[Rick TYler]

Originally Posted by JesseK

Usually it's just as much weight to do the bearing blocks for a direct drive setup as it is to do an AM hub with AM flat sprockets with extra chains. Since it's more difficult to do the former, most teams stick with the default method.

My old FRC team has never built a really great robot (sad, but true), but their chain-driven, 6WD chassis with the KOP gearbox has been bulletproof all four of the last seasons. The concerns about breaking #35 chain (in my experience) are exaggerated -- if you don't do anything weird or stupid, they simply won't break before the motors stall out. When you start getting into more exotic choices, stuff starts breaking. It might be worth it if you have a sophisticated robot and build process, but I think most teams would be well-advised to go with a proven drive-train and spend their brain cells on building better game mechanisms.