pic: Triwheels

[Cothron Theiss]

Originally Posted by pilleya

Why go for idler gears, surely it would be simpler to just have 1 large gear turning 3 large gears attached to the wheels and do the 2:1 reduction else where, such as with the belts/ chain driving the modules or in the gearbox ( custom 3rd stage to get adequate reduction etc)

I'm not on the OP's team so I don't know, but I assume it is because if the driving gear was large enough to contact the three driven gears, they wouldn't get the 2:1 reduction they need. The driving gear has to be small enough for the desired reduction.