I was working on my red S-750X bike over the weekend when I realized that it's much easier to mount and dismount the wheels and battery when the bike is upside down and sitting on the handlebars and seat! I had mounted the front battery into the front fork and it wasn't fully seated all the way into the dropout and so wasn't centered quite right. After I flipped the bike over (not an easy task considering the weight of the bike), I was able to easily mount and center both the front battery wheel and the rear motor into their dropouts. It's very easy to tell when they are in. They drop in with a solid clunk and don't wobble at all! I simply tightened the quick releases and voila. Done.