Currie Technologies 19 tooth freewheel sprocket assembly. This gear is most common one on Currie electric bikes which have an electro drive kit with a planetary gear system. All USPD Pro Drive kits with a version 1, 2 or 3 drive system use this gear. All Currie Electric bikes use this gear. 19 Tooth Freewheeling Sprocket For #25 Chain, includes star shaft. Roller clutch with one-way bearing. Rotates freely in one direction; fixed in other direction. Upgrading your scooter or bike sprocket.....Change your stock 15-tooth gear for a 19-tooth pinion to increase your top end by 3-5 MPH!This gear will work on a 12mm shaft for scooters as well. Does not require the use of the star shaft which is included with your purchase. sk-19t Home | New Arrivals | Hover Boards | Quadcopters | Electric Scooters | Electric Bikes| Razor Scooter Parts | Scooter Parts | PS4 | Xbox ONE | iWatches / Gadgets | Shipping | FAQ | About Us | Scooter Laws | Returns | Shopping Cart