§ 74.59 WEIGHT ON TIRES.
   Weight of load; width of tire. No person, firm or corporation shall transport over the improved public streets, alleys, intercounty highways, state highways, bridges or culverts in this municipality, in any vehicle propelled by muscular, motor or other power, any burden, including weight of vehicle and load, greater than the following:
   (A)   (1)   In vehicles having metal tires three inches or less in width, a load of 500 pounds for each inch of the total width of the tire on all wheels;
      (2)   When the tires on such vehicles exceed three inches in width, an additional load of 800 pounds shall be permitted for each inch by which the total width of the tires on all wheels exceeds 12 inches.
   (B)   In vehicles having tires of rubber or other similar substance, for each inch of the total width of tires on all wheels, as follows:
      Tire Width         Load Limit
      (in inches)         (in pounds)
         3         450
         3½         450
         4         500
         5         600
         6 and over      650
   (C)   The total width of tires on all wheels shall be, in the case of solid tires of rubber or other similar substance, the actual width in inches of all such tires between the flanges at the base of the tires, but in no event shall that portion of tire coming in contact with the road surface be less than two-thirds the width so measured between the flanges.
   (D)   In the case of pneumatic tires, of rubber or other similar substance, the total width of tires on all wheels shall be the actual width of all such tires, measured at the widest portion thereof when inflated and not bearing a load.
   (E)   In no event shall the load, including the proportionate weight of vehicle that can be concentrated on any wheel, exceed 650 pounds to each inch in width of the tread as defined in this section for solid tires, for each inch in the actual diameter of pneumatic tires measured when inflated and not bearing a load.
(R.C. § 5577.03) ('73 Code, § 71.39)