trackday tyre pressures - up, down, or road?
Discussion
The objective is not even tyre wear- if you are trying to achieve even tyre wear you will end up running them far too high and getting the surface too hot. You'll increase your stopping distances and reduce overall grip.
Depending on the tyre type and profile you can expect heavy wear on the front outer shoulders. This is normal for a car / tyre which is not built for the track.
The answer, where the car has manufacturer recommended tyre pressures, is not to significantly exceed these in dry conditions. I would typically reduce the pressures from the recommended road pressures by 3-5psi and trim them down again to the desired pressure after a session when they're hot.
Once the tyres cool again your cold pressures will be all over the place. Cold pressures for the Lotus we run (at a clockwise circuit) would be something like;
Left Rear = 24psi
Right Rear = 25psi
Left Front = 25psi
Right Front = 26psi
These all end up being 30psi when hot which we reckon is our optimum.
Depending on the tyre type and profile you can expect heavy wear on the front outer shoulders. This is normal for a car / tyre which is not built for the track.
The answer, where the car has manufacturer recommended tyre pressures, is not to significantly exceed these in dry conditions. I would typically reduce the pressures from the recommended road pressures by 3-5psi and trim them down again to the desired pressure after a session when they're hot.
Once the tyres cool again your cold pressures will be all over the place. Cold pressures for the Lotus we run (at a clockwise circuit) would be something like;
Left Rear = 24psi
Right Rear = 25psi
Left Front = 25psi
Right Front = 26psi
These all end up being 30psi when hot which we reckon is our optimum.
When you watch a race car come into the pits, one of the first things a decent pit crew will do is check tyre pressures.
This is because it is all about hot tyre pressures, not some magical cold tyre setting. Go out, do 3 or 4 laps, come in, check and adjust and so on. Cold pressures will just be what you end up with from your ideal hot pressures and will vary totally depending on conditions. Sticking 30 cold in a tyre on a cold, damp November morning is very different than putting 30 in in weather like this, or even on the sunny side of a car. It's the hot pressures you want.
This is because it is all about hot tyre pressures, not some magical cold tyre setting. Go out, do 3 or 4 laps, come in, check and adjust and so on. Cold pressures will just be what you end up with from your ideal hot pressures and will vary totally depending on conditions. Sticking 30 cold in a tyre on a cold, damp November morning is very different than putting 30 in in weather like this, or even on the sunny side of a car. It's the hot pressures you want.
There is no golden rule here. It largely depends on the sidewall of the tyre involved. Some tyres will not take kindly to the forces put on them by track use and the sidewall will effectively "fold" under hard use, for these tyres you may need to run increased pressures. With others they will respond better to reduced pressures.
Best thing to do is start out with your normal "cold" road pressures that you are happy with - go out and do a session and then immediately adjust the tyres back down to the starting cold pressures - if the car feels good and balanced doing this then keep targeting your normal cold pressures all day - this way you know the tyre is in a window that it is comfortable operating with and you are happy with the balance. If it doesn't feel good at these pressures you have to experiment, but don't move more than 2-3 psi in any direction at once.
Best thing to do is start out with your normal "cold" road pressures that you are happy with - go out and do a session and then immediately adjust the tyres back down to the starting cold pressures - if the car feels good and balanced doing this then keep targeting your normal cold pressures all day - this way you know the tyre is in a window that it is comfortable operating with and you are happy with the balance. If it doesn't feel good at these pressures you have to experiment, but don't move more than 2-3 psi in any direction at once.
QBee said:
Our 1060 kg TVRs like low pressures.
I run 22 front and 24 rear on the road.
On track I run the same and when they get to the high 20s, let some air out.
Put 30+ psi in the TVR on cold tyres and it behaves like the road is wet.
Pah! Call that low?! I run 22 front and 24 rear on the road.
On track I run the same and when they get to the high 20s, let some air out.
Put 30+ psi in the TVR on cold tyres and it behaves like the road is wet.
On my Ariel Atom running AO48r's on track, I run around 11 psi front and 15 psi rear (HOT).
I know its a bit of an oddity, but as bizarre as it sounds, its what works
Slightly off topic, but holy dick hair tyres really are everything. After years of being a bit disappointed with how poorly the RX-7 handled versus a couple of MX-5 I've driven, trying all sorts of pressures, going to different specialists for tracking/setups and considering all sorts of anti-roll bar and suspension options, I bit the bullet and bought some Yokohama AD08R. I may as well have been sitting in a different car, and the difference is noticable even at low speeds.
Every track day guide you can find always stresses the importance tyres have, and I always 'knew' it, but the temptation for speed is always for more power from the engine, rather than something boring like tyres that can surely only make a small, even if definitely positive difference.
I could detune it back to a stock 280bhp rather than the 320+ it is now, and it would be substantially quicker than it was yesterday on the lesser tyres.
Whereas before I could brake reasonably hard in the dry and feel and hear the ABS chirping as it squirmed and came to a stop very quickly, now it brakes even harder and firmer and I've not dared brake hard enough for ABS to cut in yet.
I knew tyres and brakes are the first thing you should ever do over any lowering or power increases, and I'd have recommended that myself, but these tyres really are incredible. It's like having a new car again.
Anyone else run AD08R's? It's a road car so I didn't go for anything more track centric.
Every track day guide you can find always stresses the importance tyres have, and I always 'knew' it, but the temptation for speed is always for more power from the engine, rather than something boring like tyres that can surely only make a small, even if definitely positive difference.
I could detune it back to a stock 280bhp rather than the 320+ it is now, and it would be substantially quicker than it was yesterday on the lesser tyres.
Whereas before I could brake reasonably hard in the dry and feel and hear the ABS chirping as it squirmed and came to a stop very quickly, now it brakes even harder and firmer and I've not dared brake hard enough for ABS to cut in yet.
I knew tyres and brakes are the first thing you should ever do over any lowering or power increases, and I'd have recommended that myself, but these tyres really are incredible. It's like having a new car again.
Anyone else run AD08R's? It's a road car so I didn't go for anything more track centric.
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