Me: I had a total of seven knee surgeries over 14 months, and man, my fitness took a beating. Getting back on a bike was both liberating and frustrating. I just can’t go as fast, or as far, as I used to. But, you don’t have to fall victim to a flesh-eating bacterial infection during routine a ACL reconstruction to find the idea of an electric mountain bike appealing. 
First of all, you’ll get a RockShox Lyrik RC Boost solo fork with 150mm of travel. You don’t find this fork on many electric mountain bikes at this price point. The new Brose Drive S motor is also featured on this bike. This is great for e-MTBs because it has 5 nm more torque than last year’s Brose bikes. You’ll also get a top-of-the-line derailleur with a Shimano Deore XT 11-speed drivetrain.
Bosch’s flagship mountain bike system uses a mini drive ring with internal gearing to send its power to the drivetrain. There’s some resistance in the system over 25km/h, but when you first press down on the pedals there’s an impressive surge of power, and it offers good support over a wide cadence range. Its size has an impact on the width of the cranks (the Q-factor) as well as the chainstay length of the frame, and it’s not the lightest system on the market at 4kg for the motor. On the other hand, Bosch is the most established player on the market, and its system has proven itself over many years.

The distance range of an electric mountain bike refers to the distance you can travel on a single battery charge given a specific set of circumstances. All of the e-bikes we tested have roughly the same battery storage capacity, but outside variables like rider weight, pedaling input, terrain, trail conditions, and weather conditions may all affect the length of time or distance that a battery charge will last. To compare the distance range of the four models in our test we took the bikes out in their highest support setting and did out and back laps on the same trail until the batteries ran down from fully charged to completely dead. When we finished we recorded the distance and vertical gain that each model was able to complete and easily and objectively determined our winner.
Because the power is applied through the chain and sprocket, power is typically limited to around 250–500 watts to protect against fast wear on the drivetrain. An electric mid-drive combined with an internal gear hub at the back hub may require care due to the lack of a clutch mechanism to soften the shock to the gears at the moment of re-engagement. A continuously variable transmission or a fully automatic internal gear hub may reduce the shocks due to the viscosity of oils used for liquid coupling instead of the mechanical couplings of the conventional internal gear hubs.
While GM and Tesla are getting their toes wet, or at least implying that they might, and Ducati is at the table with a serious range of electric bikes, Yamaha is the Japanese entrant to the market. But this isn’t new news. The company has sold over 2 million electric bicycles globally, as well as 4 million drive units. It is a big player in this space and has been since it started. As with Ducati, you can’t buy an electric motorcycle from the motorcycle-heavy brand, but you can power up hills on road and off with one of their motorized products.
Due to high total weights of over 20 kg, it doesn’t matter whether the scale stops at 21.44 kg or 22.2 kg for a modern eMTB. In our test, the difference between the lightest and the heaviest bike was just under 4 kg. This is not to be ignored… but a little extra weight in the form of functional, reliable componentry is better than an ebike designed and constructed to be as light as possible, at all costs, but which ends up in the workshop more often than on the trail.
Visually, the Pedego City Commuter Classic Electric Bike is stunning – a smart blend of yesteryear's style and today's technology. Pleasantly high handlebars, a sprung seat, and lovely Schwalbe Fat Frank tires make it very comfortable. Stopping is taken care of by powerful disk brakes, front and rear. Lights are included, as is a useful cargo rack. From an e-bike standpoint, the Pedego Classic City Commuter sports a reliable, hub-mounted motor driven by a 36-volt, 10-amp battery. There's a digital display with a trip computer, odometer, speedometer, pedal assist level, and battery charge information.
Over the course of our testing, our testers universally agreed that the HaiBike XDURO AllMtn 8.0 had the most responsive and robust motor. The system felt almost twitchy, raring to go with a torquey feel that started the moment you pushed on the pedals. It got up to speed quickly and felt like it had the fastest top speed of all the models we tested. The power output was smooth and consistent, and shifting between the system's 5 support settings went off without a hitch. Testers also loved that the power band extended for a moment after you stop pedaling, not quite as long as the Commencal, but enough to still be a benefit on the climbs. The Commencal has a similarly strong motor, but couldn't quite match the torquey feel of the HaiBike or the top speed, although it has an even longer push of the power band when the pedaling stops. Both the Trek and the Specialized motor systems felt slightly less powerful, still offering plenty of pedal-assist support mind you, but that also resulted in the most efficient motors and longer distance ranges than the models with more brute power. Note that our Turbo Levo showed up with a top speed limit of 16mph and not the 20mph. We were very disappointed with 16mph as a max speed. Luckily, we were able to get it adjusted back to 20 and were then quite happy. If you buy a Specialized, make sure it's set to 20mph.
On the AM 4 you get 150mm of travel via a Fox Factory 36 Float fork, 11-speeds from a Shimano Deore XT drivetrain, and Magura MT-Trail hydraulic disc brakes. They also don’t gip you on the dropper with a wonderful, wonderful KS Lev. In terms of geometry, the build is pretty dope. It’s a nice slack feel, so you can do some solid downhills. A DT Swiss wheelset along with Magic Mary tires give you a lightweight and smooth ride.
Government agencies like the USDA National Forests and the Bureau of Land Management should distinguish between electric pedal-assist eBikes (Type 1) and self-propelled eBikes (Type 2). The former are still human-powered whereas the latter are fully motorized like a motorcycle. Some states like California are already recognizing the different classifications of eBikes and allowing some on trails while prohibiting others. This clear distinction should help us avoid expanding our mountain bike trails to motorcycles, or worse yet, have trails that are currently open to mountain bikes relegated to “hiking only.”

In a parallel hybrid motorized bicycle, such as the aforementioned 1897 invention by Hosea W. Libbey, human and motor inputs are mechanically coupled either in the bottom bracket, the rear wheel, or the front wheel, whereas in a (mechanical) series hybrid cycle, the human and motor inputs are coupled through differential gearing. In an (electronic) series hybrid cycle, human power is converted into electricity and is fed directly into the motor and mostly additional electricity is supplied from a battery.
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