This is my attempt to make a simple single stage dual speed gearbox for a WCD.
Low gear: 5.45:1 (60/11)
High gear: 3:1 (54/18)
Since the gearing is pretty aggressive this design would be best paired with small wheels. A 3.5” Colson is about as small as could be used without the 60 tooth gear being too close to the ground. A 3.5” wheel corresponds to 12.09FPS and 21.98FPS adjusted (81%) top speeds.
The design uses an automation direct single acting spring loaded pneumatic cylinder. This has the benefit of defaulting into low gear if the system isn’t pressurized. This could be beneficial for autonomous if we forget to pressurize the tanks before the start of a match.
Two 9mm width belts would be used with the VexPro toothed pulley to transfer motion to the front and rear wheels. Having the belts on the outside of the frame rail gives us less space between the frame rails, but has the benefit of making the belts easily accessible if they need to be changed.
Some concerns I have with the design are the wheel being cantilevered father than normal from the frame rail, the 60 tooth gear being so close to the ground, and the gearing being so aggressive. However, I still think the design could work well for a game with a relevantly flat ground where high top speeds are important.