A truck with 46-in.-diameter wheels is traveling at 60 mi/h.

60 m/hr * 1 hr / 60 min * 5280 ft/mi =  5280 ft/ min

 

46 /12  ft  * pi = 3.83333 pi  ft   circumference

 

5280 ft /min / (3.8333pi ft) = 438.44   rpm                 x 2pi = 2754.78 radians/min