Going spare over a flat tyre

Holden has removed the spare wheel completely from the boot of the new Commodore sedan -- even the skinny space saver temporary tyre is no more. Instead, Australia's biggest-selling car -- designed and built for the harsh conditions of our wide brown land -- comes standard with puncture repair fluid and an inflator kit.

All this has been done to save between 20-25kg from a full-size spare wheel and tyre (the weight varies depending on the size of the wheel), which allows the Commodore to be tested at a lighter nominated weight in the fuel rating label tests.

The result of this is potentially a saving of 0.2L/100km on the fuel rating sticker on the windscreen, even though in the real world there would likely be little difference.

Holden defends the move and says it is giving customers the choice. The company says a full-size spare wheel and tyre has been optional since late last year and that 90 per cent of customers ticked the box to include a proper spare tyre with their car at no extra charge.

Given the popularity, why then not make full size spare tyres standard on all models? Presumably because the Federal Government's Green Vehicle Guide fuel rating figures -- done in laboratory conditions as opposed to real-world testing, as per the industry norm -- would be less flattering.

"We want to give drivers the choice," says the head of Holden engineering, Greg Tyus.

"Why should all drivers be penalised by a full size spare? It takes more energy to move something that's heavy than to move something that's light. It's simple physics."

Tyus admitted the question is whether the difference is perceivable to the motorist when comparing a 20kg saving in an 1800kg car. He also admitted that his company car has a full-size spare tyre, but he would feel comfortable without one.

"We spent more time debating this than you guys [the media] have," he said. "In my opinion, Australia is the only country in the world where there is this much emotion about this issue," the former Detroiter told the Carsales Network.

"A tyre inflator kit will fix 90 per cent of punctures. We've had no customer backlash. The customer has the choice. A full size spare is a no-cost option."

Tyre inflator 'goo' is useful to plug nail punctures in the tread of a tyre but is of little help when attempting to repair a split sidewall, which can occur when you strike a sharp pothole. Tyre experts state that once a tyre has been filled with inflator fluid it may need to be replaced.

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