On the VexPro website, it states that there is a total of 84 tooth spacing. For my team, we had a 11 tooth pinion gear on the motor, and this corresponded with a a 72 tooth gear, which we also ordered from the VexPro website. These details and four different gear ratios should be on the VexPro website on the description for the clamping gearbox, and the gears should be on another page. Here is the link to the gears:
http://www.vexrobotics.com/vexpro/mo...-hex-bore.html