I'm a big fan of supporting the can. In both beetleweights (with those ebay 1000rpm gearmotors) and feathers, using RS550's on BaneBots P60's, I've had motors damaged from shock loads when hanging unsupported off the end of a gearbox.

Everything needs to be combat tough in no uncertain terms.
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<Patrician|Away> what does your robot do, sam
<bovril> it collects data about the surrounding environment, then discards it and drives into walls

ok guys thanks for the tips i have some thinking and planning to do