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Full-size spare tyres are rare

Space saver tyre
Space saver tyre

We explain why full-size spare tyres are fast becoming exceptions rather than the norm.

While modern cars are more reliable than ever and our roads are in better shape, a flat tyre is an irksome reminder that some things never change. However, if you get a puncture today, your vehicle might not even have a 'conventional' spare wheel to fit.

Car manufacturers love to save weight, improve fuel consumption and reduce production costs. We first saw some European brands replace the weighty spare with a space saver back in the 1980s. Their use is widespread these days and even the new Euro-sourced Holden Commodore has a space saver spare.

There are four main categories of spare tyres: full-size, temporary use/space saver, run-flat tyres (RFTs) and inflator kits. Full-size is a direct replacement for the wheels fitted to your vehicle, although manufacturers are increasingly fitting replacement tyres onto a cheaper steel rim rather than an alloy wheel (if they're fitted to your vehicle).

Space savers have greater limitations than a full-size spare and are primarily designed to enable the vehicle to be driven to a repairer. In most cases, they're speed limited to 80km/h because they're a different size to your car's other wheels and can potentially upset handling and braking at high speeds.

Some vehicles don't have a spare wheel at all and are fitted with run-flat tyres. An RFT looks like a conventional tyre, but can run uninflated in the event of a puncture. Like the space saver, it has its limitations and should only be used up to a certain distance (usually 80km). A warning light alerts the driver to lower pressure in a tyre so it can be checked and inflated if necessary. One advantage of the RFT is you don't have to immediately stop on an unsafe stretch of road to change the tyre.

Inflator or mobility kits are the least preferable option. They incorporate either a battery-powered air compressor and tyre sealant, or pressurised containers of sealant. In effect, you become the tyre repairer, but inflator kits generally only work if the puncture is small and the tyre is undamaged. In some cases, the sealant makes the tyre unusable for a permanent repair, and the cost of replacing the sealant kit can run into hundreds of dollars. Another catch is they have a use-by date - so, even if you don't use it, the kit needs to be replaced over time.

For those commuting mostly in the city, a non-traditional spare is less likely to be an inconvenience. While a full-size spare lets you continue on with no concerns, trying to find a replacement tyre on a weekend in a smaller town can be difficult. If you're buying a new vehicle and you live in a regional area, make sure you're aware of its spare tyre type.

This article was originally published the May/June 2018 issue of the Open Road magazine.

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