Changing sizes or specs

Four-wheel drive vehicles

If no instructions for tire mixing appear in the vehicle owner’s manual, adhere to the following guidelines:

• Do not mix sizes. All four tires must be the same tire size.

• Do not mix radial and bias-ply tires. All four must be either radial or bias-ply.

• Be sure that the outside circumferences of all four tires are within 2,5 cm (1") of each other.

• Do not mix tread patterns, such as all-terrain and all-season.

Don’t mix radial and non-radial tires

• However, if mixing tires is unavoidable, the two radials must be installed on the rear axle and the two non-radials on the front axle.

The impact of a lower speed rating:

Although we don’t recommend it, if you use a tire with a speed rating lower than your vehicle’s original tires, you will reduce your vehicle’s top speed limit to the tires’ speed rating. The handling of a performance vehicle may be different when the replacement tires are not the same speed rating. Refer to the vehicle owner’s manual to identify any tire speed rating restriction that could affect operation of the vehicle.

Can you mix different speed ratings on your vehicle?

For best performance, use the same size and type of tire on all four wheel positions. But if you do mount tires with different speed ratings on your vehicle, make sure that:

• The lower speed-rated tires should always be placed on the front axle. This is to prevent potential over-steering (your vehicle doesn’t follow your steering, turns more sharply and may spin).

How to read speed ratings:

• Tire speed ratings range from A (the lowest) to Y (the highest). However, the chart is not completely in alphabetical order. For example, H for high speed is between U and V.

All the tire size information is located on your tires’ sidewall.

DOT signifies that the tire complies with the United States Department of Transportation and Transport Canada tire safety standards and is approved for highway use.

Example:
DOT M5H3 459X 065

The first two digits following DOT designate the tire's manufacturer and plant code. The third and fourth characters denote the tire size. The fifth, sixth, seventh and eighth (optional) characters identify the brand and other significant characteristics of the tire. The ninth and tenth characters denote the week the tire was produced. The final number(s) signifies the year in which the tire was manufactured.

For Michelin brand tires, DOT markings related to the week and year of production will have an additional symbol for the decade of the 1990s. It will be shown as a triangle following these last three numbers.

Beginning in year 2000, an additional digit was added to the serial number to allow the year of production to have two digits.