I agree that the best range would be attained at the most efficient motor rpm but how do we determine which rpm is the most efficient? Then there is the efficiency of the transmission itself as a variable. I am no engineer but I made a fair attempt to research gear drive efficiency and there are many variables there as to the number of gear engagements, the relative diameters of the gears and the load on the drive. Lightly loaded drives are less efficient than more heavily loaded ones and a small gear driving a large one is less efficient than two gears of the same size so every time you shift to a different ratio and a different load you are changing the efficiency of the transmission. I would imagine the motor efficiency at a given rpm also changes based on the load placed on it. So many variables ! So being a practical person I did some simple tests. These were done on 3 consecutive days at an ambient temp of 60 F. I charged the bike overnight and then before starting the ride I topped up till the amps went to zero. I tried to keep the same speeds and to accelerate from stops just staying with traffic. The loop I chose is 60 miles with everything from 35 mph suburban roads with stoplights to 60 mph highway and half on the flat and half on hilly rural roads. I checked the % left at the halfway mark and the finish. I recorded the results but don't have that here at home. All runs were done in sport mode for max regen. The first run was in 5th gear, then 4th gear and lastly in 3rd gear. No shifting, just left it in the same gear all the way. Fourth and fifth gears used exactly the same % of battery! That surprised me. Third gear was the least efficient. I didn't try second because you can't do 60 mph .Starting out in fifth the throttle response is pretty dead. Horrible I would say so that is out and it did nothing to improve range. Fourth was the winner, the bike is perfectly drivable in traffic and as the speed increases the power is decent. There is probably a way to drive always keeping the motor at it's optimal rpm for the given load but even if you could figure it out it would probably be impractical. So when I am just in touring mode and want max range I drive in fourth sport. When I am not going for max range I just go as fast and accelerate as hard as I want in the gear that is appropriate. Sometimes I take 200 plus mile rides and I want the maximum range to cut down on charging times. I carry an extra 2000 watt portable charger to help speed things up at the level 2 EVSEs. I test rode an Energica Eva today. I was impressed. They have come out with an 18.6 K nominal battery and DC fast charging is standard but only a 3.3 K onboard charger. That is a bike you could actually tour on.
