Tire temps from Laguna, Thunderhill, Sears Point - The Unofficial BMW M5 Messageboard (m5board.com)

stever · 11th July 2002, 05:12

i've collected some information from the Smartire and now i'd like to know what to do with it (PSI/F)

LF P/T RF P/T LR P/T RR P/T

Laguna Seca April 20/21
cold 34/51 34/51 36/51 36/51
end session 70F? 42/138 42/140 44/143 44/136

Thunderhill July 7
cold 35/60 35/60 36/60 36/60
end session 96F 43/176 42/179 44/176 43/172

Sears Point July 9
cold 35/60 35/60 36/60 36/60
end session 100F 41/159 41/154 44/170 44/170

Laguna Seca and Thunderhill are counterclockwise and Sears Point (okay, Infineon) is clockwise -- turn 2 at Thunderhill is a loong sweeper that puts a lot of stress on the right front, Sears Point is slower with tighter corners and more throttle steer -- Laguna and Thunderhill are tough on brakes, Sears Point pretty easy

Car -- Dinan III, 275/285 Pilot Sports on Dinan 9/9.5 wheels, 3.45 diff, StopTech brakes (Pagid Oranges Laguna, Blacks Thunderhill and Sears Point -- see Apples Garnet Paper post re my bedding problems)

greg · 11th July 2002, 09:40

steve - ain't the Smartire system great?

Anyway - i can't compare apples to apples - but at the end of my run at LSIR in the Porsche i was pushing 200 degrees on the tires. i was told by the people at Kumho (the only ones who responded to a long letter i wrote to several mfg's asking questions like this) told me that best traction on street tires is actually HIGHER than for track tires because the harder compounds need even more heat before they get increased stick.

You might try starting a few pounds LOWER and seeing if you can get higher temps - it MAY make a difference. Also, interesting that your starting and ending pressures were pretty close at LSIr and Thill - but the thill temps were so much higher. I would have expected a corresponding increase in pressure as well.

Finally - I hope someone some day does a long test with a skid pad, pyrometer and smartire. i would like to know how well the temp that smartire reads (which is the temp of air inside the tire) correlates to the tire surface pressure. It must lag, to some degree, and may reflect more brake/wheel heat - but evidently the tires are pretty good conductors, so it shouldn't be off too far in absolute terms.

Bart Carter · 11th July 2002, 18:30

If you want to know how to adjust your suspension or tire pressures, you need to read tire temps accross the treads. See "Tuning with tire temps" in the Tips and Tricks threads.