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 .