TKOGTO

1st set of R-compounds.
Looking for hot and cold pressure recommendations for R888s.

fleming23

From what I have seen, you won't get a 100% straight answer. Hot pressures seem to vary from low 30s (32-33) to 40+. I would probably start 26-27 cold and go from there with a target of mid 30s, at least that is my plan tomorrow.

This is the Spec Miata guide
http://toyotires.com/sites/default/f...Guidelines.pdf

Hi Volts Z06

Heavier vehicles require more air pressure than lighter ones. The R888 has always been a very difficult tire to setup due to it being very sensitive to rim width. I would suggest erring on the side of more pressure to start (perhaps around 30 lbs cold) and the take tire temps to see what you have. That really the only right way to do it....anything else is a just a guess.

skxf430

I run 26/27 cold building to about 32/33 hot. Anything higher than 34lbs gets too greasy and slippery.

SunnydayDILYSI

I've had good success with 28 lbs cold. The triangles on the shoulder are helpful indicators. If you are scrubbing off the triangles, you probably need a bit more pressure. I run 275s up front and 305s in the back on stock C5 Z06 rims. At 28 lbs, I scrub the tip of the triangle in front and about 1/2 of the triangle in the back.

WannaC5Z

This is good to know because I am going to the track tomorrow. I'm used to running about 35lbs cold in the front tires on my former Mustang Cobra. I always run about 5lbs less in the rear tires for better corner exit grip.

Last C5

I've probably worn off 25 sets of 888s. I start at about 34 cold and aim for about 41 hot. The Miata spec didn't work for the spec Miata racers and it certainly won't work for a 3,000 lb Corvette. Running lower pressures on the Vette will wear the outsides of the tires in a hurry. The lower pressures don't hold the center of the tire on the pavement and that's why they don't feel like there is any stick after they get hot. I've had my tire temps taken at 41 hot and there was less than 5% variation across the tire. It seems counter intuitive, but watch your tire wear and don't be afraid to give the higher pressures a try.

magracy

I talked with the guys from toyo at the nasa western states nationals at laguna seca about this. they said it does vary according to vehicle wieght, camber, driving style etc. they said anywhere between 30 and 40 psi. hot. I started at 40- 41 hot during my practice session and then they took temps for me. my temps were on the low side at 150-160 deg. so I dropped down to 38 and that seemed to work for me the rest of the weekend. I run 2.5 front and 1.5 rear camber. 3425 lbs 275 front 305 rear. cold temps were 32, I run nitreogen.

C5Natie

C5Natie

I run 295/315 r18s and I start at 32psi to end up around 40-42psi and the car feels good. At 36psi hot i was seeing a little wear on the outside shoulder and it seems the sidewall likes to roll a bit. The toyos do like a little more pressure.

RDnomorecobra

I agree with the close to 40 hot opinions. C5 in my experience. 888s like more pressure than others.

SunnydayDILYSI

Good thread. These tires are really sticky at 28 cold, but might be even better at 32. I'm going to try increasing to 29, 30, 31, and 32 my next weekend out to see the difference. I've had really even wear at 28. I'm in Texas where track temps can get really hot, and I just use atmospheric air (not nitrogen or dried air). Not sure how much of a difference that makes.

Supercharged111

It only gives you a bigger swing WRT cold vs. hot temps. I've noticed the Toyo RR seems to prefer about 2psi less than the RA1, so the comment about the R888 wanting more pressure than others is likely true. Bear in mind, when talking tire temps, that all gauges seem to read differently, so these starting points are just that. Pick a cold pressure that any of the R888 experienced members have prescribed, annotate hot pressures, and observe where the wear line falls on the triangle. If you're not going to screw with tire temps and alignment at the track, then your best bet is to settle on a tire pressure, on your gauge, that makes the wear line kiss the tip of the triangle on the sidewall.

tmtraylor

My experience is the same as above, 26 Cold and anything above 34 hot is scary. It's hard for me to imagine the tires getting better at a pressure above this level, but I am no expert.

My car is a stock C5Z (DRM bilsteins), track type alignment and I run square 295/30R18 at the mostly right hand Road Atlanta. Good luck!

Tim

RC000E

Exactly my experience. You have to run these tires in the 20's.

I ran one track day years back where the surface temps were crazy. I started at 30psi and after two hot laps the car was sliding everywhere. Hit the pit and I was at 50...lol!

fleming23

This weekend at Barber Motorsports Park in my C3, I found that 31-32psi was about where they needed to be when measuring between sessions, after a 1.5 hour cool down. At low 30s hot (27 cold), I was wearing well past the triangle side markers. It is always difficult to get a true hot temp reading unless you have someone standing on pit lane.

96GS#007

TKOGTO

Update: used the R888s yesterday for the first time. As I received such a wide range of recommendations re: starting psi's, I started with out high ~33 front, 32 rear. For me, the results were not good. Tires felt quite greasy above 37. At 40, it seemed useless to continue with the grip so diminished. Second session, I started on the low end at ~26 all around. Grip remained consistent throughout. Ending levels got only to ~31. Haven't inspected wear pattern yet but did notice significant wear around the edges. I suspect starting around 29 will work best.

John Holmes

This has been my experience also.
Starting at 30 front and 28 rear has provided the best grip, the price for this is expedited shoulder wear.

blackbeast99

As others have stated, it will vary, but personally for me:

Cold ~26-27psi
Hot ~34-35psi

I forgot to deflate them once, and almost immediately on the second lap, I knew something was not quite right (well, didn't feel "normal" to me), looked down and tires ranged from 37-40 psi...For me, the sweet spot is right in the 34-35 range.