A combination registered in this Commonwealth or any other state at a weight between 79,001 and 80,000 pounds which has six axles, an external bridge measuring 43 feet or more, and an internal bridge measuring 32 feet or more shall be in compliance with the formula in 75 Pa.C.S. § 4943(b)(1) if the tandem axles of the towing vehicle do not exceed 34,000 pounds and the three axles of the trailer do not exceed 42,500 pounds.
67 Pa. Code § 185.4
This section cited in 67 Pa. Code § 185.3 (relating to groups of consecutive axles).