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


it’s tuned to start off immediately and give you a push. Response time feels immediate, because the torque, cadence and speed sensors are reading 1000 times per second, and that includes a virtually unnoticeable drop in power when shifting.

Since Bulls has become as commonplace in the e-bike market as they have with pedal bikes, much of the technology has transferred over.

We do prefer e-MTB mode on most rides, but a few of the really steep climbs had us reaching for Turbo, just to keep our momentum going. The bike, with this motor, absolutely loves devouring climbs. On the previous Bosch motors, when you passed 20 mph, you could physically feel the drag of the motor while pedaling. No more. Now, when you’re pedaling through some flat ground, you don’t have to pedal harder.

For our first ride, we set the sag on the RockShox suspension at 25 percent. That offered a good starting point, but almost felt a little stiff. Setting sag at 30 percent provided even better performance, and even over some rough, rocky terrain with a few decent drops, we never bottomed it out. The combination of the Lyrik Ultimate fork and Super Deluxe RT rear shock with two tokens was spot-on. It was supple and provided excellent smallbump compliance.

Overall ride quality on the trail is outstanding. There was nothing we threw at the Bulls that it didn’t take in stride, letting us ride faster and a little harder than our own comfort zone.

The bike always felt planted with sure-footedness in corners, and it really rides great on every surface. You can run it with lower pressure for softer stuff, and the 27.5×2.8-inch, plus-size tires offer plenty of volume to run a bit lower pressure without much danger of pinch-flatting.


There are lower-spec, lower-priced versions of the Copperhead EVO line. The AM 1 starts at $4899. For higher spec and a bit more money, you can get the AM 2 or step up to the AM 3. The AM 4 is the flagship of the series, with the best components of the bunch.

Even with the lighter motor, it’s a bit heavy in the higher-end e-MTB market. That can be a ding against it, but it does make it feel more planted and stable when you’re flying down the trail. The geometry is good and suspension is excellent If you’re an all-mountain rider who wants a powerful motor and great connected features, the Copperhead EVO AM 4 is worth a serious look.

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