Adjusting tyre pressure for temp?

Ripp_ · Oct 3, 2021

Quick noob question, say I have the perfect tyre pressure set at a certain ambient and track temp. What do I do when the temp rises? Do I adjust my pressures based on ambient temp or track temp and by how mow much?

I've read that for every 1°C change in ambient temp I should adjust my pressures by 0.1psi and also for every 2°C change on track temp I should adjust my pressures by 1.0psi.

So which is it? And are those values correct?

I tried taking a career race seriously yesterday in preparation for joining some online races and it was just a mess lol Between practice, qualifying and race the track temp fluctuated by 15°C or so so my tyres were cooking during the 40min race so I came dead last (AI set on Hard). With only 1 pit stop how am I supposed to keep on top of tyre pressures for such a fluctuation in track temp?

eco2006 · Oct 3, 2021

I go by 0.1 psi change for 2°C Track temperature change, which works most of the time.

Ripp_ · Oct 3, 2021

eco2006 said:
I go by 0.1 psi change for 2°C Track temperature change, which works most of the time.

Thank you.

Killg0reNL · Oct 3, 2021

Keep track off your settings.
Log the used brake pads and brake duct settings.
Then log the starting pressure's for each tyre. (In conjuction with ambient and track temperature) When you have a race on that track, you got an rough estimate where to start from. When the practice session does not reflect race sessions it will be an gues. But when you do the race over, you know what to adjust to get the pressures right.

Capture the race with Twitch or YT or use a telemetry program as RST, perhaps motec logs tyre temps aswell?

But there's more to it track state, green Optimum and Fast also seem to have impact on the pressure. Starting in certain circumstances arn't the same when during the race, the track goes from WET to dry.

Last races i was off cue on tyre pressure's.

Ho3n3r · Oct 3, 2021

My rule of thumb is 0.6 PSI for every degree of track temp for the tyres that get used the most (i.e. the lefts at Silverstone) and 0.4 for the other side.

For Suzuka, and Spa, where the left vs. right is usually similar, I go about 0.5 a side per 10 degrees.

But it's strictly a rule of thumb, and normally many scenarios get tested before a race. It also depends on car/track combo.

I once had a race at Silverstone with the Aston where the difference for the start was only 0.3 for the lefts and 0.2 for the rights for 10 degrees in the specific range the race was run in.