fire_n_ice

Can any of you guys running MPSCs on C6 Z06 recommend starting cold pressures and target hot pressures for optimal grip and tire wear?

The Michelin brochure says 25/28 (F/R) cold, and 32/36 hot. However, I note that some guys prefer a couple PSI lower in the rears. Myself, I have found best performance on GY and Bridgestone runflats when the fronts are slightly higher pressure when hot, than the rears.

My camber settings are -1.2 front and rear. Track is Mosport.

Thanks in advance.

fire_n_ice

Also, I did not have Tire Rack heat cycle the MPSCs. Is this going to have a major effect on wear and, if so, is there anything I can do about it before heading to the track?

Dreamin

The MPSC's go away real fast above 35-36 hot. So I like to run 34 hot max. I run F and R at the same pressure (hot).

I think most people agree that the TR heat cycling does nothing.

fire_n_ice

Thanks, Dreamin. What would you guess as a good starting cold pressure to arrive at 34 hot? Maybe 26 or 27 psi?

linutux

I agree, Keep them under 34 hot. Starting at 28 maybe...

You should use a LOT more front neg camber: these tires LOVE it. The rear could be more as well, but probably not too much more for Mosport. I'm currently running around -2.7f and -2.0r.

You should get a good probe pyrometer, and check the tire temps after sessions to find the best pressure settings.

At VIR I kept lowering the front pressures to keep the HOT pressure the same or lower than the rears and the temps even.

I love these tires

Dirty Howie

I agree that the rear should be at least 1 lb less that the front.

I had mine down to 27F and 26R on a very hot day and they got up to 34


DH

rustyguns

29 front 27 rear for me = hot days too, we don't get much else here

vette ruminator

Why would you want the rears to start lower? My fronts heat up more so if you are looking for equal pressure (34 or so) hot, wouldn't you start lower in front? I have been playing with it and found 25 front 28 rear to be closer to 34 hot all around.

I'm asking for advice rather than preaching that my way is right...

vette ruminator

Do you leave that camber on for the street or is your Z track only? If you leave that for the street, how do your street tires hold up?

rustyguns

do what works for you, temp. humidity. weather, etc are big players in this

Dirty Howie

I'm no expert but your premise may be wrong.

Lots of guys who are very hardcore will have different pressures for right/left and front/rear depending on the track they run.

I find that I need to keep the rear pressure lower as I am much more likely to loose traction from rear coming out/around than anything else. So I want the front to come up to 34 max and the rear to stay lower.

Again .... this is my thinking and not to be taken as gospel


DH

fire_n_ice

Thanks for all the tips, guys.

I started them off at ~28 psi cold. It was a chilly day and Mosport is especially slick in the morning, when the track is cool. To be honest, took me a couple of sessions to feel 'em out and get any heat in them. Even so, I think I maxed out at 32 psi after lunch. I didn't have a chance to pick up a pyrometer, but judging by the level of grip and consistency I found, I believe I must have been close to the optimal temp range. I easily beat my best laptime on runflats by over a second.

Very impressed with the tires. Again, thanks for all the input.

fire_n_ice

Yes, I've always assumed that you adjust pressures to keep each tire within the ideal operating temp, therefore you could have each tire at a different pressure. With a lack of equipment to accurately measure temps, the poor man's way is to keep pressures equalized or within a certain range?

linutux

I've left it this way with the MPSCs on the street and they seem to tolerate it fine. I tend to drive a little aggressively.

With a lot of neg camber in the rear, there's quite a bit of 'transitioning' in moderate cornering(0.7-0.9G). It's really too much neg camber for the street and I will reset to around -1.5 when I switch back to the Generals for the winter. They don't have the rounded tread edges like the MPSCs.

linutux

This is definitely track and driver specific. I kept losing the best rotation ability, toward understeer, as the front pressure climbed higher than the rears.

Knowing what change makes the difference you want in the car's performance is one of the really challenging aspects of racing... I mean HPDE...

Being able to tell if you made the RIGHT difference is much harder though. Often, the most comfortable setup is not the fastest.

Coldmale

Interesting

I always ran mine at 36 Hot, 29 front/30 rear cold. The brakes/engine heated up the fronts

I have never tried to go lower as Michelin produce a guide book (although aimed at Porsches) that maintains 36 is the correct figure

I will reduce by 2psi and aim for 34 Hot and report back next week

John

ps. I use 265 x 35 x 18F and 325 x 30 x 19 rear as that is all that is available to me locally.

Poor-sha

On camber - I was running -1.5 in the front and noticed that the outside edges were wearing badly. I bumped it up to -2.5 but the outside edges were still corded after two more track days while the rest of the front was in pretty good shape. I'll be interested to see how long your fronts hold up at -1.2.

FWIW the rears are still in great shape but I'm moving to Hoosiers now.

Coldmale

I am running 2-1/2 front and 1-1/2 rear negative

Dirty Howie

I have the 285x30x18 fronts....

Coldmale

Are they OK on the 18" x 9.5" stock wheels?