If a car has a spare wheel included, then it’s probably not identical to the four wheels already attached to it. Some cars, especially most found in today’s new car market, will feature what is called a 'space saver'.
While space saver wheels bring practical and economy benefits (owing to their lighter weight), there are also certain legal and safety limitations which drivers should be aware of before fitting one to their car. If you want advice on changing a damaged tyre you can read our separate guide on how to do so.
A space saver wheel is meant to be fitted to a car if one of the standard tyres is either damaged or punctured. In this emergency scenario, you’ll want to get your car to a garage or back home as soon as you can to get the replaced tyre fixed or replaced.
Space saver tyres can either be full-size or smaller than the regular tyres fitted to your car. Because space saver tyres are usually left in the boot of a car, some manufacturers prefer having a smaller space saver to minimise the impact on boot capacity.
Whether or not it is full-size, a space saver wheel offers less tread depth and grip than a regular tyre. They are only meant to be used at slow speeds in emergency situations. In an MOT test which assesses a car’s suitability for the road, a car will always fail if not all the wheels are the same size, unless a spare wheel has been fitted temporarily purely in an emergency.
How to drive while using a space saver wheel
There’s no maximum limit established for how long you should drive on a space saver wheel, but the smartest and safest approach is to only use it on your car for essential trips.
Usually a space saver wheel will have a sticker printed on its side which will state the maximum speed you can safely travel while using it. Usually its safest to not travel over 50mph, but some space saver wheel stickers might give a lower figure.
If you can’t find a speed sticker on your space saver, try to keep your speed at 30mph or less. If you go over the recommended speed, then the space saver will wear quickly, could potentially overheat and will reduce the stability of the vehicle, so you could lose control of the car.
Even when you’re moving along at a recommended pace, your car will still offer significantly less grip with a space saver wheel than it does with four regular tyres. Approach every corner with extra caution and begin slowing down earlier than usual when approaching a red light or junction.
Take your time when you need to turn into somewhere and don’t be bothered by any impatient motorists surround you. Even more caution in general will be needed if the roads aren’t dry.
If you’re towing a trailer or caravan then using a space saver temporarily at low speeds can be acceptable, but check your owner’s handbook for your vehicle to see if there’s any vehicle-specific advice on this matter.