Tyres under pressure

  • Virgin Australia Supercars Championship
  • |
  • 13/08/2014
  • By V8 Supercars

Official V8 Supercars supplier Dunlop would support the introduction of tyre pressure sensors on the basis that it would lead to less failures and improve the racing.

While the recommended minimum pressure for the Dunlop Sport Maxx control tyre is 18psi, it is thought some teams have experimented with settings down into single figures, primarily to extend the life of the sprint (soft) tyre.

But the low pressures also place extra stress on both hard and soft tyres, which can lead to punctures, especially when combined with aggressive camber settings and sharp kerbs.

In the case of the soft tyre, the introduction of tyre pressure sensors would allow a minimum pressure to be mandated ensuring it 'fell off the cliff', meaning its lap time ability would be dramatically reduced after 80km.

"The soft tyre originally was only designed to do 80km and people are stretching it to 110, 120, 130km," Dunlop V8 Supercars operations manager Kevin Fitzsimons told v8supercars.com.au.

"If everybody has got the same pressures then it may improve the show because then you have the tyres dropping off rather than staying good to the end of the race.

"If we could mandate a minimum pressure then everyone would have the same and then we send them out and see how we go."

The subject of mandatory tyre pressure sensors has been discussed by the V8 Supercars Commission, but the cost of the system's introduction is understood to have become a significant debating point.

The dollars are substantial when you consider each car has a stockpile of around 40 wheels and a sensor must be fitted to each of them.

"I think it is an unnecessary suggestion for the category," said Ford Performance Racing ace driver Mark Winterbottom's engineer Grant McPherson. "This sport is already too costly and across the category this would be an incredibly costly exercise."

V8 Supercars Director of Sport and Operations Damien White, who is also on the V8 Supercars Commission said: "There has been discussion on a tyre pressure monitoring system, and while there may be benefits to such a system, the cost remains a concern.

"We need to consider if there is a workable low cost option. For example, mandating a minimum pressure and checking for compliance with random checks may work.

"It requires more discussion, however at the moment we don't weigh the cars every time they come in pit lane. And as with car weight I imagine the teams would have to do a risk versus benefit analysis of low pressures and my view is they wouldn't chance a penalty by running anything under a regulated pressure."

Fitzsimons explained that at 18psi - which he concedes is a conservative figure - the middle of the sprint tyre is crowned and therefore wears through at the expected rate. But the lower the pressure, the flatter the footprint and the more even the wear.

However, the lower pressures also put more pressure on the sidewall, which is what generates the failures.

"Basically, with the sidewall squashed it changes the profile of the tyre to put more rubber on the road and tries to help take the load off the centre of the tyre," he said.

"It puts massive load on the sidewall at the joint between the steel belt and the sidewall and that's where the failures creep in."

FPR has clearly got a handle on the tyre pressure and longevity issue, winning 200km Super Sprints at Winton, Barbagallo and Darwin on softs, as well as the hard tyre mini-marathon at Pukekohe.

However, Winterbottom's chances of a good result in Race 25 at the Coates Hire Ipswich 400 were foiled by a tyre failure. Teammate David Reynolds in the Bottle-O Ford Falcon FG II also suffered a tyre failure in the Sunday race. Both punctures were blamed on damage inflicted by kerbs.

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