Speed controllers to use with mobility scooter motors?

[SnowLabs]

Thanks, I'll have to do some more research for motors.
As for the gearing and wheels, I'm going to build something from scratch - the bot I'm building will require two large wheels for drive.

I'm currently looking for wheels with a diameter of 12" or so. A lot of the wheels I'm looking at have been wheels for industrial trolleys, and have ball bearings making them impractical for drive. Do people normally get something like go kart wheels with wheel hubs, or something else?

What the best way to mount the sprocket and wheel to the axle? Do people normally get something custom made, ie gears and axle that they get keyed? Sorry for all the questions, I'm just trying to work out the best way to mount the wheels/sprockets.