Track Day Tyre Pressures

[chimhunter]

Hi gang,

Chim 4.5 running S-03s. What pressure should I be looking at for a track day? Assuming I'm on about 22/24 for road driving should I be at 24/26 on the track, or higher or lower?

Thanks,

Rob

[trefor]

Well leaving mine where they were (22/24) and doing 5 laps of cadwell park in cool weather the other weekend resulted in pressures of 27/29. I decided this was enough and didn't add any air.

I'd be more worried about one tyre being massively over/under the others (in proportion). Sometimes brakes binding or dodgy geometry could give you say 35psi after a few laps on one side and 28 on the other. = different grip from each side.

[Size Nine Elm]

For sprints, I generally leave the pressures at road pressures (22/24 cold). If wet/damp, I might even drop a couple of PSI. I find things get a bit too squirmy if I up the pressures even a couple of PSI - and sprinting hardly gives enough time for the tyres to get hot.

Your mileage may vary according to your driving style though...

[mtvrg]

I add 2-3 psi all round for the occasional trackday I do, but when getting some expert instruction from Jay Shephard at Bruntingthorpe earlier this year he reckoned adding a little more air still in order to support the tyre walls better. (I couldn't tell the difference meself).

This on S-02's on a 4l Chimaera - I now have S-03's but inflate them the same amount as the 02's.

Hope this helps?!

[jj.]

I know that most people recommend that you inflate your tyres for track use. I think you personally have to judge it. After my last track day at Silverstone, I set the pressures at 22/24 (cold). After my first session, I found I had less grip on the front as I felt I should. So after checking the pressure when warm, the front had risen to 28. After letting 2 psi out, they felt much more planted. I was running SO3's at the time.
jj

[chimhunter]

Thanks guys. Gotta love this forum...

Rob

[GreenV8S]

mtvrg said:

I now have S-03's but inflate them the same amount as the 02's.

I've found that the 'sweet spot' for S03s is a couple of psi softer than for the equivalent S02s.

[tvrbob]

GreenV8S said:

mtvrg said: I now have S-03's but inflate them the same amount as the 02's. I've found that the 'sweet spot' for S03s is a couple of psi softer than for the equivalent S02s.

Yes, absolutely right. Guess it's the harder side walls on SO-3's. If they are inflated to SO-2 pressures they get a bit skitty under hard cornering. Take a couple of psi out and they feel as grippy as your old SO-2's. Track day pressures I don't know for SO-3's but on the road they loose up on cornering if the rears are high. I would guess it's the same on track. I'd try cold pressures of 20 - 22 for road and 22 - 22 on track. As mentioned earlier, you should expect the pressures to rise by 5ish PSI once you've warmed them up. This is as a result of using moist air, the water content in your tyres will evaporate and increase the vapour pressure.

[M@H]

HI, I go 2-3psi over with the S02PP's on track.. amazingly you can really feel the difference of an extra 10% of pressure.

Cheers,
Matt.


>> Edited by M@H on Wednesday 29th October 16:38