I used a Z.A.P. friction drive for about nine years with a single 12 volt 21 AH battery in all sorts of weather, at least the sort we get here in N. Florida. As a pedal assist device it was perfect. The tire barely showed any extra wear after all that time. Unassisted the bike went 8 mph but I have no idea of how far because I always pedaled. With careful use I had no problem getting 15 miles out of a good battery and eventually came up with a system to carry a spare that was effective.
The real advantage of the Z.A.P. system at the time I got it was that you could merely turn the cam lever and it would be totally disconnected with no drag and only the weight of the motor and battery as a deterrent which was minimal. This is unlike the 5304 with 4 SLA's on the same bike.
Before I had confidence in the 5304, I left the Z.A.P. with battery in place on the bike and it pushed everything at the same 8 MPH which was a good thing as a fuse holder decided to self destruct the second time I had the new system out and used the Z.A.P. to get home. With a new fuse holder for the 5304 battery pack in place I sold the Z.A.P. on eBay and got a very good price for it.
Mike
