track time tyre pressures.

[SGHOM]

I will bring along my 12V tyre inflater to japfest, so If any of you want to increase the tyre pressure for the track, feel free to use It. It might help though, If someone has an accurate pressure gauge ??? not sure how accurate mine is ? :)

[Grinder]

I thought you had to let tyres down for track work, as the prolonged extreme use makes them heat up increasing the pressure anyway.

Best to warm them up on the practice laps, test the pressure. If increased then let them down to good working pressure.

The Tyre Inflator is still essential, though, to pump up for the ride home!

[Nick Mann]

This argument has occurred before. Most say higher pressure for circuit driving, lower for dragging. Some disagree.

I'm sure people will point out their view!

I have a tyre pressure gauge that claims to be accurate to 0.5 psi. Any advances?

[Grinder]

I can see why you would reduce pressure on a quarter-mile - to increase grip for take-off.

But I am pretty sure :$ if you increase PSI before driving the track, and the tyres heat up due to extreme use, it will be over-inflated. At best you will have less of the width of the tyre on the road which will reduce grip, but if the tyre overheats and starts to break up how r u going to get home!

Here's the other discussion you mentioned - it makes a good case for increasing:

http://www.clubvr4.co.uk/forum/showthread.php?t=2914

Pros and cons I guess!

[Nick Mann]

Thats the thread. Well found!

My tyres reckon they're good for 50 psi. I have heard that under extreme conditions your tyre pressure can increase by 10 psi from cold. Therefore a cold pressure of 40 psi will never exceed the design parameters of the tyre? Not saying that it won't wear out a bit quick, though!

I'm not on the track on sat, so I would like everybody who is to take my ramblings with a pinch of salt!

[wirdy]

Increase your pressures a bit for the track.

You risk the bead seal breaking or, at worst, the tyre rolling off the rim under extreme provocation otherwise.

The increased wear on the centre of the tread will be equally offset by the wear on the sidewalls under 'enthusiastic' cornering. :-D

[lorriman]

Got one of those battery operated tyre gauges and it claims to be accurate to within 0.1%. Strange that as it only reads to the nearest 1psi. A lot of use when the tyre pressure info on my car is in bars. Had to get the calculator out the first time to do the conversion. Why can't they just say 32 and 30psi?

Anyway my gauge is left in the car permanently if anyone wants it on Saturday. I've gotta contribute something.

[Polabear]

Will have my 12v compressor as well, also good old trusty dunlop tyre guage :-b