Q&A

I've been trying out a couple of different pressures with my MPSC's the last 3 track days.
(2 x Spa Francorchamps, Belgium + 1 x Zolder, Belgium)
Have to say i am very happy with having 2.0 bar / 29 Psi front and rear (warm).
Came from 2.2 front and 2.4 rear (warm of course) I am breaking my own lap records every time so can only conclude the combination of all individual pieces seems to work for me best this way

http://www.youtube.com/user/ParadisePorsche

runet

I usually run the same (2.0 bar hot) front and rear on the Toyo R888 as well, after being advised by a racing driver that was several time national champion racing GT3s. He also ran MPSC at this pressure, and this seems to be working fine on these cars.

I haven't experimentetd much though, but is pretty happy running 2.0bar.

Crazy Canuck

34 psi hot all around has been good for me.

pranqster

I have run through many sets at 34-35 back and 32 front. I change from side to side depending on how the tires are wearing. I run them until they start sounding different, which means they are ready to cord.

Would not take them on banking though if the were getting thin.

996FLT6

31 hot works for me on mpsc's. Mike

KOAN

I like R35-36, F32 hot

Chris R.

32psi hot for me all around.

Kaizu

Interesting...

Do you base your optimal tire pressures on data logs? You should if you know how to drive. Q&A does so and finds 2.0/2.0 good, what about you else?

If you drive now with e.g. X PSI, have you tried to datalog with X-1 and X+1 PSI pressures as well to see which is really faster, and no gut feeling? (Given similar heat cycle in tires)?

I drove years with 2.2/2.4 bar, now I have them lower, especially 2.4 at rear seems a bit high, but I must confess I haven't really optimized the situation and I have not tried data logging with even lower pressures yet...(because I have had so many things changed etc. so haven't fine tuned the tire pressures yet...but according to the lap times compared to any other car and driver I am definately in the correct area... )

Q&A

Thanks Kaizu for giving this thread it's life back.
(and if Finnish people start to talk about racing ...... I listen even more careful ;-)

I also read about the most common pressures used and felt that when riding faster and faster the car began to slide more and more. This is because once you are able to increase speed (better lap times) your tires will get warmer then before. Warmer tires result in a higher pressure and this will cause the tire surface to become not flat anymore as it was but become more "swollen" and therefore you only drive on 25% of the surface. This will generate even more heat on that area resulting in sliding and overheating that part of the tire.

So my point is ....... if you are driving your laps after laps, same speed, then keeping your pressure is the way to go.

If you are up for a challenge and trying to gain 3 or 4 seconds don't be afraid if the car starts to slide a bit. Pit and measure your tires and don't be afraid to decrease the pressure with 0.2 or 0.3 bar.

I have ran on 1.3 cold tires the last time before heating them up and even then these tires are pretty stable and firm so now worries of driving on 2.0 or 2.1 bar ever

NXI20

Hi

I think we spoke at Spa regarding brakes? I run PF discs & you were on standard Porsche IIRC.

The best way to determine optimum pressure is to use a pyrometer and then aim for less than 10 degrees temperature variation across the width of the tread. For my setup (Motons, fully rose jointed suspension & 2.5 degrees camber all round), I've landed on 28.5psi F and 30.5psi rear.

I can easily get 8-10 trackdays from a set of MPSC using these settings, including driving to & from the track.