Electric Bike Action Bike Test: Bulls Copperhead EVO AM 4 Trail Bike

Bulls Copperhead EVO AM 4

Both traditional and electric. They offer a bigger variety of bikes in Europe than in the U.S., so the U.S. side is picky about what they bring in. On the traditional mountain bike side, in the past they’ve offered a hardtail called the Copperhead. This year they’re offering a full-suspension electric-assist mountain bike line called the Copperhead EVO AM series. 


Bulls started with a 6061 aluminum frame with the battery integrated into the downtube. It’s a pretty conventional front and rear triangle combo. The sloping top tube is not low enough to make it a step-thru by any means, but it curves slightly at the bottom to level off, giving you plenty of stand-over clearance. There’s still room in the front triangle for a bottle cage, though likely you’ll use their side-mounting bottle for it.


One cool and fairly unique feature on the Copperhead—perhaps we should say “features,” because there’s two of them. The bike comes with a Monkeylink receiver on the stem and at the seatpost clamp. These are magnetic, pre-wired receivers for lights, so you can run them only at night or leave them on full-time. Lights are sold separately. We got a set, and they’re compact and plenty bright.

Another feature of the rear Monkeylink mount is that you can use it for a Monkeylink fender that not only helps keep mud off your back, it also keeps it out of the Monkeylink receiver.

The Bosch Kiox display is really easy to read, regardless of how bright it is outdoors. It adjusts automatically.

The Shimano XTR 1×12 drivetrain proved perfect for everything we tried it on. We were never wanting for higher or lower gears. We did, however, often find we’d shift two to three gears at a time, because the steps were so small.

The bike comes with a Limotec dropper post. Depending on the frame size, most come with 100mm of travel, but the large frame comes with a longer 125mm of travel to get the saddle out of the way when you need it to.


The Copperhead comes with a fourth-generation Bosch Performance Line CX. The latest generation of the CX is significantly different than previous versions. It’s not a refinement from the previous generations. The Bosch engineers started over and…