Why Are Some Spare Tires Smaller Than Normal Tires?

Depending on your car, you may find that the spare tire you've been provided with is smaller than the rest of your tires. These are more popularly called 'donut' spare tires. So why does your car have these skinny, fragile-looking tires while clearly, other vehicles have spares that come as the same size as what’s installed? There are three reasons for this:

It saves space

The main reason your spare tire is smaller is because they are meant to take up less space in your vehicle. Donut spares usually have a smaller diameter, narrower width and shallower tread, which means they make great space-savers. This is especially important to maximize the storage area in your boot.

It makes the car lighter

Donut tires are generally made of lightweight material, and this results in a lighter car overall. Full-size tires add to the vehicle’s total weight, which can have a negative effect on gas mileage, and the bigger the tire, the more noticeable this negative effect will be.

It lowers the price tag of the vehicle

Needless to say, a simpler and lighter spare tire costs less to produce than a full-sized one, and this difference is reflected in the vehicle’s price.

Key points to remember about donut tires

It's important not to keep driving on a donut tire for an extended period, as the size difference could eventually impact alignment and handling. Additionally, the tire itself is not built to last—it is only meant to allow you to get your car to a tire repair facility safely, so keeping on using it is ill-advised. Once you get a flat, make sure to have your regular tire repaired and re-installed as fast as you can.