It feels like cheating: The Trek Domane+ SLR9 gravel bike, reviewed

Enlarge / The Trek Domane+ SLR9 with eTap before an epic ride.

Eric Bangeman

One of the things I love most about working at Ars Technica is the lunchtime bike rides. My home in the northwest suburbs of Chicago lies two miles from the Des Plaines River Trail and about three miles from the North Branch Trail. When the weather cooperates, I’m generally furiously pedaling through the woods on my Trek Checkpoint ALR 5 gravel bike.

So when Trek offered me the chance to ride its top-of-the-line Domane+ SLR 9 e-bike, I jumped at the opportunity. Yes, the weather can be dodgy during seasonal transitions, but I’d be facing the changing temps and gusting winds astride a carbon-frame gravel bike with carbon wheels… and a 50 Nm electric motor paired with a 360 Wh battery in the downtube.

But even as I picked up the Domane+ from a local bike shop, one question kept popping up. Why would I want to ride an electric road bike?

I ride for a number of reasons. I enjoy it, I like being out in nature, I like riding with friends, and it’s fantastic exercise. The Domane+ would hopefully make the riding experience better, but I wouldn’t be getting the full aerobic benefit from my rides with a motor doing some of the work. Electrified commuter bikes, cargo bikes, beach bikes, and even mountain bikes have built-in use cases. But for a guy who loves burning calories on a bicycle, the existence of this $13,000 e-bike is something of a head-scratcher.

The Domane+ SLR 9 starts at $12,999. Along with the aforementioned Checkpoint, Domane is one of Trek’s two gravel bike lines. There are subtle differences in geometry between the two, but the main difference is that the Checkpoint comes with 40mm tires, while the Domane has 32 mm standard.

The top tube has a built-in display. You can see the boost buttons on the interior of the drop bars.
Enlarge / The top tube has a built-in display. You can see the boost buttons on the interior of the drop bars.

Eric Bangeman

A close-up of the boost buttons.
Enlarge / A close-up of the boost buttons.


As one would expect from a bike with this price tag, the Domane+ has been bedazzled with top-of-the-line components. Starting with the gear you’d find on a regular bike, this Trek has Bontrager Aeolus RSL 34 OCLV carbon wheels, Shimano’s top-of-the-line Dura-Ace Di2 12-speed wireless electronic drivetrain, 32 mm Bontrager RC Hard-Case Lite tires, and an LED display with Bluetooth and ANT+ connectivity built into the top tube.

At first glance, the Domane+ doesn’t look like an e-bike. With the battery parked inside it, the downtube is thicker than the non-electrified Domanes, and there are a couple of buttons on the handlebars for controlling the motor, which is located inside the bottom bracket. The difference is noticeable once you pick the Domane+ SLR 9 up: it weighs 25.91 lb (11.75 kg), nearly 10 lb (4.5 kg) more than its human-powered counterpart (and about 4.5 lb more than my aluminum-frame Checkpoint ALR 5).

The wireless shifting is almost flawless.
Enlarge / The wireless shifting is almost flawless.

Eric Bangeman

The 50 Nm motor inside the bottom bracket is powered by an integrated 360 Wh battery that can provide 250 W of power continuously, with 300 W of peak power. The Domane+ has three assist modes. Eco adds 75 W of power to your pedaling efforts, Mid gives you 150 W, and the High setting 300 W. With boosts up to 28 mph, the Domane+ is a Class 3 e-bike. Some states and municipalities have restrictions on Class 3 e-bikes, so be sure you’re aware of the laws where you live.

Built into the top tube is an LED screen that can display speed, battery level, estimated range, and how many watts you’re cranking out. As a bike computer, it’s rudimentary, so I purchased a phone mount. While that allowed me to ride with the Trek Central app open, which can show all the data you’d want on a ride, it also partially obscured the LED on the top tube.




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