Commodore to drop spare tyre
Toby Hagon, drive.com.au, August 15, 2008


Holden is re-engineering the Commodore to give it the performance of a V6 and fuel economy of a four-cylinder.


Holden is looking at removing the spare tyre from the Commodore and instead fitting controversial run-flat tyres as part of a broader plan to improve fuel efficiency by more than 20 per cent and reduce carbon dioxide emissions.

General Motors Holden chairman and managing director Mark Reuss says the imminent move to tyres that can be driven on after a puncture is designed to reduce weight, helping the V6 Commodore the efficiency of a four-cylinder.

Reuss believes getting the basics of the Commodore design right is more important than relatively expensive additions such as a hybrid powertrain, which he is now hinting will not happen as early as 2010. This is in contrast to General Motors group vice president Nick Reilly, who said hybrid Commodores would arrive in “a couple of years”.

“There’s a lot of things we can do in the near term and a lot of things we can do in the further term … there’s a lot more to go (in terms of efficiency improvements),” says Reuss, citing everything from weight reduction to more efficient tyres, engine improvements and better aerodynamics.

“It would be really stupid to make a sequential decision around a hybrid in a Commodore before we have efficiency in the base architecture done. I’m talking about all the pieces to get an efficient platform.”

Reuss believes the fuel economy of a regular, petrol engine Commodore can be reduced by 20 per cent or more. He says today’s official average fuel consumption figure of 10.8 litres per 100km could drop to 8.5L/100km.

That would make the entry-level Commodore as efficient as many of today’s smaller, mid-sized four-cylinder cars. A Mazda 6 uses a claimed 8.4 litres of fuel per 100km while a Toyota Camry uses 9.9L/100km.

“We want to give what’s important to the customers, which is the operating efficiency of a small car in a large car.”

Key to the Commodore’s fuel efficiency and CO2 reductions – which Reuss cites as “a very high priority” - is stripping weight.
“If we have a mindset that we have to go after every gram the opportunity there is quite large,” says Reuss. “Mass begets mass, so the bigger the car is, the more massive the car is, the bigger the brakes are, the more you have to press the throttle. It just goes on and on.” (Sound familiar?-crYnOid)

Reuss says the removal of a spare tyre (and jack, tools, etc) as a great way to save up to 16kg of weight.

“There’s plenty of things in the industry, like a Honda Odyssey mini van in the US, that uses a run-flat tyre,” says Reuss. “The technology is there, but we have to make sure the technology of a run-flat tyre is applicable to the car you’re putting it in.”

Reuss is acutely aware of the controversy surrounding cars fitted with run-flat tyres.

The pioneer of the technology locally, BMW, staunchly defends run-flat tyres as being safer and more convenient if you do get a puncture. Opponents have criticised the higher costs (no longer an issue), compromises in ride quality and change in driving dynamics if you do get a puncture.

Reuss plans to circumvent those concerns by giving buyers the choice between regular tyres (including a spare) and runflat tyres.

“[We’ll] make it a free option and tell the customer how much fuel they’re going to save by not carrying it around in the city,” he says. “As long as we option it at no cost then who cares? If [a spare tyre] is what you want and you’ve got to have it then great, but don’t penalise everybody [by adding weight].”

Reuss also says the increased use of lighter materials, such as aluminium, is also being considered.

“How do you measure the cost of lost sales due to fuel economy and mass?” he asks. “What it gets down to is you want to have a rule with everything you look at in a car on a cost per kilogram basis. [This is a] rule of thumb you apply to every single piece of the car”

He also says Holden’s large car could get a smaller V6 engine – the current V6 family can be built in sizes from 2.8 litres to 3.6 - and has not ruled out the option of the return of the four-cylinder Commodore.

“If you look at technologies like direct injection you can decrease the engine size and actually increase the power and increase fuel economy,” says Reuss. “The performance of the Commodore could be equal to or better than today if we can achieve both fuel technology, engine technology and mass efficiency and vehicle efficiency.”

The Commodore’s hydraulic power steering is also set to be replaced by a more efficient electric system.

The Commodore is also undergoing a complex analysis of its aerodynamics. Reuss plans to put the Commodore in a wind tunnel to verify proposed changes, which could encompass underbody updates, adjusted ride heights and revised tyre designs.

Reuss says the improvements to the Commodore will be rolled out progressively over the next few years, rather than in one big project. The first updates are due by the end of the year.

“Over the next three years you’re going to see a new entry, a new technology or both over the next couple of months.”

Holden and its parent General Motors are embarking on a strategy to diversify the fuel options that can be used in its vehicles. It is working on everything from electric and hydrogen power to natural gas, LPG and ethanol.