Air Pressure recomendation for R888's

[hrg88]

I have my first race in the 02 coming up and need cold and hot air pressure recommendations for the Toyo R888's. I only have 2 track sessions so I don't have much time to dial it in.

[jgerry2002]

Here is an interesting debate. I'd think you'd want to run them with a bit more starting pressure.

http://forums.bimmerforums.com/forum/showthread.php?t=1192079

I ran them for two days at a BMW CCA HPDE at NJ and did have some accelerated center wear in the fronts as described in that thread. I was around the normal suggested 39psi hot, I will try to bump pressures up a little during my next 3 track days which are scheduled for two weeks from now and potentially tighten up my rear sway bar a little, as I was slightly overbraking (left foot trailbrake) to get the front to really bite on turn-in. It could be front tire pressures, or it could be the rear sway.

FYI, I am running 205/55 14 with fixed camber plates, eibach springs, bilstein sports, Metric 1" bar in the front, random adjustable bar in the rear. The whole stance of the car is raked forward slightly. E12/E21 front brakes, stock rear, and carbotech XP-10 pads on all 4 corners....

[c.d.iesel]

start at 36psi all round and adjust from there

every car, suspension, driver preference for feedback,

track, weather conditions, rim width, tyre size,

rubber compound, alignment(camber settings) is different

[Freddie]

I start at 28 cold and come off at 37 hot. Seems to work well for the entire session. Any higher than 37-38 off the track the car gets very loose halfway into the race and times fall off.

[hrg88]

Toyo says 32 - 38 hot, I don't feel right about starting at 38. I will wait to see if any others are starting at these high #'s, or else I will start at 28 and see if I get to 37 or 38 after the qualifying session.

BTW, these are 205/60-13's with -2.5 front camber and I think I am set to -1.75 rear, but would have to look at my setup sheet at home. I'll get a weight at Pocono, but I am guessing about 2200 LBS.

[c.d.iesel]

....and you then have to compensate for the higher altitude of POCONO

air is thinner there !

[TobyB]

ohhhhh.... welcome to the 888 wormcan.

I started at 30 psi cold, and spent a whole season letting air out of them.

I think I finally got down to 26 psi hot by the end of the season.

I played a bit with using pressure for balance, but that seemed to

give pretty even tire temps, biassing towards a slightly warmer inner edge.

Keep in mind that the tire/rim combo has a big effect- I was using

205-60-13's on 7" rims.

The Pro3 bunch would come off track with pressures well into the 40's

and also have even- ish temps with a 225-60 (?) 15 on 7" rims.

Others played with much lower temps.

We all came to the conclusion that we didn't know shit.

Then Toyo started making the RA1 again, and I went to slicks.

Still don't know shit.

I only have 2 track sessions

then assuming rational tire sizes, try 30-32 to start. It won't kill you.

If you can get hot pressures afterwards, targetting 34-38 is a very safe

range.

These tires take a while to dial in, depending a LOT on how much camber

you use. There are also 2 schools here- the 2ish school and the 5ish school.

Which works best is a mystery.

hee

t