (tyre is rated max 45psi) and your tyre gets hot, pressure may well go past maximum. your really starting to take away from your grip levels.

it is a fine balance, and it differs for each driver let alone tyre brands, car set up etc.

My advice is to play with different pressures and keep an eye to see if your tyres are rolling (good tip with the chalk earlier in the thread) and see what works best for you!

make sure you write down the starting pressure (cold) because adjusting pressure when tyre is hot will leave you over inflating your tyres!


there are lots of books about all this so we are just scratching the surface here.
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Re: Track day tyre pressures?

Quote:
Originally Posted by Enzo156 View Post
but when your tyre heats up. your tyre pressure goes up also! so you may start off at 25psi and finish at 32 hot.
Yes, but 32PSI (Hot) is still too low, because the minimum Cold pressure is 32PSI..!

Overworking the tyre because the pressure is too low is very bad news.

Normal road tyres will need the pressures checking and adjusting far more during a trackday than proper race tyres would because the road tyres will be flexing and deflecting far more.
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Re: Track day tyre pressures?

32psi was an example. With compressed air you cannot gauge how much the pressure will go up because of differing water content within the air.

and 32 psi is the minimum for what exactly? road use. where the aim is to be the happy medium. to have grip but make the tyre last within the setup that the factory set.

lower your car on a set of decent shocks and the factory settings have all gone out the window! on a track day your not there to look after your tyres. you want maximum grip and optimum tyre temps.

yes over work your tyres. push them to the limit and beyond! find the right balance for you and your car! together as one
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Re: Track day tyre pressures?

It's easier to adjust tire pressure by releasing air rather than pumping air into a hot tire, so that's why having a higher initial pressure would help. 32 psi/2.2 bar is the factory standard for normal loading, but high speed/heavy load requires a higher pressure. If you have an extra-load tire, you'll need even more pressure on top of that.

The problem with running too low a pressure is that the tire itself overheats. Once you've gone around the track a few laps, the air inside will have heated to the right pressure, but the tire compound would be too hot already and starts falling apart. You'll then have reduced grip and severe tire wear. These are road tires, not race rubber...
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Re: Track day tyre pressures?

the heat of a road tyre is caused by the tread blocks moving around.
Alot of racing series in this country and others use a road tyre as a control tyre.

they over come this problem by having the tyres skimmed. Less moving blocks generating less heat! (dont goto a track day with new tyres(half to 3 quarter worn is best))
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Re: Track day tyre pressures?

Quote:
Originally Posted by Enzo156 View Post
the heat of a road tyre is caused by the tread blocks moving around.
The tyre carcase also heats up from its own movement. That movement and the heat buildup will be too much if you run low pressures.
Over heating sidewalls (from too much flexing) will suddenly fail (that is what a blowout is).


Quote:
Originally Posted by Enzo156 View Post
A lot of racing series in this country and others use a road tyre as a control tyre.
Most control tyre series use "List 1B" tyres, which are not normal road tyres at all.
They are road legal (some only marginally!) but you would never use them as a day to day tyre on the road.

Even then they still wouldn't use low pressures.
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Re: Track day tyre pressures?

I for one ran on yoki a538's which are not a pirelli zero corsa tyre. I also ran them at no more then 32psi max cold!

I have never had a tyre fall apart or blow out on me. I do have guys beatin me alot but hey, thats racin

Last edited by Enzo156; 13-11-08 at 21:43.
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Re: Track day tyre pressures?

Maybe it depends on the track temp and ambient temp. The OP was in Qatar so I guess track temp can go over 35C there. Here in Malaysia we see 30-35C track temp too, and if you were running low pressure on road tires, you just might end up skating on bare rims after a blowout
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Re: Track day tyre pressures?

Blloddy Nora!

Let's not make a meal of it.

Whatever the manufacturer's "motorway" pressure reading is, +2 PSI.

Done.


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Re: Track day tyre pressures?

Quote:
Originally Posted by Ralf S. View Post
Blloddy Nora!

Let's not make a meal of it.

Whatever the manufacturer's "motorway" pressure reading is, +2 PSI.

Done.
Which gives you 38PSI (2.6Bar)
(2.2Bar minimum + 0.3Bar for constant high speed = 2.5Bar = 36PSI + your 2PSI)

If your starting point is the std full load 2.5Bar then the same calculation gives you 42.6PSI (2.9Bar)


So we all agree (except for Enzo...)...

Last edited by David C; 17-11-08 at 10:22.
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Re: Track day tyre pressures?

hya david c i perfectly correct i would run around 60 lbs hot pressure on road legal tyres !
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