mi = the technically permissible maximum mass on the axle designated ' i ' , where ' i ' varies from 1 to the total number of axles of the vehicle , uj = the technically permissible maximum mass on the solo axle or group of axles designated ' j ' , where ' j ' varies from 1 to the total number of solo axles and groups of axles , TM = the technically permissible maximum towable mass , and MC = the technically permissible maximum laden mass of the combination .