Weight per axle (weight on drivers divided by number of pairs of driving wheels) | Diameter of wheel center (inches) | Minimum thickness (inches) |
30,000 pounds and under | 44 and under | 1 1/4 |
Over 44 to 50 | 1 5/16 | |
Over 50 to 56 | 1 3/8 | |
Over 56 to 62 | 1 7/16 | |
Over 62 to 68 | 1 1/2 | |
Over 68 to 74 | 1 9/16 | |
Over 74 | 1 5/8 | |
Over 30,000 to 35,000 pounds | 44 and under | 1 5/16 |
Over 44 to 50 | 1 3/8 | |
Over 50 to 56 | 1 7/16 | |
Over 56 to 62 | 1 1/2 | |
Over 62 to 68 | 1 9/16 | |
Over 68 to 74 | 1 5/8 | |
Over 74 | 1 11/16 | |
Over 35,000 to 40,000 pounds | 44 and under | 1 3/8 |
Over 44 to 50 | 1 7/16 | |
Over 50 to 56 | 1 1/2 | |
Over 56 to 62 | 1 9/16 | |
Over 62 to 68 | 1 5/8 | |
Over 68 to 74 | 1 11/16 | |
Over 74 | 1 3/4 | |
Over 40,000 to 45,000 pounds | 44 and under | 1 7/16 |
Over 44 to 50 | 1 1/2 | |
Over 50 to 56 | 1 9/16 | |
Over 56 to 62 | 1 5/8 | |
Over 62 to 68 | 1 11/16 | |
Over 68 to 74 | 1 3/4 | |
Over 74 | 1 13/16 | |
Over 45,000 to 50,000 pounds | 44 and under | 1 1/2 |
Over 44 to 50 | 1 9/16 | |
Over 50 to 56 | 1 5/8 | |
Over 56 to 62 | 1 11/16 | |
Over 62 to 68 | 1 3/4 | |
Over 68 to 74 | 1 13/16 | |
Over 74 | 1 7/8 | |
Over 50,000 to 55,000 pounds | 44 and under | 1 9/16 |
Over 44 to 50 | 1 5/8 | |
Over 50 to 56 | 1 11/16 | |
Over 56 to 62 | 1 3/4 | |
Over 62 to 68 | 1 13/16 | |
Over 68 to 74 | 1 7/8 | |
Over 74 | 1 15/16 | |
Over 55,000 pounds | 44 and under | 1 5/8 |
Over 44 to 50 | 1 11/16 | |
Over 50 to 56 | 1 3/4 | |
Over 56 to 62 | 1 13/16 | |
Over 62 to 68 | 1 7/8 | |
Over 68 to 74 | 1 15/16 | |
Over 74 | 2 |
49 C.F.R. § 230.112