BULLS Grinder EVO Review: Class 3 Gravel E-Bike

Written by: Chris Van Leuven | August 18, 2026 | Time to read: 6-7 min

Many gravel e-Bikes rely almost entirely on tire volume for comfort. The Grinder EVO adds a 63mm SR Suntour NCX-E air fork, which changes what you can reasonably ask of it. Sixty-three millimeters isn’t mountain-bike travel, and I wouldn’t pretend it is. But it’s enough to take some of the harshness out of washboard gravel, broken pavement, potholes, and rough dirt roads. That matters on a bike that may spend one hour on asphalt and the next on a county road that hasn’t seen fresh grading in years.

The Schwalbe G-One RaceGuard 700×40 tires reinforce that all-road personality. They’re wide enough to add grip and comfort on gravel without making the bike feel out of place on pavement. The drop bars are an important part of the equation, too. Multiple hand positions matter when rides get longer, especially if you’re coming from road or gravel riding rather than upright commuting. The Grinder EVO retains the familiar riding feel while adding the extra comfort and assistance of an e-Bike.

At roughly 52 pounds, it’s heavy compared with a traditional gravel bike. But that comparison only goes so far. You’re also carrying a Bosch speed motor, an integrated battery, suspension, hydraulic brakes, and commuter-ready hardware. I wouldn’t think of the Grinder EVO as a lightweight gravel bike with a motor added. It’s closer to an all-road bike built around longer, faster rides where the surface can change several times before you get home.

The Bosch motor is what sets the Grinder EVO apart from lighter electric gravel bikes. BULLS uses the Performance Line Speed Gen2 system, which provides Class 3 pedal assistance up to 28 mph. BULLS lists the System 2 motor at 73 Nm of torque, paired with a 500 Wh Bosch PowerTube battery and a Purion display. Charging time is listed at roughly 4.5 hours with the 4A charger.

That extra speed is useful in a different way here than it is on a pure commuter. On a mixed ride, you might spend 15 miles on pavement before reaching the gravel you actually came for. Class 3 assistance makes those connecting miles easier to cover without turning them into the main event.

The SRAM Apex 11-speed drivetrain fits that idea well. The 11–42T cassette gives you usable climbing range, while SRAM Apex HRD hydraulic disc brakes with 160mm rotors handle stopping duties. Nothing about that setup appears overly fancy. That’s a good thing. Apex is a familiar gravel drivetrain, hydraulic discs make sense on a bike this heavy and fast, and the Bosch system is widely supported.

The Grinder EVO still asks you to ride it like a bike. You shift, manage cadence, pick lines, and decide how much assistance you want. The motor gives you more options without changing the basic gravel-bike setup.

The similar names hide a pretty big difference:

The Grinder EVO Lite is almost the opposite interpretation of an electric gravel bike. BULLS lists it at roughly 36 pounds, with a Fazua Evation motor, a 255Wh battery, a carbon fork, a Shimano 105 drivetrain, and assistance up to 20 mph.

That 16-pound difference is significant. If you’re coming from a traditional gravel or road bike and want the e-Bike part to stay as subtle as possible, the Lite makes more sense. The Bosch Grinder EVO goes the other direction. The larger battery, suspension fork, and 28-mph assistance make more sense for longer outings, rougher gravel, steeper climbs, and commuting.

These aren’t two trims of the same bike. The choice comes down to whether you value lighter weight and a more traditional gravel-bike feel or more motor, battery, and suspension.

The Grinder EVO gets more interesting the less predictable your route becomes. It’s easy to ride for a fast commute during the week and a 50-mile mixed-surface ride on Saturday. A bike path can turn into gravel. A gravel road can dump you onto pavement. A long climb can show up when you’re already 30 miles from home. That’s where the combination of drop bars, 40mm tires, suspension, Bosch power, and a 500Wh battery earns its keep.

I’d look at it for:

• Long mixed-surface and bikepacking rides that combine pavement and gravel
• Fast commuting with rough-road or dirt-road options
• Riders who want drop bars but more comfort than a stiff road e-Bike
• Anyone who likes building routes instead of sticking to one type of terrain

I’d look elsewhere if nearly all your riding happens on smooth pavement. In that case, the suspension fork and 40mm tires are probably more bike than you need. And despite the fork, this still isn’t an e-MTB. Technical singletrack, larger rocks, drops, and rough trail descents call for more suspension and different geometry.

The Grinder EVO has enough going on mechanically and electrically that a professional inspection is important. That’s why every e-Bike Upway sells goes through a 50-point inspection. Its online listings include bike-specific information such as model year, mileage, frame size, battery details, drivetrain components, overall condition, and inspection findings. Upway also diagnoses the battery, motor, and display, repairs or replaces components that don’t meet its standards, updates software when applicable, and completes a test ride and final quality-control check.

That takes a lot of the guesswork out of comparing used bikes. Two Grinder EVOs with similar mileage can have very different histories, and knowing more about the battery and mechanical condition is considerably more useful than trying to make that call from a few marketplace photos.

Certified pre-owned e-Bikes also include a 1-year warranty and 14-day test ride policy, offering another layer of protection when you’re buying a used Bosch-powered e-Bike.