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Photo by David Niddrie
NuVinci HarmonyDetail of the NuVinci Harmony Intelligent Drivetrain shifting system.
Manufacturers are adding electric shifting to their internal-gear hubs. While a novel concept to most riders, this technology holds benefits that bike and e-bike companies should be paying attention to.
Shimano, who already offer electric shifting on high-end road bike components, have added battery power to their 8- and 11-speed Alfine internal-gear hubs. Shifting is made possible by a small motor mounted to the side of the Alfine Di2 hub. No longer requiring cable tension shifting, the switch to electric is meant to further reduce maintenance on an already near maintenance-free system.
The NuVinci Harmony from Fallbrook Technologies is promoted as an intelligent drivetrain. The system, based around the popular N360 continuously variable internal gear hub, provides manual and automatic shifting. In the automatic mode, a rider selects his or her preferred pedaling cadence and the hub auto-shifts as speed and terrain changes. The system is seen as a complement to e-bikes with mid-drive motors.
SRAM’s E-matic hub combines electric-assist with an automatic transmission. No cables, shifters or controls are needed. Torque sensors monitor a rider’s effort and provide proportional electric-assistance as needed. At higher speeds, the automatic transmission shifts to a lower, more effi cient gear while still providing electric-assist from the motor. The Electra Townie Go, a no-fuss cruiser bike, will be available with SRAM’s E-matic hub for under $2,000.