Steve, can you share some info about the gear motors?
First: as i read in most of the gear motor specifications, if the output shaft is blocked, it can damage the gears. Let's assume, that the shaft is never blocked cause it have enough power to drive the big wheel, but what happens if you turn (left or right) while the machine is not moving, are the wheels turning as expected, or are they still and sliding on the floor? (hope you can understand what i mean).
Secondly can the wheels turned by hand (slowly ofcourse), or could this also damage the gears?
(the 2 questions are the same, i know
)
I know this mostly depends on the gear ratio you're using, as i calculated, to get the max speed (1:1 -> 22 km/h, 1:14,5 -> 1,5 km/h), a max output of 50 rpm is needed. So i think, the best is a lower rmp motor as base to get the lowest gear ratio possible...