It is hard to choose a poorly on a motor these days if you stick with the latest mid drives from the big three - Bosch, Brose and Shimano. There are other motors, like Yamaha or Panasonic, but neither of them places on our podium at the moment. Keep in mind that the most raw power may not, in fact, be the most important thing for your experience. The smoother riding, longer range motors got up the steep hill just fine, just a little slower - and they probably would have gone way further after the hill. With the same battery, the hare might win the hill, but the turtle will always finish the race.
In real world testing on the steepest of hills (with equal rider wattage input), here is the descending pecking order of the fastest climbing eBike motors, from most fastest to the most tame:
King of the hill
Bosch's most powerful motor is tuned for climbing trails fast, and it is the top climber in real world testing on or off road. It is limited to 20mph assistance so if you need a higher top speed the Performance Speed is the way to go. The Performance Line CX drive has what Bosch calls Uphill Flow - support starts at very low pedal frequencies – this makes it easier to set off when already on a hill or to drive out of tight curves.
Tied for 2nd Place
The S motor scores in the top three in terms of raw power - the latest from Brose elivers substantial improvements to motor performance over the T version of 2017, high torque is delivered over a wider cadence spectrum, it feels faster and it is. There are several versions of the S motor optimized for each use - street 20mph and street 28mph, and off road for steep climbs. Specialized uses the S motor, but calls it "Turbo 1.3".
Shimano is getting traction with mountain bikers with the E8000 motor system that is lighter than both Bosch or Brose yet has plenty of gusto to climb hills. Shimano has impeccable racing credentials, so they have really stepped up their game to distinguish themselves with the MTB focused group. A full 2.5 lbs lighter than Bosch's Performance CX, it also has the narrowest "Q factor" and allows for shorter chainstays. Just because it is lighter does not mean it is not powerful - it has 70 Nm of torque - in real world testing it is neck in neck with Brose S, and just shy of industry standard Bosch Performance CX.
The Performance line is Bosch's most powerful street motor is tuned for a dynamic sportier ride, vs the active line's daily rider & leisure emphasis, and is the motor system to have on a premium sporty eBike. Pushing 63 Nm and available in a 20mph and 28mph versions. We just don't see any problems with the Bosch setups, so peace of mind is included.
The Brose T motor is focused on a "natural" feeling power delivery and hitting the perfect balance between power and efficiency to ensure maximum range. Torque peaks at 90 nm, but in order to get the most from the T motor, your pedaling cadence needs to be over 70 rotations per minute. Specialized uses the T motor, but calls it "Turbo 1.2" and it is bluetooth capable.
Note that all of the speed motors (assistance to 28mph) are not the fastest steep hill climbers. This is because power must be spread over a wider speed range. Of course a speed eBike is going to be fastest if already going 28mph when approaching an easy hill. Probably on moderate hill as well, with head start and substantial rider pedaling force. But the only benchmark metric for max raw power are steep hills.
Usually overlooked for its sexier siblings in the Performance line, Bosch's Active line is the bulletproof mainstay of most high quality, modern city eBikes. Especially suited for upright city cruisers, It gives just the right amount of assistance for daily commuting and relaxed tours, with the best battery range in the Bosch line. Bosch Active line is changing for 2018 but will no doubt continue to have the best in class reliability for everyday and leisure riding.
Entry level Steps E6000 is lighter and more affordable than Brose or Bosch, and the performance is no slouch compared to the most common 20mph city oriented motor, the Bosch Active line. Like Bosch, they use a proprietary battery along with their motors. Batteries for City systems are externally mounted on the back rack or frame mounted on the downtube, and on the small side at 400 watt hours. Overall the system is less bulky and lighter - and price ranges of 2-3k they lead the industry for value in a mid drive.
Find out why motors perform differently