Wednesday, July 11, 2018

Getting AMP'd on e-Mountain Bikes

Full suspension e-mountain bikes have really come around in the last season or two, and I just took out the brand-new 2019 BMC Trailfox AMP for a first trail ride.

My normal trail bike is a Giant Trance Advanced, so with 140mm rear travel and a 150mm RockShox Revelation up front, the 150mm TrailFox should offer a pretty comparable ride. It’s close to twice the price of my SLX-equipped carbon bike at $7500, but it also has the new 250-watt Shimano STEPS MTB E8000 motor, a 500 Watt-Hour battery, Fox Float 36 fork and Fox Float DPS shock, and a Shimano XT drivetrain, so the price tag is pretty well justified.

I really wanted to go for a mountain bike ride, to ride the way I normally would on my own bike, but I also wanted to maximize the vertical potential with a little help from the STEPS motor. So I went to a nearby trail system with a few small mountains, wore my normal trail riding gear, and ran Strava to see how the ride measured up to my normal efforts (but as a private ride so I didn’t piss off all the top downhillers, XC climbers and local pro roadies with KOM’s on the trails, paved mountain climbs and gravel roads in the area). I’m specifically not spelling out where I rode since the rules, laws and recommendations surrounding Class 1 electric motor/battery pedal-assisted bicycles are still gray and murky – something I will get back to later in this blog.

This is a review specifically of the new Trailfox AMP 2, but also a comparison of this bike to the Specialized Turbo Levo Comp 6Fattie ($5,600) and the Giant Full-E+ 1 SX PRO ($5,200). And last, but not least, this is also a review of the current state of pedal-assisted full suspension bikes versus the current crop of human-powered full suspension bikes.


Right out of the parking lot I spun up the paved access road that reaches grades up to 18 percent without the heart pounding trauma that getting out of a car and immediately riding up an 18 percent grade normally provides. Hopping onto the technical, rocky, rooty singletrack on a milder uphill slope the power assist really sprang to life, turning a normally frustrating rock field into more of the feel of a fast, technical, mildly downhill section. In truth, it felt a little more like a video game than real life. 

The Shimano STEPs motor is a little different from the Specialized and Giant motors. It doesn’t have as much punch when the drive kicks in, but winds up like a little bit of turbo lag that is actually helpful in the New England singletrack. The power kick-in and shut-off when you start or stop pedaling doesn’t throw you quite as much as especially the Specialized motor. On the Giant Full-E, with five power-assist levels with a toggle button right next to my left thumb, I usually use the levels in a similar way to a shifter, especially when climbing. The Trailfox AMP uses a Di2 flatbar shifter to shift up from off to Eco to Trail to Boost, but I found that Boost was way too much for most climbs and left it in Trail or Eco for the most part, punching it up to Boost only on less technical climbs or some of the flatter, rough fire road sections where it really helped keep me near the top end velocity over speed-sucking rocky, rooty terrain.

Taking the steep switchbacking trail up to the big peak is normally a gut-busting experience, gasping for oxygen and normally dabbing here and there mainly because of fatigue. With the AMP it isn’t about power as much as it is about control – breathing is a controlled aerobic pace like a jogging at a moderate pace and finding the proper rhythm and cadence and clearing roots and rock obstacles with your pedals while continuing to turn your pedals to keep the power-assist on is the name of the game. Cadence is wicked important on all trail e-bikes. In order to keep sufficient power to the back tire you need to keep the cadence way up in a road-bike range: 80-110 rpm. Normally on a mountain bike climb my cadence can dip down into the 60-70 rpm range, with sudden bursts of power ample to jump a 25-30-pound mountain bike up a tricky technical section. On an e-bike, with its 500-watt motor only equating to less than one horsepower, the engine bogs down quickly when your cadence dips and it is trying to push a bike that weighs at least twice as much up a gradient. Keep your cadence up however, and even in Eco mode the motor kicks in and you can feel the strong pull up the trail.

Ridewise, I went up over the “big” mountain, down the other side, up and over the second peak, up and over the third, then back up and over the second and back up to the “big” peak. On my trail bike, this would have been a full ride, and I would have headed back down to the car and headed home. In fact, I did almost this exact same ride a week later on my Trance, and had a great, satisfying hour and 45-minute ride before work.

On the Trailfox AMP, however, I was just barely an hour into this ride and nowhere near ready to be finished. So, I took a fun long downhill off the side of the peak down to the lowest parking lot 130 vertical feet below the base of the mountain where I had parked. From there it’s just over 500 vertical feet up over 2 miles: a steep gravel road climb back up to the mountain base and then a paved access road switchbacking all the way up to the summit. Not the world’s biggest climb, but it’s our little neck of the wood’s Alpe d’Huez: just as steep as the famed French climb, but only about a quarter of the length. I locked out the suspension and pushed it hard, trying to see what this 50+ pound full suspension bike could do on a road climb. Quite well it turns out! Faster than roadies I can’t compete with on my road bike. Faster than Ted King’s fastest posted Strava segment up the mountain. Faster than anyone has ever gone up that road while plugged into Strava! The only person with a faster time up the paved access road was a guy whose ride was titled “Shuttle Runs” - so someone did go up that hill faster than me, but his bike was in a pickup truck when he did it, and even then, he only beat me by a few seconds.

Back up top and barely winded, I looped around the peak and headed down my original switchback singletrack. Soooo much fun! One added aspect I hadn’t expected was that I garnered several PR’s on downhill Strava segments on this ride. Not by big margins, but just a second or two here and there. The Trailfox AMP is a fantastic handling endure-style bike in its own right. The Fox 36 fork and Fox Float DPS rear shock worked flawlessly and felt plenty stiff. The added weight of the battery and motor in the downtube and BB section of the bike added a centered stability that made the bike feel capable of more speed, and though most of my downhill runs were well above the 20-mph governor on the bike, the ability to “gas” it out of turns with a few pedal stroke shaved just a little off my time. I have felt the same phenomenon on the Giant Full-E on an uphill/downhill run at Bear Brook State Park, where I shaved over 45 seconds off my Trance time on the Big Bear Downhill, a downhill-oriented trail with lots of pedal sections and twisty, tricky slow/fast sections. The ability to get back up to full speed out of corners shaved nearly ¼ of the time off the run!


Back to the car at the parking lot 9.5 miles and 90 minutes into the ride I was at the point where on a normal person-powered ride I would probably head back home. But with half a tank of battery left I decided I wasn’t nearly done. Dropping down into the other side of the trail network across the street from the mountain side, I rode a fun singletrack trail with loads of short, steep, technical ups and downs, twists and turns. I ended up taking about the same amount of time as I do on a fast non-powered ride: I easily cleared some technical sections that I hit just right, but bogged down on some others that I screwed up or that the added speed bounced me a little off my line or off-balance and off the bike. If I ride the same trail a few more times I feel like I should be able to clean most if not all the technical bits at a higher speed.

Nearly eight additional miles later I was making the final climb when the battery flashed low and the motor dropped down into Eco mode and I made it back up to the car on figurative fumes.


18 miles and 2800 vertical feet in 2 hours and 42 minutes.

Physically, my legs felt better than normal, but I was worked. Upper body took more of a beating than a normally-aspirated ride. Several lower body muscle groups felt oddly worked, and I felt as spent overall as the empty battery. The ride took a lot more psychological work than normal. Everything just comes at you so much faster, and you need to absorb, analyze and react to things a bit quicker than normal.


Pedal Assisted E-Mountain bikes are obviously a new phenomenon, and they have opened a Pandora’s box of issues surrounding trail access just the way any new user group encounters resistance. I picked up snowboarding in the mid-1980s. At the time snowboarding was only permitted at a handful of ski mountains in the USA, and I remember being forced to take a competency test at Pico Mountain in Vermont before they would allow me to get on a chairlift. The mountain e-bike takes an additional wrinkle in that it is motorized, and it is a bicycle. According to NEMBA (New England Mountain Biking), e-mountain bikes are too close to motorcycles for them to support. Their position is that everything we have gained for mountain bike access is based on the premise that mountain bikes are human-powered and a distinct user group from motorized groups. If we lump e-mountain bikes in with mountain bikes we could lose all kinds of current mountain bike access that we now enjoy.

I am pretty conflicted in this debate. While I agree that mountain bikes are not the same as motorcycles and enjoy the hell out of riding my mountain bike, I also don’t think that Class 1 pedal assisted e-mountain bikes are the same as motorcycles either. A Class 1 bike is limited to 20 mph top speed, has less than 1 horsepower, and is classified as a bicycle. It doesn’t have a throttle and if you don’t pedal you don’t go anywhere. When you do pedal you just feel like an amped up version of yourself. IMBA (International Mountain Biking Association), the world’s largest mountain bike advocacy group, just altered their stance in November 2017 to include support for allowing Class 1 e-bikes on trail systems "when the responsible land management agency, in consultation with local mountain bikers, deem such eMTB access is appropriate and will not cause any loss of access to non-motorized bikes." People for Bikes has a good website that gives a good overview of the state of eMTB's in all 50 states.

Sure, there would be some adjustment to the added speed (especially uphill) that multi-user trail systems would experience, but I also don’t see e-mountain bikes creating more trail destruction or erosion than regular bicycles, and I would say that on this 17-mile trail ride I didn’t create any more damage than I would have on a regular ride, except to say that I rode close to twice as far as I normally would have. I didn’t burn out or tear up trails – there simply isn’t the torque and power in a Class 1 pedal-assisted bike to do so, and I would be happy to go for a ride with any trail administrator on these bikes so that they can experience this firsthand.

As someone who runs a bike shop I definitely see this as a potential growth field in terms of sales. I’ve also seen how these things can literally change someone’s ability, like Brian Hall, a customer of ours, who has spent the last forty years living with Parkinson’s Disease. After years of struggling on his Specialized Enduro he is now having his own personal renaissance on his Turbo Levo and loving every minute of it. He is clearing climbs that he hasn’t been able to in years and is back to riding with friends, finishing steep climbs, and having a blast.

“It levels the playing field for a non-able-bodied rider” says Brian. “Before, when I rode a normal mountain bike it was like my friends had to ski with their kids. I couldn’t keep up. Now that’s not an issue any more.”

“In my opinion, it’s all about freedom. To a rider such as myself, freedom and accessibility means the world! I don’t ever want to stop moving. Riding my Levo will keep me moving and riding longer and further than a regular bike ever could.

It will definitely be interesting to see where this goes. According to NEMBA there are only two places in the commonwealth of Massachusetts where these are allowed. Some other areas in New Hampshire and Maine are much more ambivalent or the rules are murkier, and I think that some constructive planning and spelling out of rules and restrictions would be a step in the right direction.


The Trailfox AMP is a fantastic mountain bike and seems to be an evolution over e-mountain bikes that have come before. The Trailfox AMP 2 is the sweet spot in terms of price to benefit (BMC offers the 1 with Di2 in the USA and the LTD at over $12,000 in Europe). BMC also offers the Speedfox AMP with 120mm travel and more of a trail geometry at $5799.00 with the same motor and battery. We have a medium and large Trailfox AMP 2 demo bike in stock and Speedfox AMP’s for sale in the store. For a more budget-minded eMTB option, there is the Giant Dirt-E hardtail starting at $2600.00.

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