Kentucky Tire Regulations

Maximum Legal Weight Allowed

On Intersates and designated highways:

• 20,000 pounds per single axle, with axles less than 42 inches apart to be considered as a single axle.
• 34,000 pounds on 2 axles in tandem arrangement which are spaced 42 inches or more apart and less than 96 inches apart.
• 48,000 pounds on 3 axles which are spaced 42 inches or more apart and less than 120 inches apart.
• No single axle in any arrangement shall exceed 20,000 pounds or 700 pounds per inch of the aggregate width of all the tires on a single axle, whichever is less.
• The total gross weight of the vehicle and load shall not exceed 80,000 pounds.

All other state maintained highways:

• Class [A] Highways, 44,000 pounds
• Class [AA] Highways, 62,000 pounds
• Class [AAA] Highways, 80,000 pounds.

Maximum Permissible Axle Weight

Gross or axle overweight shall not be permitted on a combination unit of less than 5 axles; or on a single unit except off-road equipment such as a road grader, mobile crane, or other self-propelled unit. A vehicle shall not be issued an overweight permit that does not have a declared gross weight of at least 80,000 lbs. Maximum weights shall not be permitted unless all bridges and roads on the moving route have sufficient capacity to accommodate the load. The weight on a single axle in any combination shall not exceed the product of 700 pounds times the aggregate width in inches established by the manufacturer’s stamped tire measurement of all the tires on the axle, or the following axle or axle group weights, whichever is less.

• Steering axle – 20,000 pounds
• Single Dual Wheel axle – 24,000 pounds
• Tandem dual-wheel axle group if the combination vehicle has only five (5) axles total – 45,000 pounds
• Tandem dual-wheel axle group if the combination vehicle has six (6) or more axles total – 48,000 pounds
• Tridem dual-wheel axle group – 60,000 pounds
• Trunnion axle 48,000 pounds

Combination Truck/Semitrailer:

In accordance with 601 KAR 1:018 combinations units of five (5), six (6) and seven (7) axle configurations shall be limited to the following:

• Five (5) axle combination units may not exceed 96,000 pounds gross weight
• Six (6) axle combination units may not exceed 120,000 pounds gross weight
• Seven (7) axle combination units may not exceed 160,000 pounds gross weight

Source of information: https://drive.ky.gov/motor-carriers/Pages/OWOD-Legal-Dimensions.aspx