Tire Safety
Please use the following information for your personal vehicles as well as your State vehicles. 

How often should I rotate my tires?

Have your tires rotated when you get your oil changes done every 5,000 miles.  During this rotation and PM service, have the technician look for leaks, check the suspension, undercarriage and exhaust system.

An unbalanced wheel and tire assembly may create an annoying vibration when you drive on a smooth road and may result in irregular tread wear. If you notice “cupping” wear on the tires, have the balance checked.

Misalignment of the wheels, improperly operating brakes or shocks, bent wheels, worn bushings and other mechanical problems cause uneven and rapid tread wear and should be corrected.  Have these systems checked periodically.

How much air should I put in my tires?

The right amount of air pressure is specified by each vehicle manufacturer for the front and rear tires on your particular vehicle. 

The correct air pressure is shown on the tire placard attached to the vehicle door edge, door post, glove box door or fuel door. 

If your vehicle doesn’t have a placard, check the owner’s manual or consult the vehicle manufacturer or the Motor Pool. 

How do I check the air pressure?

Use an accurate tire pressure gauge to determine your tire pressure.  Air meters at service stations may be inaccurate due to exposure and abuse.

Check tire inflation pressure, including the spare, at least once a month and before every long trip.  Tires must be checked when they are cold, that is, before they have been run a mile.  If you must drive over one mile for air, measure the cold inflation pressure of each tire and record the actual under-inflation amount for each tire.  When you arrive at the service station, measure each tire again and then inflate the warm tire to the level that is equal to this warm pressure plus the cold under-inflation amount.

Why do my tire pressures fluctuate?

Tires lose air normally through the process of permeation.  Changes in outdoor temperature can affect the rate at which your tires lose air.  This change is more pronounced in hot weather.  A tire may lose one or two pounds of air per month in cool weather and even more in warmer weather.   Gradual air loss will increase the tire’s operating temperature.  This can cause some of the components to separate, or damage the tire body in ways that create rapid or sudden air loss.  Do not bleed air pressure when tires are hot.  It is normal for pressure to build up as a result of driving.

Why is proper tire pressure so important?

Under-inflation or overloading tires creates excessive heat and can lead to tire failure, which could result in vehicle damage and/or serious injury or death.  Proper inflation extends the life of the tire and saves fuel. 

Uneven wear patterns may be caused by improper inflation, misalignment, improper balance or suspension neglect.  If not corrected, further tire damage will occur.

Never reduce tire pressure in an attempt to increase traction on snow or ice.  It does not work and driving with your tires under-inflated will damage them.  If a tire has received a severe impact, such as hitting a curb or pothole, have it removed from the wheel and inspected both inside and out for impact damage.  An impact-damaged tire may appear serviceable on the outside, but can fail later.

How often should I replace my tires?

Certain uneven wear patterns may indicate that the tire has suffered internal structural damage and requires attention.  When the tread is worn down to one-sixteenth of an inch, the tires must be replaced.  Built-in tread wear indicators, or “wear bars” which look like narrow strips of smooth rubber across the tread, will appear on the tire when that point of wear is reached.  When you see these wear bars, the tire is worn out and it’s time to replace it.  If your job requires you to do a lot of off-road travel, such as dirt roads and trails, check your tires more often.  Damages can and do occur more often when exposed to rough terrain.

Always replace a tire with another tire of exactly the same bead diameter designation and suffix letters.  Never choose a smaller size or with less load-carrying capacity than is recommended by the automobile manufacturer.  Always have tires mounted with the same size and construction designations on the same axle, unless otherwise recommended by the manufacturer.

Example - a 16" tire goes on a 16" rim.  Never have a 16" tire mounted on a 16.5" rim.  It is possible to pass a 16" diameter over the lip or flanges of a 16.5" rim, it cannot inflate enough to position itself against the rim flange.  If an attempt is made to seat the tire bead by inflating, the tire bead will break with explosive force and could cause serious injury or death.  Mounting and de-mounting tires should be left to skilled professionals.

Tire Safety Tips

Make sure all tire valves and extensions are equipped with valve caps with rubber gaskets to keep dirt and moisture out. 

Look for any stones, bits of glass, metal or other foreign objects wedged in the tread.  These may work deeper into the tire and cause air loss.  If any tire continually needs more air, have it taken off the vehicle and checked to find out why it is leaking.  Damage to the tire, wheel or valve may be the problem.

When you’re stuck, do not spin the tires.  The forces created by a rapidly spinning tire can cause an explosion by literally tearing the tire apart.  These forces impact the whole tire structure and can rupture the entire casing.  Some vehicles are capable of bringing a tire to this failing point in 3 to 5 seconds.  Avoid tire spinning, and never exceed 35 mph while spinning a tire.  Do not allow anyone to stand near or behind a spinning tire.

When stuck on ice, snow, mud or wet grass, the vehicle should be rocked gently back and forth by repeatedly shifting the gear lever from drive to reverse on automatic transmissions, or reverse to second on manual transmissions.  This should be done with the least amount of wheel spinning.  If that doesn’t free the vehicle, get a tow. If you don’t take proper care of your tires, the results can be serious.  Serious injury may result from tire failure due to under-inflation or overloading.  Follow the owner’s manual or tire placard.

Do not depend on tire aerosol sealants and inflators to fix a damaged tire.  Some aerosol products contain flammable gasses, such as butane or propane as propellants.  Follow the directions and precautions printed on the canister when using these products.  Be sure to inform the tire service personnel that you have used a flammable aerosol to inflate your tire.