A High-Tech Control with Bluetooth Display Comes to Mountain Ebikes

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It wasn’t a totally new bike, it was the replacement for a 5-year-old Bulls mountain ebike which I had to abandon because Bulls could not supply me with a functioning battery for the Brose motor. For only $3,000, they upgraded me to their latest Copperhead model with Bosch motor and controls.

Up to now, ebike controls and displays have been rudimentary, as shown in the figure below. Speed is given in large letters in the middle of a small display, with your choice of 1) trip mileage (shown), 2) range, 3) average speed, 4) odometer, etc. at the bottom right. I usually zero the trip mileage at the beginning of the trip and monitor it in route. At the end, I make a mental note of the total mileage of my trip. It also displays the assist level you have chosen, between 1) Off, 2) Eco, 3) Tour, and 4) Boost (shown). The battery level is displayed as green and grey lights on the left side of the display. The A in the upper left indicates that the headlight and taillight are on.

The Bosch display on my new Bulls bike is even more rudimentary, as you see in the image below. Five blue lights (3 illuminated in the figure) on the middle of the display give the state of charge, and a colored chevron on the top indicates the assist level. Orange for TURBO, the highest level of assist, is shown in the figure.

The orange chevron indicates the amount of assist (in this case L4/Turbo), as labeled in the iPhone displays in later figures. The left toggle (shown in the figure above) with the two carrot symbols allow the selection of 1) map, 2) altitude history graph, as well as 3) speed, as shown below on my iPhone in later images. You can also choose 4) quantitative altitude display (not shown). You can also change between these displays by swiping the iPhone screen left or right. However, the toggle works even while wearing bicycle gloves. The right toggle with a – and * allows the selection of assist level: L1 (Eco), L2 (Tour), L3 (eMTB), and L4 full assist (TURBO) (shown in this case). Again, the toggle works even when wearing bicycle gloves.

See a closeup below of the control unit and my iPhone that are linked by Bluetooth. See the rubber bands that hold any size cell phone to the crossbar in the picture below with the clever holding device alone in the 3rd photo below.

Note: The Bulls Copperhead mountain ebike has a large 750 Wh capacity battery. This allows the following ranges at different settings. At L1 (Eco) 131 miles, L2 (Tour) 103 miles, L3 (eMTB) 66 miles, and L4 full assist (TURBO) 50 miles. To me, this means that Eagle River, a full 30 miles round trip for me on the beautiful Three Eagle Trail, is now accessible to me at full assist. At age 86, full assist makes me feel like I’m 20. I don’t like to ride at lower assist levels.

High-end mountain bikes like this one now have a drop seat, controlled in this case by a lever next to the left handbrake. “High level mountain bikes have drop seats—known as dropper posts—so riders can instantly change their saddle height using a handlebar lever without stopping. This allows a high seat for efficient pedaling uphill and a low seat out of the way for balance, clearance, and control on descents.” I personally only use the drop seat control to lower the seat when loaning my bike to a shorter rider. It allows me to change the seat height instantaneously and return it to the original high position when I am riding it myself just as quickly.

See the clever rubber bands below that hold any size cell phone to the bike crossbar in the photo below. You can see my iPhone held by those flat rubber bands in previous figures.

The Bluetooth connection to the app running on your phone is controlled as described above by a big toggle on the control.  You have four choices between 1) map as shown in the next figure below, …

… 2) a graph of your altitude history on your current trip as shown in the next figure below, …

… 3) your speed (14.8 mph in this case) in big letters on the iPhone display as shown in the next figure and 4) quantitative altitude (not shown).

As you can see on your generously large cellphone screen above, you also have the battery charge in the upper left (91% and 87% in these examples); the assist level in the upper right (TURBO in red in this case); your riding time lower left (37:52 min:seconds in this case); your trip distance lower right (8.6 mi in this case); range is given on the lower left (34 mi in this case); your average speed (13.6 mph in this case) on the lower right.

The figure below shows the Bulls/Bosch app homepage on my cellphone.

In the figure below, you can see one of the routes I have taken recently.

In the figure below, you see five of the routes I have taken recently. Note: the 4th is the route to Eagle River and back a total of 36 miles, ridden totally at full assist level.

Monkeylink headlight and taillight sockets:

The bike also has provision for a headlight and taillight using the Monkeylink system, which draws on the big ebike battery for power. You can see the headlight socket in the photo below. I seldom ride in the dark, so I don’t have much need for a headlight. However, a taillight is very important to me because I do some riding on highways and need motor vehicles to see me. However, since Monkeylink lights are expensive, I use an inexpensive battery-powered (USB-C charged) taillight. You can see the taillight illuminated in the last photo of this article.

Monkeylinks headlight socket. August 9, 2026. Fritz Hasler photo.

Below, you see me at our Three Lakes cabin with my Bulls mountain ebike. See the bright battery taillight illuminated, which I use in blinking mode. Also, see the rearview mirror on the handlebars. In addition, see the slow-moving-vehicle red triangle on the back of my pack. These are the things I do to keep safe with traffic on highways. The off-road trails and backroads are safe in my area, but I also need to ride on roads with significant traffic. You also see the bow saw in my pack that I use to cut the many trees that have fallen and blocked my off-road trails over the winter and during a recent windstorm.