Post track tyre condition

[demolitiondan]

I reckon a lot of this is down to driver preference. Having completed over 30 rallies (tarmac and gravel) you realise there's always going to be a compromise. If you up the pressures the sidewalls are going to be stiffer but if you start with low pressures they are going to be optimum after a bit of warming up.

Personally I cannot stand the feeling of under-inflated tyres - the car seems to settle one way and the other on the tyres but I don't like over-inflatig either. Having done a fair bit of development work I have settled on almost manufacturers spec tyre pressures for the rally car which is now 50 Kg lighter than standard and with 2.5 times the horsepower.

If I try a track day in my road car I'll be sticking with standard tyre pressures - it's simply not worthwhile ing around in the pits when you can be out on the track having fun!

[Pierscoe1]

>What a load of bollox

A bit uncalled-for..

As I said, I'm no expert, but was just going from what I'd been told by regular track-day-ers and trackday organisers...

there seems to be a massive ammount of conflicting opinion on this matter, although most seem to think that although rasining pressures might not be the best for ultimate grip, it will help make the tyres last a bit longer due to decreased distortion etc.

[johnny senna]

You will have less bother if you get some R-compound tyres for track use only. You will need to buy some cheap wheels which you will change at the track.
Normal road tyres quickly get knackered at track days. Heavy cars can destroy a left front in a day. R-compounds don't suffer this. This is a paradox because if you used R-compounds on the road, they would wear out very quickly.
I use Dunlop Formula-R's on my E30 M3 on the track. They have a stiff side wall, so you don't over-inflate them, there's no need. They grip very well and they make the behaviour of the car more progressive and predictable.
Buying a set of R-compound tyres and a second set of wheels will save you money in the long term and put a smile on your face.

[GreenV8S]

Interesting, is that on the basis that normal road tyres will slide around but you don't slide as much on the softer tyres? (I generally keep the tyres just at the point of sliding rather than laying rubber on the track, and don't suffer much tyre wear or overheating on track days.)

[johnny senna]

GreenV8S said:

Interesting, is that on the basis that normal road tyres will slide around but you don't slide as much on the softer tyres? (I generally keep the tyres just at the point of sliding rather than laying rubber on the track, and don't suffer much tyre wear or overheating on track days.)

I'm not sure exactly, but everyone in our gang (we all drive E30 M3's at the track) has had similar experiences. I think it is because the R-compound tyres are designed for track use. I guess they slide less and so don't wear out so fast. Don't mistake not sliding for having less fun. The confidence these tyres inspire is huge. You ATTACK corners. Awesome. I've been on the same set of Formula-R's for ages. They seem to last really well. When I used my Bridgestone SO2 road tyres at Donington, I reckon I lost 3 or 4 mm on the front left. And I don't think I slide the thing overly either.

[Melv]

OK, the Melv method for achieving optimum 30-32psi HOT on a 911......is to check the COLD pressures after a track day (usually about 24psi) and then leave it at that and let the tyres warm UP to 32psi. They then stabilise at this for the day.

2psi over on the rears, i.e. 34psi hot, and I can feel the car moving about more.....

Melv

[joust]

I leave them just where they are on the Noble, on the advice of Lee Noble himself

Guess some cars are just "born" to track

Seriously, having left them at the factory recommendation and tracked the car hard a few times the middle of the rears are wearing slightly quicker than the outside, and hence seem to be just about right for me.

J

[cptsideways]

Once on a circuit your tyres will heat up, from scrubbing yes, but mostly from the brakes dissipating vast amounts of heat into the wheels (see how hot they get!) this raises the tyre pressures by quite a lot & why they stay hot for a long time. Hence once they are hot you then check & adjust them.

Don't however do this (a hot check) for road use as when they cool down you'll have no pressure. Unless you live in milton keynes & drive like a loon always, with all those roundabouts...

If you kept your tyres at road pressures on a circuit, and they've overheated you've probably worn out the centre area. Back on the road this'll be dodgy till you wear em even again.

Rules are: Warm up laps, hot pressure test set at normalish or slightly higher pressures, take a foot pump to go home on & let the tyres cool down before you test & drive home.

[fergus]

The heat sink from the brakes will have minimal effect on the heat of the tyre carcass. Granted the wheels will heat up through heat sink and this may raise the pressure slightly in the tyre, but the actions of accelerating and braking tends to heat the tyres better as they are then being used to generate grip in this mode rather than just rolling along.

Or use tyre warmers.... more of a bike trick though, unless you've got built in air jacks that is.

>> Edited by fergus on Friday 24th October 18:11

[kylie]

Hey thanks everyone! Loads of great advice. I put Toyo RA-1's on the other day and trying to sort the pressures cold and hot. I borrowed a infra-red gun from the lab at work and figured my tires needed to be set at 31psi cold, after hard driving round corners the pressures and temps were measured ASAP. They were sitting at 36psi and the temps were even across the tyre. I was instructed to inflat them by the supplier to 36psi cold but after testing them as above found I had to release loads of air out. SO hoping that this theory of even temps across the tire works. My biggest problem being the sidewalls quite tall and hope they don't move around too much on the rim with pressures being low for race tires. Otherwise they grip like mad.