My thought is probally flawed - I am really tired right now but...
Wouldn't this be a two-faced question?
If you where going from the motor to the tranny than REDUCING the gear ratio - that would be easier on the tranny.
If you went from the motor to the tranny than INCREASING the gear ratio - wouldn't that be putting more strain on it?
It will take power to move the robot - I realize that - but if you can avoid more stress than what is needed on the tranny - wouldn't that be better?
Agian - I am really tired and I am probally going to go to bed after this - but thoes are my thoughs. Hope this helps! (and I hope I'm right!

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