I PURCHASED A KIT THAT TOOK ABOUT 6 HOURS TO INSTALL. IT WAS A ENGINE THAT MOUNTED TO FRAME AND THEN HAD SPROKET SECURE TO SPOKES, WORKED FOR ABOUT 15 MINUTES. JUNK, I THEN BOUGHT A FRICTION DRIVE KIT. IT TOOK ME 20 MINUTES TO HOOK UP ENGINE THAT THEY TOLD ME WOULD BE COMPATIBLE AND I LOVE THIS UNIT. I CAN GO ABOUT 38 MPH AND I WEIGH ABOUT 280 THIS KIT ROCKS. BMP IT SOUNDS LIKE I WORK FOR THEM BUT I ASSURE YOU I DON'T I AM A NURSE AND LIVE IN MINNESOTA 