Modern spare tires are usually a lot smaller and constructed differently than the other tires on your car. That's because today's spares are only built for temporary use and are made to save as much space as possible. Temporary spares should only be driven on as long as it takes to get to a garage or tire store to have your tire fixed or replaced. Temporary spares may be dangerous at high speeds are much less durable than your car's regular tires. Most manufacturers recommend not going over fifty miles an hour on a temporary spare. In addition to being smaller than your regular tire, they're also thinner, which means you could have handling problems at increased speeds. It might be a good idea to check your spare's pressure once in a while since it usually needs higher air pressure than other tires. Consult your car's owner's manual for more information on proper use of the temporary spare.