To get the most out of your tires—maximum mileage, safety and wear—you’ll need to properly maintain them. But don’t worry. It’s not as complicated as it sounds, and we’re here to help.
Reading A Tire Sidewall
A tire’s sidewall is simply the outer and inner “walls” on the sides of a tire, if facing a tire on its side. Every sidewall has its own unique information that is divided into three main sections:
1. Tire Specs
This describes the fundamental characteristics of your tire. Size, construction, speed rating and more.
2. Department of Transportation Safety Code
This assures that your tire complies with all Department of Transportation (DOT) safety standards. After the DOT insignia is your tire’s identification number, which begins with the tire’s manufacturer and plant code where the tire was manufactured (two numbers or letters). The ninth and tenth characters tell the week the tire was manufactured. The final number(s) signifies the year the tire was manufactured.
3. UTQG Code
The Uniform Tire Quality Grading (UTQG) was established by the National Highway Traffic Safety Administration (NHTSA) to test tires following government prescribed test methods and then grade each tire on three main components:
Treadwear: This is the wear rate of the tire, comparable only to other tires within a tire manufacturer’s line. 100 is the baseline grade. Therefore a tire with 200 would theoretically last twice as long on the government’s course compared to a tire with 100.
Traction: Traction grades are AA, A, B and C (with AA being the highest grade). They represent the tire’s ability to stop straight on wet pavement as measure on a specified government track. Any tire rated under C is considered unacceptable for road travel.
Temperature: The temperature grades, from highest to lowest, are A, B and C. These represent the tire’s ability to dissipate heat under controlled indoor test conditions. Any tire rated below C is considered unacceptable.
Some tires have unique benefits, as showcased with specific icons. For example, the MICHELIN® Green X® Marking is a guarantee that the tire provides a level of energy efficiency among the highest in the market for its category without compromising traction and treadwear. The letters M and S (M +S) indicate that the tire meets the Rubber Manufacturers Association’s standards for a mud and snow tire. The letters can be found in the following combinations: M+S, M/S, and M&S. All-season tires carry this mark.
How to Check Tire Pressure
Tires have been known to lose up to 1psi (pounds per square inch) every month, so check all tires, including your spare, once a month (or before a long trip). It’s easy. Here’s how:
- Purchase a trusted pressure gauge.
- Check your tires “cold” – before you’ve driven or at least three hours after you’ve driven.
- Insert pressure gauge into the valve stem on your tire. (The gauge will “pop” out and show a measured number. When you hear a “pssst” sound, that’s air escaping the tire. The escaping air shouldn’t affect pressure substantially, unless you hold down the air pressure gauge too long.)
- Compare the measured psi to the psi found on the sticker inside the driver’s door of your vehicle or in owner’s manual. DO NOT compare to the psi on your tire’s sidewall.
- If your psi is above the number, let air out until it matches. If below, add air (or have a Michelin retailer help you) until it reaches the proper number.
Nitrogen Versus Compressed Air
Most tires are filled with compressed air. But some tire retailers have started to put nitrogen into their customers’ tires. (Nitrogen is simply dry air with the oxygen removed. Air contains nearly 79% nitrogen already.) Because nitrogen replaces oxygen, less air can escape your tires, and your inflation pressure stays higher longer. Unfortunately, there are other possible sources of leaks (tire/rim interface, valve, valve/rim interface and the wheel) which prevent the guarantee of pressure maintenance for individuals using air or nitrogen inflation.
Nitrogen and compressed air CAN be mixed, if needed. Tires manufactured by Michelin are designed to deliver their expected performance when inflated with air or nitrogen, as long as the user respects the pressures recommended by the vehicle manufacturer on the vehicle’s placard or by the tire manufacturer.
How To Inspect a Tire
Once every month, or before you embark upon long road trips, check your tires for wear and damage problems. One easy way to check for wear is by using the penny test. All you have to do is grab your spare change and follow 3 easy steps.
- Take a penny and hold Abe’s body between your thumb and forefinger.
- Select a point on your tire where tread appears the lowest and place Lincoln’s head into one of the grooves.
- If any part of Abe Lincoln’s head is covered by the tread, you’re driving with the legal and safe amount of tread. If your tread gets below that (approximately 2/32 of an inch), your car’s ability to grip the road in adverse conditions is greatly reduced.
To obtain maximum tread life, it is necessary to rotate your tires. Michelin
recommends rotating your tires every 6,000 to 8,000 miles (10,000 to
12,000 km), or as specified by your vehicle manufacturer, whichever
rotation period is less. Check your vehicle owner’s manual for any
recommendations by your vehicle manufacturer. Monthly inspection for
tire wear is recommended. Your tires should be rotated at the first sign of
irregular wear, even if it occurs before 6,000 miles (10,000 km). This is true
for all vehicles. When rotating tires with a directional tread pattern, observe
the arrows molded on the sidewall which show the direction the tire
should turn. Care must be taken to maintain the proper turning direction.
Some Tire Pressure Monitoring Systems (TPMS) may not recognize
that a tire has been moved to a different position on your vehicle.
Make certain that your TPMS system is reset, if necessary, so as to
correctly identify the location of each tire on your vehicle. Refer
to your vehicle owner’s manual or your vehicle dealer. Determine
whether rotated tires require tire inflation adjustment as front and rear
position tire pressure may vary according to the vehicle manufacturer’s
specification due to the actual load on that wheel position. Some vehicles
may have tires of different size mounted on the front versus the rear
axles, and these different tires have rotation restrictions. Always check the
vehicle owner’s manual for the proper rotation recommendations.
Tire balancing compensates for the weight of the tire and wheel assembly after the tire is mounted. A wheel is out of balance when one area is heavier or lighter than the rest. The result? Bouncing or wobbling, which can decrease treadwear, increase vibration and cause stress on your vehicle. The cure? Correction weights are added to counterbalance the tires.
When to Balance
- A tire is replaced
- A balance weight is moved or removed
- You purchase new tires
How Wheels are Balanced
To balance a wheel, your mechanic uses a balancing machine to determine where the heavy spots are. Weights are then attached to the exterior or interior of the wheel to counteract centrifugal forces acting on the heavy areas when the wheel is turning. This will eliminate vertical bouncing and side-to-side wobble.
Alignment refers to the adjustment of a vehicle’s front and rear suspension parts. If your alignment is off, your vehicle isn’t safe to drive. View the animation below to understand the three main adjustments made during alignment:
Caster is a bit tough to define. If you’re viewing the side of a vehicle, the caster angle identifies the forward or backward slope of a line drawn through the upper and lower steering pivot points. Think of a motorcycle and its front steering forks and front tire. Its angle is towards the rear of the motorcycle, so it has positive caster. Negative is just the opposite. Long story short, positive caster helps your vehicle go straight, much like the motorcycle.
Camber is the angle of the wheel, in degrees, when viewed from the front of the vehicle. Positive camber is when the top of the wheel is leaning out from the center of the car. Negative camber is when the top of the wheel is leaning into the car. If the wheel leans too far from the center, uneven wear will occur. (However, negative camber helps racing cars improve cornering.)
Toe is the difference in the distance between the front of the tires and the back of the tires. Usually, tires are set so that they are parallel with each other. If the fronts of the tires are closer, the wheels are toe-in. If the rears of the tires are closer, the wheels are toe-out.
When to Check Alignment
Daily impacts such as potholes and railroad crossings, as well as more severe circumstances like a car accident, can knock your vehicle out of alignment. You should have the alignment checked if:
- You’ve hit something substantial
- You see a wear pattern developing on the shoulders (outer edges) of the tires
- You notice a difference in your vehicle’s handling
Tire Care Products
Nothing makes a car look sweeter than a shiny set of tires. But don’t put your investment at risk by using just any cleaner. Make sure to only use non-petroleum based products to clean the tires. A number of wheel cleaners may contain harsh acids, alkalis and/or detergents that can damage wheels and paint. However, there are products out there that are safe for all brands of tires as well as environmentally responsible. You can find them at an auto parts dealer near you