Intended Use Of Tire

Passenger Vehicle. When a tire size begins with a P, it signifies the tire is a p-metric size that was designed to be fitted on vehicles that are primarily used as passenger vehicles. This includes cars, minivans, sport utility vehicles and light duty pickup trucks (typically 1/4- and 1/2-ton load capacity). The use of p-metric sizes began in the late 1970s and they are the most frequently used type of tire size today.

Tire Width

Following the letter(s) that identify the type of vehicle and/or type of service for which the tire was designed, the three-digit numeric portion identifies the tire's section width/cross section in millimeters.

The 245 indicates that this tire is 245 millimeters across from the widest point when mounted and measured on a specified width wheel. Because many people think of measurements in inches, the 245mm can be converted to inches by dividing the width in millimeters by 25.4 (the number of millimeters per inch).

245mm / 25.4 = 9.65"

Aspect Ratio

The ratio of the height of the tire's cross-section to it's width. 70 means that the height is equal to 70% of the tire's width.

Typically, following the three digits identifying the tire's width in millimeters is a two-digit number that identifies the tire's profile or aspect ratio.

The 70 indicates that this tire size's sidewall height (from rim to tread) is 50% of its width. The measurement is the tire's section height, and also referred to as the tire's series, profile or aspect ratio. The higher the number, the taller the sidewall. The lower the number, the lower the sidewall. We know that this tire size's section width is 245mm and that its section height is 50% of 245mm. By converting the 245mm to inches (245 / 25.4 = 9.65") and multiplying it by 50% (.50) we confirm that this tire size results in a tire section height of 4.83".

Construction Method

Radial. The R in the P245/70R17 108T size identifies that the tire has a radial construction in which the tire's plies "radiate" out from the center of the wheel. Radial tires are by far the most popular type of tire today representing over 98% of all tires sold.

If the R in the size was replaced with a D (P245/70R17 108T), it would identify that the internal tire body plies crisscross on a diagonal and that the tire has a "bias ply" construction. Tires using this construction are for light truck and spare tire applications.

Rim Size

The 17 indicates the tire and wheel diameter designed to be matched together.

Tires that have a rim diameter expressed in inches (P245/70R17 108T, as well as 8, 10, 12, 13, 14,15, 17, 18, 19, 20, 22, 23, 24, 26 and 28) are called "inch rim" sizes. These are the most common types of tire sizes and are used on most cars, minivans, vans, sport utility vehicles and light duty light trucks.

Tires and wheels with unique rim diameters should never be combined with traditional "inch rim" tires and wheels.

Load Range/Ply Rating

This tire has a ply rating of which indicates how much load the tire is designed to carry at it's specified pressure.

Load Index/Service Description

2181lb load. The tire assigned numerical value used to compare relative load carrying capabilities.

The 108 represents the tire's service description. A service description identifies the tire's load index and speed rating. Service descriptions are required on all speed rated (except for Z-speed rated) tires manufactured since the early 1990s.

Speed Rating

190mph. The maximum speed that the tire can sustain for 10 minutes.

Today, the only tires that continue to include the speed rating "in" the tire size (P245/70R17 108T) are Z-speed rated tires. In this case, following the two digits used to identify the aspect ratio are the letters ZR to identify the tire's speed rating (Z) and its internal construction (R). Since 1991, all other speed ratings are identified in the tire's Service Description.

Intended Use Of Tire

Passenger Vehicle. When a tire size begins with a P, it signifies the tire is a p-metric size that was designed to be fitted on vehicles that are primarily used as passenger vehicles. This includes cars, minivans, sport utility vehicles and light duty pickup trucks (typically 1/4- and 1/2-ton load capacity). The use of p-metric sizes began in the late 1970s and they are the most frequently used type of tire size today.

Tire Width

Following the letter(s) that identify the type of vehicle and/or type of service for which the tire was designed, the three-digit numeric portion identifies the tire's section width/cross section in millimeters.

The 265 indicates that this tire is 265 millimeters across from the widest point when mounted and measured on a specified width wheel. Because many people think of measurements in inches, the 265mm can be converted to inches by dividing the width in millimeters by 25.4 (the number of millimeters per inch).

265mm / 25.4 = 10.43"

Aspect Ratio

The ratio of the height of the tire's cross-section to it's width. 60 means that the height is equal to 60% of the tire's width.

Typically, following the three digits identifying the tire's width in millimeters is a two-digit number that identifies the tire's profile or aspect ratio.

The 60 indicates that this tire size's sidewall height (from rim to tread) is 50% of its width. The measurement is the tire's section height, and also referred to as the tire's series, profile or aspect ratio. The higher the number, the taller the sidewall. The lower the number, the lower the sidewall. We know that this tire size's section width is 265mm and that its section height is 50% of 265mm. By converting the 265mm to inches (265 / 25.4 = 10.43") and multiplying it by 50% (.50) we confirm that this tire size results in a tire section height of 5.21".

Construction Method

Radial. The R in the P265/60R18 109T size identifies that the tire has a radial construction in which the tire's plies "radiate" out from the center of the wheel. Radial tires are by far the most popular type of tire today representing over 98% of all tires sold.

If the R in the size was replaced with a D (P265/60R18 109T), it would identify that the internal tire body plies crisscross on a diagonal and that the tire has a "bias ply" construction. Tires using this construction are for light truck and spare tire applications.

Rim Size

The 18 indicates the tire and wheel diameter designed to be matched together.

Tires that have a rim diameter expressed in inches (P265/60R18 109T, as well as 8, 10, 12, 13, 14,15, 17, 18, 19, 20, 22, 23, 24, 26 and 28) are called "inch rim" sizes. These are the most common types of tire sizes and are used on most cars, minivans, vans, sport utility vehicles and light duty light trucks.

Tires and wheels with unique rim diameters should never be combined with traditional "inch rim" tires and wheels.

Load Range/Ply Rating

This tire has a ply rating of which indicates how much load the tire is designed to carry at it's specified pressure.

Load Index/Service Description

2201lb load. The tire assigned numerical value used to compare relative load carrying capabilities.

The 109 represents the tire's service description. A service description identifies the tire's load index and speed rating. Service descriptions are required on all speed rated (except for Z-speed rated) tires manufactured since the early 1990s.

Speed Rating

190mph. The maximum speed that the tire can sustain for 10 minutes.

Today, the only tires that continue to include the speed rating "in" the tire size (P265/60R18 109T) are Z-speed rated tires. In this case, following the two digits used to identify the aspect ratio are the letters ZR to identify the tire's speed rating (Z) and its internal construction (R). Since 1991, all other speed ratings are identified in the tire's Service Description.

Intended Use Of Tire

Passenger Vehicle. When a tire size begins with a P, it signifies the tire is a p-metric size that was designed to be fitted on vehicles that are primarily used as passenger vehicles. This includes cars, minivans, sport utility vehicles and light duty pickup trucks (typically 1/4- and 1/2-ton load capacity). The use of p-metric sizes began in the late 1970s and they are the most frequently used type of tire size today.

Tire Width

Following the letter(s) that identify the type of vehicle and/or type of service for which the tire was designed, the three-digit numeric portion identifies the tire's section width/cross section in millimeters.

The 265 indicates that this tire is 265 millimeters across from the widest point when mounted and measured on a specified width wheel. Because many people think of measurements in inches, the 265mm can be converted to inches by dividing the width in millimeters by 25.4 (the number of millimeters per inch).

265mm / 25.4 = 10.43"

Aspect Ratio

The ratio of the height of the tire's cross-section to it's width. 50 means that the height is equal to 50% of the tire's width.

Typically, following the three digits identifying the tire's width in millimeters is a two-digit number that identifies the tire's profile or aspect ratio.

The 50 indicates that this tire size's sidewall height (from rim to tread) is 50% of its width. The measurement is the tire's section height, and also referred to as the tire's series, profile or aspect ratio. The higher the number, the taller the sidewall. The lower the number, the lower the sidewall. We know that this tire size's section width is 265mm and that its section height is 50% of 265mm. By converting the 265mm to inches (265 / 25.4 = 10.43") and multiplying it by 50% (.50) we confirm that this tire size results in a tire section height of 5.21".

Construction Method

Radial. The R in the 265/50R20 107T size identifies that the tire has a radial construction in which the tire's plies "radiate" out from the center of the wheel. Radial tires are by far the most popular type of tire today representing over 98% of all tires sold.

If the R in the size was replaced with a D (265/50R20 107T), it would identify that the internal tire body plies crisscross on a diagonal and that the tire has a "bias ply" construction. Tires using this construction are for light truck and spare tire applications.

Rim Size

The 20 indicates the tire and wheel diameter designed to be matched together.

Tires that have a rim diameter expressed in inches (265/50R20 107T, as well as 8, 10, 12, 13, 14,15, 17, 18, 19, 20, 22, 23, 24, 26 and 28) are called "inch rim" sizes. These are the most common types of tire sizes and are used on most cars, minivans, vans, sport utility vehicles and light duty light trucks.

Tires and wheels with unique rim diameters should never be combined with traditional "inch rim" tires and wheels.

Load Range/Ply Rating

This tire has a ply rating of which indicates how much load the tire is designed to carry at it's specified pressure.

Load Index/Service Description

2161lb load. The tire assigned numerical value used to compare relative load carrying capabilities.

The 107 represents the tire's service description. A service description identifies the tire's load index and speed rating. Service descriptions are required on all speed rated (except for Z-speed rated) tires manufactured since the early 1990s.

Speed Rating

190mph. The maximum speed that the tire can sustain for 10 minutes.

Today, the only tires that continue to include the speed rating "in" the tire size (265/50R20 107T) are Z-speed rated tires. In this case, following the two digits used to identify the aspect ratio are the letters ZR to identify the tire's speed rating (Z) and its internal construction (R). Since 1991, all other speed ratings are identified in the tire's Service Description.