Do Kids Need E-Mountain Bikes?

Rarely has a piece of test gear caused so much controversy in our household. Ski boots, bikes, fly rods, camp showers—all manner of gear lands on my doorstep for review, and my husband and ten-year-old daughter greet every item with curiosity. But unboxing the Woom UP 6 ($3,749), an e-mountain bike for kids, triggered emotions ranging from anger to elation.

My daughter, Simone, the bike’s intended tester, cooed over the gleaming blue finish on the UP’s aluminum frame, the 90-millimeter air fork, the Schwalbe Rocket Ron tires on 26-inch wheels, and the Fazua motor–battery unit that boosts pedal strokes with up to 250 watts of power.

My husband, Ben, was less enthusiastic. He hates it when speedier e-bikers buzz past us on paved bike paths and uphill stretches of singletrack around our home in Steamboat Springs, Colorado. “I don’t want her becoming one of those assholes,” he muttered.

Safety is another consideration. Commuter e-bikes have become increasingly popular among our local tweens and teens, who fit onto the smallest adult frames from companies such as Haibike, Pedego, and Trek. Fitted with panniers and racks, e-bikes let kids pedal themselves to lacrosse practice or violin lessons. But they’ve also elicited concern: Isn’t it dangerous to hand out motors to people with undeveloped prefrontal cortexes? Around Steamboat, it’s become common to see kids zooming their motorized cycles down the middle of the street or crowding several of their helmetless friends onto the handlebars and top tubes.

Now brands are starting to manufacture kids’ e-mountain bikes. Haibike makes the child-size Sduro HardFour ($2,710), with 24-inch wheels. Commencal sells the Meta HT 24 Power ($3,000). And this month, the Austrian kids brand Woom launched its e-mountain-bike models in the U.S. The UP 5 ($3,599) has 24-inch wheels and fits seven-to-eleven-year-olds; the UP 6 ($3,749) features 26-inch wheels and fits ten-to-fourteen-year-olds.

Despite our obvious apprehension, I was intrigued by the idea of an e-mountain bike for Simone. Her dad and I have always invested in top-quality kids’ bikes in an attempt to help our daughter love mountain biking as much as we do. Wanting to increase her chance of success on the trails and minimize any undue suffering, we’ve sought out the most lightweight builds (most kids’ bikes are way too heavy for them to pedal for any real distance) and we’ve insisted on models with geometries and components optimized for children’s proportions. Why not extend that continuum of optimization to e-mountain bikes, I reasoned, given their potential to boost my child’s pedaling power?

To be sure, Simone’s first ride around the neighborhood on the Woom UP 6 made her giddy with elation. “It exhilarates so fast!” she hooted, mistaking exhilarates for accelerates. I didn’t correct her, because she was right on both counts.

The UP 6 lets riders choose from three levels of pedal assistance, adjustable by pressing buttons located on the top tube. Colored lights indicate the three modes, with blue for the least motor support (100 watts), green for medium (200 watts), and pink for the most powerful (250 watts). Even in blue mode, she reached cruising speed over flat terrain within just two or three effortless pedal cranks.

UP’s factory settings turn off the motor’s pedal assist once the rider has reached 12 miles per hour (well under the 20-mile-per-hour limit for Class 1 e-bikes). That makes it easier for her to get started from a stop, or to ride uphill, but it doesn’t make her fast overall—not on pavement, at least. I can still keep up with her and even leave her behind on my cruiser bike. She’s just speedier off the line.

On dirt, though, the UP zooms her way out ahead of me. Our first off-road ride with the UP 6 was at an e-bike-friendly singletrack network in the nearby town of Oak Creek. Our uphill route included a mix of steep dirt paths and two-track lanes that showcased the bike’s advantages. Simone pedaled easily up the hills, stopping now and then to wait for me as I crawled along in my granny gear. “I feel like a show-off,” she fretted.

“Are you using the blue setting?” I asked. “No, the pink,” she admitted. “I can’t help it. It’s so fun, not feeling out of breath!” The motor support had already turned her into an addict. But at least she was a happy addict: on her regular bike, she would’ve been complaining about the effort or settling into grim resolution.

Weighing 37 pounds, the UP 6 is heavier than many kids’ mountain bikes (Simone’s Trailcraft Pineridge 24 weighs 23 pounds). But as an e-bike, it’s quite light, compared with the 41-pound Commencal Meta HT 24 and the 44-pound Haibike HardFour. That’s because UP takes many of its build cues from Woom’s nonelectric frames, which feature feathery aluminum and typically rank among the lightest available options for each rider size.

Even so, Simone actually enjoyed the UP’s heft once we stopped climbing and tipped our bikes downhill onto rock-studded singletrack. There the bike felt more stable than her lightweight rig. “I don’t feel like I’m getting bucked around as much,” she reported. We’d adjusted the 90-millimeter air fork to her preferred settings for compression and rebound damping, and the suspension did an admirable job of soaking up both slow- and high-speed hits.

The Promax hydraulic disc brakes (with a 160-millimeter rotor on the front and 140-millimeter rear) let her modulate her speed on steep descents and rock rolls that required precise braking to avoid skidding out. The grips, saddle, and pedals are all sized down for smaller riders, so they felt comfortable for her. And the SRAM NX1 drivetrain and trigger shifter earned her approval for responsiveness.

The UP 6 frame is also more streamlined than many e-bikes, which are often ridiculed for having down tubes so bloated with batteries that they look pregnant. The Fazua’s seven-pound battery-motor unit is slim, and so sleek in its integration that most passersby assume it’s a regular bike, not an e-bike.

The unit is removable for easy charging, which takes about four hours. Woom is still computing the hours of ride time that users can expect on each pedal-assist setting, but the company estimates two to three hours on pink mode (full power) and five to eight hours on blue (lowest power). We charge it about once a week and get six to eight rides of varying duration out of each top-off.

So far I wouldn’t say that the UP 6 has made Simone a better rider. She was already a strong mountain biker who hammers technical terrain with balance and agility. But the UP 6 does keep climbing from feeling like a kick in the teeth, and that’s enabled us to notch a bunch of family rides that would’ve been too grueling or too far for Simone to complete on her regular bike.

One Saturday, we circumnavigated a nearby reservoir on a 16-mile network of dirt roads and gravel paths, which never would’ve happened without pedal assist. The following day, when my husband and I suggested extending our singletrack ride with a spur trail that added two miles of climbing, we heard zero complaints. (Usually, something like that would require major cajoling or bribery.)

Thus we have come to love the UP. Even my husband tolerates it with grudging acceptance, because none of the feared e-bike behavior has come to pass. Simone is a sensible kid who has declined to load un-helmeted friends onto her top tube. And the only people she buzzes on the uphill is her parents. We indulge her.

However, this e-mountain bike can’t fully replace her regular rig, for several reasons. One is limited access. Most of our local trails are closed to pedal-assisted bikes, so if Simone wants to ride there with us or her friends, she still needs an old-school lung buster.

But even if she could ride her e-bike all the time, Simone wouldn’t want to. Through testing, Simone discovered that triumph doesn’t come without maximum effort. “The rewards feel better when you work for them,” she told me as we pedaled home from one recent ride (the UP is too heavy for me to hoist onto our cartop bike rack). It turns out that deadening some of the pain of mountain biking also dims some of the satisfaction. In other words, the e-mountain bike seems to offer a middle-ground experience that’s almost always pleasant and enjoyable but not always the most invigorating.

For a kid, that’s rad. It gives Simone an alternative to battling dragons on her bike and affords her enough energy to notice the view. That’s why we’re willing to make room for a second kids’ bike in our garage. The UP is the rig Simone reaches for when she just wants to have fun, rather than mining every ounce of her determination and strength. Yet it also stretches her riding horizons in really neat ways. I can’t wait to take it to the Slickrock Trail in Moab, Utah, where I expect it’ll give Simone unprecedented ability to conquer those ridiculously steep slabs of sandstone. Maybe I’ll Rochambeau with her for the chance to try it there myself.

For those that ride less singletrack than Simone typically does, the UP seems like an ideal quiver of one, because it supercharges a kid’s desire to ride. Simone used to hop on her bike from time to time to go play with a friend or accompany me on errands, but now she’s inventing missions that might require an e-bike ride. “I think I’ll go see if anyone’s at the park,” she announced the other day, without any prompting from me. This bike is already growing her sphere of independence.