The hobby shop staff recommend wheel collars for lots of things. I wouldn't doubt by the time I add the three wheel collars I see a place for, this small motor might steady at a slower speed and direct-drive might be a better solution.

I was thinking, I wonder how much of a chance I stand of burning up the board if I wire more batteries into motor stage. I've heard of Battery Eliminator Circuits along these lines, but anything I can do cheaper...well, my rig only has to outlast my interest in this particular configuration