R888 - What tyre pressure?

[mr2_mat]

Hi there

Just wondered if anybody has any recommendations on what tyre pressures to run on a track day, using Toyo R888's all round?

Last time we started at standard road pressure, but this rose to around 40-41psi all round after they had heated up.

Any recommendations? - Higher or lower, or keep them at that?

Cheers.

[Rowland]

Standard wheel sizes?

If so you won't be far out starting with 26psi front 28psi rear. (Cold)
Measure the tyre pressures when you come in from your session and use that to make minor changes as you see fit.

Hope this helps.

[Tomiam]

I do exactly what Rowland just said, including the psi. Always works for me

[Hybrids]

I concur
26 & 28

Wet I run 28 & 30

[mr2_mat]

Thanks for the replies... Sorry, I should have said in my original post, yes this is with standard wheel sizes!

So, if I start with those pressures when cold, what should the pressures be when hot? i.e. when measured immediately following a session on track... As I said earlier, we were getting around 40-41psi all round when "hot".

This is our first track car, so we are starting from scratch here!... Some people have told us to drop the pressures to improve grip, whilst others have told us to increase pressures to reduce wear!... I am hoping we will get to a nice happy medium somewhere!

Also, maybe a stupid question, but on a completely dry day, is there any detremental effect if we were to swap the left and right sides around (for track use only - we would swap back again for the drive home)? - The tyres (grooves) would essentially be running the wrong way, but does this matter in the dry?... Only asking, because I envisage the left sides wearing out first, as most tracks are run in a clockwise direction.

[Hybrids]

I believe there are too many variables to give an accurate hot pressure.
Your driving style, track, weather, the time it takes to get back to the paddock etc.

starting at 26 & 28 seem to be the benchmark.
What I would possibly suggest is get a Pyrometer or infared thermometer and check your tyre temps when you come in and up or down the pressures to even out the temps.
The problem is you can end up spending half a day playing with temps & pressures for info that possibly is only relevent to that track in that particular weather.

(It has been mentioned to me in the past to aim for 32 & 34 hot)

HTH's

[jonb-]

The problem is you can end up spending half a day playing with temps & pressures for info that possibly is only relevent to that track in that particular weather.

(It has been mentioned to me in the past to aim for 32 & 34 hot)

HTH's

I've done that before, and have a note book full of temperatures to prove it

[mark73]

Th problem with the r888s is when the pressures get to high they then wear the centre out of the rear tyres.I normally start with 25F 27R but run them on nitrogen not air so they dont rise to much throughout the race


_______________________________
750MC MR2 Class B champion 2008