One of the most neglected parts on the average automobile is going to be the spare tire. Nobody ever seems to check them, and that can put you in an embarrassing situation. You’ve got a flat tire on the car, you’ve got a flat spare. Now what do you do? Well, you should have checked the tire pressure in your spare once every month to make sure that it has the proper amount of air in it.

But that leads to a problem, because most cars today have temporary spares, and temporary spares require a lot more pressure than the conventional tires on the car. Now, because of that higher pressure reading, you may wind up needing two tire pressure gauges: one to read the high pressure in the spare, and one to read the lower pressure in the tires on the car. The one for the lower pressure, it can’t read the high pressure, and the one that reads the high pressure, it is not accurate enough for the lower pressures on the car. Now in some cases you might get by using one of these more expensive but highly accurate dial type gauges.

All right, so tire pressure is important, but there’s a lot of other information that is embossed into the side of the temporary spare. It tells you how fast you can go with it. It also tells you how far you can go with it in many cases. Now I understand that you may think that this only has to do with wearing out your temporary spare, but that couldn’t be farther from the truth.

You see, when you use a temporary spare on the drive axles of the vehicle, you have one tire that is larger than the other. Now this sets in motion some gears inside the differential of your car that normally only spin when you’re going around corners. So now you are spinning those all the time, and by going a longer distance or a higher speed than what’s recommended on the tire, well, the tire may survive just fine, but you may do a lot of damage to the differential in your car.

See, in 200 miles with a temporary spare, you could potentially produce the wear of about 20,000 miles of normal driving with conventional tires. So read and follow the directions on your temporary spare. It is not in your best interest to disregard them.

If you have a question or comment, write to me.  The address is MotorWeek, Owings Mills, MD, 21117.