Our drivetrain is a custom version of AM’s 446 drive module using a mixture of AndyMark and VexPro parts. As stated earlier, 2 CIMs per side and 8 4” Versa Wheels. The center wheels are direct driven using a standard AM shifter through a 48/50/60 gear set, slightly slower than a standard 446, end wheels are chain driven. What probably set us apart is the longer octagon shaped drive base with 4” side rails and a full length belly pan. I nicknamed it “The Tank” due to its rigidity, which allowed for end wheels to have minimal rocker, increasing pushing power/stability without adversely affecting turning.