A puncture! Tire loses pressure, and soon you are unable to continue your journey - or you would be without a spare tire. Most people use the so-called donuts to save on space, but do not forget - these will not last long.
How far can you drive on a spare tire? Short answer – it depends. Long answer – from just a few dozen miles to another tire’s lifetime. In general, there are three types of spare tires to talk about: space-savers, full-sized spares and run-flat tires.
In the past, you could often mount a spare tire somewhere on the vehicle or put in the tire well. Today, you will find that except some SUVs or off-road vehicles, you are forced to store the spare tire in the trunk. For this reason, space savers, or donuts, are commonly used now, as they take much less space in the trunk than a full-sized tire. They are also appreciated because they are lighter, and therefore require less effort to replace.
Space-savers, however, have a very limited durability. The idea behind them is to get you to a tire shop to repair or replace your flat tire. How long can you drive on a spare tire? The exact distance you can use them for will vary between 50 and 70 miles. Most of them also have a speed limit of 55 mph. They are not intended to be driven on for longer distances. Having only one layer of polyester in a sidewall and two belts of steel and a layer of polyester beneath the tread, donuts are much less durable and using them for longer distances increases the risk of a blowout. They should be driven with care, too, as they will handle quite differently due to very little tread they have, their narrower design and the reduced contact area. Handling, cornering and braking will be noticeably worse with a donut.
Always remember to carry an identical full-sized spare tire. If you are preparing for winter and want to use snow tires, do not forget to change the spare tire too.
Full-sized spares are much stronger that the space-savers. They are heavier and unfortunately take up the most space in the trunk, but carrying them may be rewarding. Such tires can be included in the standard rotation pattern to ensure the tread is slightly worn so as to achieve performance to tires that are currently in use. They can be driven on until they age out or wear down like any normal tire, which gives you more time to get another spare tire.
Run-on-flat system tires
Tires equipped with one of many Run-on-Flat (RoF) systems are also an option. There is a number of quite different technologies used these days. Runflats are essentially tires that upon puncture will turn into temporary spares. Make sure that your TMPS sensors are working properly – they are so rigid that you may not notice that you are running on a depressurized tire. After the pressure is lost, these tires will still carry you on their stiff construction over a very limited distance with a very limited speed to a nearest tire shop without having to change the tire on the way. The disadvantage is that they can be quite expensive and their availability may sometimes be a problem. Mounting run on flat tires requires special rims and equipment, which may not be available in every auto service. They also cannot be patched – once punctured, they have to replaced.
Which one to go for
All in all, if you can afford to take a full-sized spare with you, go this way. It takes space in the trunk, but if one of your tires get punctured, you can replace it with a tire that can be used for much more than fifty miles. The damaged one may then still be repaired and stored as the new spare. Otherwise – it seems that car manufacturers do not give us much choice. Since there is no place to mount the spare to, we have to live with having to rely on space-savers.