Shimano Pedal-Assist Bicycle Mid-Motor Description And Specs

We take a look at Shimano eBike mid-motors to see how they work.

Shimano Steps E6100
Shimano Steps E6100 for city/on-road operationShimano

Shimano has been highly respected for decades for its design and production of the full range of bicycle components and complete bicycles. It has entered the field of electric pedal-assist with two mid-motor units, the Shimano Steps E6100 for city/on-road operation and E8000 to include unpaved road and mountain conditions. Moving away from fixed pedal-assist modes, Shimano now allows the user to custom-tailor assist levels via his or her smartphone, tablet, or computer.

Both Shimano motors base their control on the usual suite of three sensors—one to measure the torque applied by the rider to the pedals, another to measure cadence (pedal rpm), and a third to monitor bicycle speed. The variables are measured a zillion times per second, allowing electric assist to operate almost imperceptibly, multiplying the rider’s effort seamlessly throughout the pedal stroke.

The weight of the E6100 mid-motor is 6.35 pounds (2.9 kilograms). Like the others, its components are densely packaged into a narrow aluminum case which has its own crank axle projecting to either side. This case is integrated into the bicycle’s frame in the usual bottom-bracket location.

Power comes from a 36-volt lithium-ion rechargeable battery of either 418 or 504 watt-hour (WH) capacity, which can be mounted either on a rear carrier or on the frame downtube. The 418-WH battery weighs 5.9 pounds (2.7 kilograms). A charging port allows the battery to be charged in place, or it may be conveniently removed for charging.

The 418-WH unit charges to 80 percent in two hours, or from 0–100 percent in four hours. For the 504-WH battery, the 80 percent charge takes 2.5 hours and the 0–100 percent charge five hours.

Shimano tell us these batteries are capable of lasting through 1,000 charge/discharge cycles—more if they are not fully discharged at each cycle.

Range per charge obviously will vary according to the conditions of use, but based on the usual 220-pound maximum rider-plus-bike weight, standard 23 kph (14.3 mph) speed, with minimal wind and flat roads, we are told the following:

Range with the 504 Wh battery is up to 105 miles in Eco mode, up to 75 miles in Normal mode, and up to 53 miles in High mode. These numbers are comparable to those of the other mid-motor manufacturers. Don’t get hung up on little differences—you can plan your ride and energy use by looking at the data presented on the screen of your handlebar-mounted control unit.

Shimano Steps E6100
Mode Eco Normal High
Assist % 50% 100% 200%

For the off-road E8000, the support modes become programmable via smartphone, tablet, or E-Tube, which is Shimano’s website and app for programming firmware. The three basic modes now become Eco, Trail, and Boost.

On their website you will find this explanation: "Dynamic Mode: Factory default with Boost set on high, Travel set on low. Explorer Mode: Boost and Travel set on medium. Custom Mode: Choose your support level for both Boost and Trail to match your unique riding style and intended terrain."

The basic idea is that Shimano has advanced beyond fixed levels of assist to as-you-like-it tailoring of assist via digital connectivity.

As with all these mid-motors, power averaged over 30 minutes of operation is limited to 250 watts (1/3 of a hp). Pedal assist ceases above 20 mph to preserve legal “electric bicycle” status.

Q-factor (width across the outer faces of the crank arms) for the E8000 is 175mm—comparable with any conventional mountain bike.

Technology and features are changing rapidly, so the language used to describe modes and options evolves with them. See Shimano’s website for the latest. All manufacturers in this fast expanding field are monitoring each other closely, assuring that product capabilities are closely comparable.