I will bump this. Per the TM
Gear Ratio
M915A1 ........ 4.33:1
M915 ... 4.44:1
M916 through M920 ........ 6.17:1
Not verified but that is per the Tm
On a 915A1
11R22.5s = 41.3" tall Speed @ rpm 2000=57, 2150=61, 2450=70
12R22.5s/315/80/22.5s = 43" tall Speed @ rpm 2000=59, 2150=64, 2450=72
11R24.5s = 44" tall Speed @ rpm 2000=60, 2150=65, 2450=74
12R24.5s = 45" tall Speed @ rpm 2000=62, 2150=67, 2450=76
395/85/20 = 46.6" tall Speed @ rpm 2000=64, 2150=69 ,2450=78
14.00R20= 49.6" tall Speed @ rpm 2000=68, 2150=73, 2450=84