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Re: Track tire pressure?
Quote:
Cram said:
with cold tires i'm 17 rear and 16 front. Then under warm i keep them with not higher then 21 rear and 20 front.
Or 1,7 rear and 1,6 front cold and 2,1 rear and 2,0 front hot. With this setting i'm racing for 25 Minutes and tires are then regular used.
That kind of tallies with what I said initially.
Quote:
ADias said:
The conventional wisdom is that high-speed pressures should be higher... you guys are dropping from 30+PSI to 17PSI ??
I think Marc was referring to 1.7 bar....
Re: Track tire pressure?
Quote:
ADias said:
The conventional wisdom is that high-speed pressures should be higher... you guys are dropping from 30+PSI to 17PSI ??
O.K., it could be just me; but I use lower tire pressure at the track compared to street use. The idea being to generate more grip at the expense of mileage.
The 1.7bar mentioned above would still be about 24 or 25psi.
Re: Track tire pressure?
Quote:
Gladstone said:Quote:
ADias said:
The conventional wisdom is that high-speed pressures should be higher... you guys are dropping from 30+PSI to 17PSI ??
O.K., it could be just me; but I use lower tire pressure at the track compared to street use. The idea being to generate more grip at the expense of mileage.
The 1.7bar mentioned above would still be about 24 or 25psi.
At high speed (150MPH+) the centrifugal forces are enormous and they badly affect an under-inflated tire. What do professionals use on a race?
Re: Track tire pressure?
Quote:
Gladstone said:Quote:
ADias said:
The conventional wisdom is that high-speed pressures should be higher... you guys are dropping from 30+PSI to 17PSI ??
O.K., it could be just me; but I use lower tire pressure at the track compared to street use. The idea being to generate more grip at the expense of mileage.
The 1.7bar mentioned above would still be about 24 or 25psi.
That's right, but that is "cold" temperatures. Hot temperatures usually vary by 4 - 6 lb/in2 higher in my experience.
On the track you reduce the pressure and as your laps increase the tyres get hotter therefore increasing the pressure.
When at Spa this year, I went out with cold tyres and the rears were at 40lb/in2 and came in after 3 laps as I nearly wrecked the tyres. Due to the outside temperature (must have been 30+ deg. C) and the track temperature itself, my tyres went to 50lb/in2 in the rears an increase of 10lb.
So, what I should have done was reduce my pressures in stages. If I reduce the pressure after the 3 laps to 30lb (HOT) then when cold they'll be 20lb which is far too low for road use....hence why you should adjust temperatures every one or two laps until your happy with the setup/performance.
Re: Track tire pressure?
Quote:
ADias said:Quote:
Gladstone said:Quote:
ADias said:
The conventional wisdom is that high-speed pressures should be higher... you guys are dropping from 30+PSI to 17PSI ??
O.K., it could be just me; but I use lower tire pressure at the track compared to street use. The idea being to generate more grip at the expense of mileage.
The 1.7bar mentioned above would still be about 24 or 25psi.
At high speed (150MPH+) the centrifugal forces are enormous and they badly affect an under-inflated tire. What do professionals use on a race?
For the track you'll have to drop the cold tire pressures an additional 10/20%. Track operation will get tires hotter (increasing the cold-to-hot pressure range) so starting at say 30/32 psi now should bring you up to the
same temperature (and pressure) that 35/39 psi gave you for the street.
Don't even think about running these low track cold pressures on the street.
Well that was just a quick cut and paste. They didn't mention that Speedway pressures will be higher than Road Course pressures. I'm just guessing by your reference to 150MPH+, that you were thinking more of a Speedway.
Re: Track tire pressure?
I drop my tyre pressure between 0.3 and 0.4 bars when i do track.
As it has been said, with the high temparature the tyre will go back to the normal pressure. Otherwise you get to pressures that are much too high and you ruin your tyre.
when I leave the track, I inflate my tyres by the 0.3 or 0.4 I had taken off the go back on the road.
It only takes me about one lap, max two, to be at the normal pressure when I start with deinflated cold tyres.
As it has been said, with the high temparature the tyre will go back to the normal pressure. Otherwise you get to pressures that are much too high and you ruin your tyre.
when I leave the track, I inflate my tyres by the 0.3 or 0.4 I had taken off the go back on the road.
It only takes me about one lap, max two, to be at the normal pressure when I start with deinflated cold tyres.
Re: Track tire pressure?
Yes i was talking in Bar. I do the swiss Porsche championship with Michelin cup road and as i said before. I put my pressure with cold 1,7 front and 1,8 rear.
After 3 laps they go up to 2,2 front 2,4 rear and i bring them down to what should be the pressure on a daily basis and written in the manual. 2,0 front and 2,1 rear with warm.
At the end of my race my tire are consumed same same on the all tire. This is what i do and what i notice. For me it's perfect like this.
After 3 laps they go up to 2,2 front 2,4 rear and i bring them down to what should be the pressure on a daily basis and written in the manual. 2,0 front and 2,1 rear with warm.
At the end of my race my tire are consumed same same on the all tire. This is what i do and what i notice. For me it's perfect like this.
Re: Track tire pressure?
The primary reason for adjusting tire pressure is to keep the tire as the optimum temperature for traction. It's not about about saving tire wear. If you want to protect your tires, don't go to the track at all. If you want traction, you measure you tire pressure so that it hits a certain target when the tires are fully warmed up. If the pressure it too high, the tires get too hot, and they get very slippery.
On a warm track day, in my C2S with Micheling PS2, I aimed for 36/39 PSI (front, rear) when fully hot. Note that when the tires cool off, they will be significantly below the Porsche recommended street pressure, so you'll need to fill them up again.
On a warm track day, in my C2S with Micheling PS2, I aimed for 36/39 PSI (front, rear) when fully hot. Note that when the tires cool off, they will be significantly below the Porsche recommended street pressure, so you'll need to fill them up again.
Re: Track tire pressure?
Quote:
adam s said:
running Toyo R888's ?? what rims was that with?
I am not finding matching sizes for those wheels...
any recommendation for a track tire ro replace the cups?
nittos? toyos?
Adam, they were not standard rims you're right. But I'm not sure of the size.
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