track tyre pressures...

[Globe_911]

hello again! a few weeks ago i was asking about toyo r888's in 944 sizes and got loads of usefull info. I've sourced the correct tyres had them fitted but I neew to know what pressures to run them on track? I've got a trackday coming up this friday at teesside autodrome and could do with setting them up right!
Thanks []

 

[edh]

I'd expect to run at around 30-32 hot, maybe a little less. Remember that tyres that are set to correct road pressures will heat up dramatically on track, and the pressures will shoot up.

 

[poprock]

Aye. The advice I get given every time I visit a track is to do an initial lap to heat 'em up and then let them down to a reasonable "˜warm' pressure for the rest of the day.

 

[Hilux]

Depends on what compound and how much tread.

Lots of tread on decent road tyres will cause a heat increase.

I found that tyres raised about 4 psi when hot so set them to 29psi so they ended up at about 33psi warm.

 

[lali]

NEVER start with a low pressure and expect them to come up to pressure when they are hot.

Lower the pressure as they heat up, for the frst 3 laps you really need to come in every lap. but you're aiming for 30 ish hot all round. but dont forget that the track temp is a lot lower now we're in the winter so it may take a bit longer to get them hot.

 

[edh]

you'll know when the pressures are too high as the tyres will be squealing and you'll have no front end grip []

 

[944 man]

As tyre temperature is important here; I will add that infared thermometers can be bought for about £20 + VAT, and will prove invaluable as youre struggling to work out what happens when and which temperature...

 

[Globe_911]

cheers guys. so basically set them to around 29/30 then check them after a few laps and try and keep them between 30 and 32 hot?

 

[lali]

ORIGINAL: Globe_911

cheers guys. so basically set them to around 29/30 then check them after a few laps and try and keep them between 30 and 32 hot?

no... NEVER start with your pressures LOW and then wait for them to come up to pressure/temp.

 

[944 man]

As above: start with the correct pressure and pit every few laps and check/adjust until stable.

 

[333pg333]

Having used quite a few sets of R888s I can say that we started out approx 32-34 hot, but wound up going a bit higher in fact. Many people in the US have also corroborated this. Not sure of your ambient temps, but I'd start at road psi levels and see what happens after a few laps. Also there is a school of thought to bedding or heat cycling race tyres in, but we used to pretty much get in and go with the Toyos. They seemed to get up to heat very quickly and remain good for some time. Obviously the UK will be different to OZ. Also, are you able to change your suspension geometry for the track? I found that these tyres really like a fair bit of neg camber. I got to -4 front and -2 rear but your suspension setup will dictate what you can achieve.
Bottom line, have fun!

 

[Hilux]

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ORIGINAL: Globe_911

cheers guys. so basically set them to around 29/30 then check them after a few laps and try and keep them between 30 and 32 hot?
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no... NEVER start with your pressures LOW and then wait for them to come up to pressure/temp.

Correct.

I ran mine at 33 cold all around and found that when hot (I dropped them incrementally) at 29psi the temperatures were stable.
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