Q. BB from Wicklow asks: Why are full-size spare wheels so expensive? I have an EV Niro 223. Rim size 7Jx17 ET52. Specific size to fit rear calipers. Quoted almost €1,000 with specific EV tyre. A hidden cost for EVs.
A. To be fair to electric cars, a full-size spare is something of a hidden cost for almost every new car now, regardless of whether it’s powered by a battery or a liquid fuel.
The full-size spare started to disappear in the 1990s, in favour of the “space saver” – a narrower, smaller wheel and tyre which, when fitted to the car, limits your top speed to 80km/h (because the smaller tyre can’t dissipate heat so easily) but which saves a considerable amount of boot volume, making cars more practical in a day-to-day sense.
Even space savers started to disappear once we got to this century, as car makers became ever keener to save not only space but weight, not least because alloy wheels were becoming bigger and bigger as cars grew in size and designers didn’t want them to look as if they were running around on sofa castors. Think back to the late 1980s, and a large family car such as a Ford Sierra would have come with 13-inch wheels fitted to the base model, and even the famed Sierra Cosworth ran on 15-inch rims.
Fast forward to today and an average family car often comes, in its most basic form, with a 17-inch wheel, and 18- to 19-inch diameters are quite common. Even 20-inch rims, once the preserve of high-performance and luxury models, are now being offered as optional extras for relatively humble cars.
With size comes weight. A 17-inch alloy wheel, in spite of protestations about lightness (alloys often weigh more than a comparable pressed steel wheel) can weigh 20kg or more, and then the full-size tyre weighs another 10-15kg on top of that. To improve the official fuel consumption of vehicles – and latterly their CO2 performance – manufacturers started deleting full-size spares, and then space savers too, to save the vital handful of kilos which could mean the difference between jumping a tax band or not.
With electric cars, the problem is exacerbated. Not only do they need lots of lowdown space for packaging batteries, motors, and electronic control systems (all of which are bulkier than you might think), weight is a crucial factor in determining a car’s official WLTP range. So, as far as the car maker is concerned, losing about 35kg in the spare and its tyre in favour of maybe a 1kg air compressor and a can of tyre sealant is a no-brainier.
For the final owner, of course, it’s a potentially different story. The squirt-and-inflate routine works well if your tyre has been punctured by a nail or screw for example, but won’t work at all if you’ve clouted an unsighted pothole or some other obstacle on the road. Roadside recovery services such as the AA and mobile tyre repair services can help, of course, but they won’t necessarily be able to provide you with the right-size tyre on the spot.
There are solutions, however. If you’re prepared to accept the loss of boot space, wheels and tyres can be more affordable bought from aftermarket sources, and if you need to replace the boot floor to accommodate the bulkier shape of the full-size spare, those can also be bought from third-party sources, and are easy enough to fit at home.
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There is another simple solution – run-flat tyres. These can allow you to drive home on a flat tyre thanks to a beefed-up sidewall. Yes, you’ll be restricted to 80km/h and yes you need to get the tyre replaced as soon as possible, but they can be a lifesaver in emergencies, obviate the need for a spare, and aren’t much more expensive than a conventional tyre. They also don’t affect the ride quality of cars as disastrously as they did when first widely introduced in the early 2000s. Check with your car’s manufacturer to make sure that run-flat tyres are compatible before fitting, of course.
