For a 1300kg two wheel drive car doing five lap sprints. Reason I ask is that I've never used them before and previous experience with Kuhmo's involved a fair bit of experimentation getting them right.

So any cold/hot suggestions, any tricks? Won't be able to do the proper heat cycling at the start, unless running them on the road with low pressures will do that.

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Hey Richard, I run from 28-30 psi cold from memory (it's been a while) on my 180SX, and that seemed to give the best results.

What time period will they be driven for? 5 laps on one circuit can take twice as long as on another, which means the amount of heat generated will differ.

Assuming a 1:45 lap (which is about average for most of the track times I've seen) I'd probably go for around 28-30psi cold. Its the hot pressures which matter the most, so as soon as you park the car up check your tyres. I normally aim to have my RE55S' at around 32-34psi when I come off the track.

There is no "absolute" answer to this as there are many variables, even with the same car.

A tyre pyrometer is your friend here and will give you instant feedback as to what your surface contact patch looks like. I got a Longacre unit from USA for ~$100 delivered and since then I have lots of "friends" on track days

Goodoh, thanks blokes, sounds like the RE55's are fairly convential, unlike the Kuhmos which worked ~22psi.

On a 5 lap sprint ive started with 24 psi, Goes up to 28-30 psi

I aim for 34 hot. on a low power 32 gtr doing 15 min sessions it is generally:

-8 front outside
-6 front inside
-6 rear outside
-4 rear inside

try that as a starting point, and check pressures after 2 flat out laps without a cool down.

which kumho's? I'm thinking about a set for the next track nugget but it weighs around 1050 so was considering a softer compound..

i assume 22 is cold pressure?

i have my RE55s SR2 for 5 x hotlaps of QR at 28 cold. come off at 34.

V70A's, they have a very stiff sidewall. Yeh ~22 cold.