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Oregon Tire Regulations


Proper inflation pressure—perhaps the most important tire condition to monitor—gives tires the ability to support the vehicle and you to control it for maximum performance. Bonus benefit: Maintaining proper inflation pressure maximizes fuel economy, too.

  • Under-inflated tires generate excessive heat build-up and stress, causing irregular wear and internal damage.
  • Over-inflated tires are more likely to be cut, punctured or damaged when hitting an obstacle, such as a pothole.


Use a tire gauge to check inflation pressure, measured in in PSI (pounds per square inch). You’ll find recommended pressure on a label on the driver’s door or in your vehicle owner's manual.


Tire Pressure Monitoring Systems (TPMS) detect loss of inflation pressure and warn drivers when tires are 25% under inflated. For many vehicles, this warning may be too late to prevent damage. TPMS are not a replacement for monthly tire pressure checks with a gauge.


Tread equals traction—giving your tires a grip on the road, especially in bad weather. Lose too much tread and you could lose control.

Once your tread wears down to 2/32nds of an inch, it’s time to visit your local tire shop. Take a few minutes each month to visually inspect your tires for uneven wear, high and low areas, unusually smooth areas and other signs of damage.

Tires have built-in tread wear indicators, or wear bars. When the tops of these bars are flush with the tire’s tread, the tire needs to be replaced.

Replacing Tires

When it’s time to replace the tires on your vehicle, don’t guess. Consult the proper sources to determine exactly what you need.

Fortunately, your tire specifications travel with you—usually on a label inside the driver’s door, in the glove box or in the fuel door. Your owner’s manual should also have the right information. If you still have questions, just ask your local tire professional.

In the meantime, keep these basic tire replacement requirements in mind:

Your replacement tires should:

  • Be the same size, load index and speed rating designation as recommended by the vehicle or tire manufacturer.
  • Not be of a smaller size or load-carrying capacity than what was originally specified. That could be dangerous.

Replacing Fewer than Four Tires

USTMA recommends replacing all four tires at the same time for optimal performance. If this is not feasible, you should follow these guidelines for replacing fewer than four tires:

  • Whether you replace only one or two tires, be sure that they are the same size, load index and speed rating recommended by the vehicle manufacturer.
  • If replacing only two, install them on the rear axle. The newer tires will have better grip, particularly on wet roads, which is important to avoid hydroplaning situations. The greater traction capability on the rear axle can better prevent a possible oversteer condition and loss of vehicle stability.
  • Replacing a single tire can negatively affect vehicle suspension, transmission and tire treadwear. If unavoidable, pair the single replacement tire with the tire that has the deepest tread depth and install both on the rear axle.

Tire chains are required when conditions demand because of snow, ice or other inclement weather and SNOW ZONE signs are posted. When signs are posted, you must use chains on any single drive axle vehicle rated over 10,000 pounds gross vehicle weight (GVW) and you must use chains if your vehicle is towing (such as a pickup towing a boat). Chains must also be used on the trailer or vehicle being towed. Under this condition, chains are not required on tandem drive axle vehicles. For chain information from within Oregon, call 511 or 1-800-977-ODOT (6368). From outside Oregon, dial 503-588-2941. Drivers who disobey the signs requiring chains or traction tires are subject to a traffic infraction, $190 for failure to obey snow zone signs and $544 for failure of a commercial vehicle to use chains. For more information, go to ODOT’s Web site at Also for minimum chain requirements

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