Tire Glossary




TermDefinition
LATERAL FORCE Force the causes a tire to move from side-to-side. During cornering, lateral force transfers weight from the inside of the tire, to the outside.
LIGHT TRUCK HIGH FLOTATION SYSTEM Light truck high flotation is identical to the Light Truck Numeric System, but with the addition of the diameter of the full tire added to the beginning. Example: 31x10.50R15LT – 31 = overall diameter of the tire, in inches; 10.50 = section width, in inches; R = radial; 15 = rim diameter, inches; LT = light truck. See LIGHT TRUCK METRIC SYSTEM, LIGHT TRUCK NUMERIC SYSTEM.
LIGHT TRUCK METRIC SYSTEM Similar to the P-Metric tire sizing except the letter “P” is replaced with “LT” for light truck. Example: LT215/85R16. LT = light truck; 215 = the tire’s section width, in millimeters; 85 = the tire’s aspect ratio; R = radial; 16 = rim diameter. See LIGHT TRUCK NUMERIC SYSTEM, LIGHT TRUCK HIGH FLOTATION SYSTEM.
LIGHT TRUCK NUMERIC SYSTEM This older sizing system is still used on older commercial vehicles. Example: 9.50R16.5SLT/D – 9.50 = the tire’s section width in inches; R = radial construction; 16.5 = the rim diameter in inches; LT = light truck; D = load range. See LIGHT TRUCK HIGH FLOTATION SYSTEM, LIGHT TRUCK METRIC SYSTEM.
LOAD INDEX A number that corresponds to the maximum load, in pounds, that a tire can support when properly inflated. Example: If a tire has a load index of 97, it can support 1,609 pounds (see chart below). Multiply … 1,609 x 4 = 6,436 pounds – the vehicle’s maximum load-carrying capacity. Because the maximum tire load capacity is branded on the tire's sidewall, the load index is used as a quick reference.
LOW VOID RATIO A tread pattern design that features a low degree of grooves and sipes, thus a higher amount of tread in contact with the road suface. Low void ratios are found on summer or three-season performance tires. See VOID, VOID RATIO, HIGH VOID RATIO.