Tire Safety and Maintenance

• You should always check each tire's air pressure (including your spare) at least once a month and always before a long trip.  Always check when they're cold, at least three hours after the vehicle has been stopped.

• Load Carrying Limits molded into the tire's sidewall should never be exceeded.  Consult a trained tire professional to verify limits for the tire that you've chosen.

• If for some reason you run over glass, rocks, curbs, or other foreign material, check the tire for external damage. If you suspect damage but can't see it, have the tire dismounted and checked for internal damage.

• Having your tires rotated regularly achieves more uniform wear on each tire.  If no time period is specified in your owners manual, then the tires should be rotated every 7,500 miles.

• If you get stuck in mud or snow don't spin your tires. Spinning, even for a few seconds can build up heat and damage your tires.

• Properly balanced tires and wheels turn with all their weight distributed equally.  Unbalanced tires can result in a vehicle shimmying (side to side motion) and tramping (hopping up and down).

• Check your tires at least once a month for uneven wear and foreign objects wedged in the tread.  

Proper Inflation

• The tire pressure should never be below the recommended pressure listed on the vehicle placard nor above the above the maximum branded on the sidewall of a specific tire in normal driving conditions.

What to Look For in Choosing a Tire

• Buy the right tire size. The appropriate tire size for your car can be found in the owner's manual or on a placard located somewhere on your vehicle.  Also, consider the original equipment when purchasing a replacement tire.  Please check  and double-check the size of the tire(s) you need before ordering ( measure twice ... order once! ).

• If the original tires were speed rated, it is recommended to replace them with tires of the same or higher speed ratings.

• When tire shopping, keep in mind that the lowest price may not necessarily be the best value. As a consumer, finding the highest quality tire that will fulfill your specific needs at the most competitive price should be the ultimate goal.

• Dimensions shown in tire charts are based on non-scientific measurements of inflated tires. Dimensions can vary based on rim size and inflation.

How To Read A Tire's Sidewall

Passenger Example:   P215/65R15 89H

• The "P" stands for "P-Metric" or "Passenger".  This generally means this is a North American tire, as European tires typically don't have the prefix "P".

• The first number (215 in this example) is a three-digit number which refers to the section width of the tire at it's widest point, in millimeters.

• The second number (65 in this example) refers to the aspect ratio, which is the relationship between the tire's height and it's width.  In this example, the sidewall's height is about 65% of the tire's width.

• The letter following the aspect ratio is usually an "R" standing for radial construction.  Other types are "B" for belted construction and "D" for diagonal construction.

• The next number indicates the diameter of the wheel rim on which the tire will fit (15 inches, in this example).

• The "89" in this example is the load index. The load index indicates the maximum weight that each tire is able to bear.  See the chart below for further information.

• The "H" is the speed rating.  The speed rating of any tire is an indication of the top safe speed for each tire.  A higher rated tire will generally give better traction and improved steering at lower speeds.

Light Truck Example:   LT235/85R16M+S

• In this example the prefix is "LT" which denotes Light Truck.

• The "M+S" suffix indicates this tire is used in mud and snow applications.

Speed Ratings

• Q = 99 MPH, 160 km/h

• S = 112 MPH, 180 km/h

• T = 118 MPH, 190 km/h

• U = 124 MPH, 200 km/h

• H = 130 MPH, 210 km/h

• V = 149 MPH, 240 km/h

• Z = 149 MPH, 240 km/h and over

• W = 168 MPH, 270 km/h

• Y = 186 MPH, 300 km/h

Load Ratings

• The load rating (load index) indicates the maximum weight that each tire is able to bear.  See the chart below that shows the relationship between load index and the actual weight.

Load Range

• There is no common industry-wide definition of ply rating.  Truck tires are frequently marked with ply ratings and equivalent Load Range.  The table shows the conversion between ply rating and load range.

Tire Feature Codes

• ORBL- Outlined Raised Black Letters

• ORWL - Outlined Raised White Letters

• RWL - Raised White Letters

• RRBL - Recessed Raised Black Letters

• BSW - Black Sidewall

• WW - White Wall

• BW - Black Wall

• XL - Extra Load (Michelin)

• SL - Standard Load (Michelin)

• BCS - Black Circumferential Serration

• BL - Black Letters

• BSL - Black Serrated Letters

• BSB - Black Serrated Band

• ENWL - Extra Narrow White Letters

• ROBL - Raised Outlined Black Letters

• OWL - Outlined White Letters

• OBL - Outlined Black Letters

• OGL - Outlined Gold Letters

• OWL - Outline White Letters

• RBL - Raised Black Letters

• SBL - Serrated Black Letters

• SRBL - Serrated Raised Black Letters

• SOWL - Slanted Outlined White Letters

• ROWL - Raised Outlined White Letters

• SVSB - Slanted Vertical Serrated Band

• VSB - Vertical Serrated Band

• WL - White Letters

• WS - White Stripe

Uniform Tire Quality Grading

• The UTQG is a quality rating system developed by the American Department of Transportation.  It is designed to allow easy comparison of vehicle tires.  On this website, UTQG gradings can be found in the manufacturer's specification PDF file.

Example of a UTQG Rating:      150 A B 

• The "150" indicates the treadwear rating.  A tire graded "150" would generally be expected to wear 1 1/2 times as well as a tire graded "100".

• The "A" is the traction rating. Tires are rated AA, A, B, and C with AA being the highest. This rating is an indicator of a tire's ability to stop.

• The "B" is the temperature rating.  Temperature ratings are graded A, B, and C, with A being the highest.  This is an indicator of the tire's ability to withstand prolonged high temperatures.

Vintage Tire - Radial Cross Reference Chart