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Long-term review: Trek Fuel EXe shifts the standard for eMTB

Nearly silent and so fun to ride

Electric mountain bikes are rapidly maturing, in design and technology. When Trek launched the EXe, the lightweight eMTB with its TQ motor represented a big step forward in what was possible for the electric category.

I was really impressed with the EXe out of the gates. After spending several months on Trek’s new bike, that hasn’t faded in the slightest. Here’s what makes the EXe so great, where it could improve as well as what to expect – and what not to expect – from this lightweight eMTB.

We covered a lot of details about what set this eMTB apart when the EXe launched and there is a lot to cover in the review. So for details on the bike, hit the launch. For details on how it rides – which, really, is the important part – read on.

Review: Trek Fuel EXe

The EXe follows the design of Trek’s new Fuel EX closely. Very closely. Or, rather, leads that design, since it was released first. Both bikes feature 140mm of rear wheel travel with 150mm front suspension, modern (slack, low, long reach) geometry, but with efficient suspension that keeps the bikes quick and snappy on the trail. The ability to run a 27.5″ rear wheel with the 29″ front gives the option to make the bikes even more playful in corners and controlled on steeps. The main difference, other than a drive unit, is that the EXe only has a Mino-Link while the EX has several other geometry adjustments.

Honestly, the EXe is really fun to ride. It’s quicker and nimbler than any other eMTB I’ve ridden. It is way closer to the easy movement and balanced weight of a full-powered mountain bike than any electric bike on the market right now. You don’t have to hit the gym before you ride if you want to pull the front end up for mid-trail manuals. You can actually move the back end around with ease, instead of forethought and effort. Basically, all the skills you have on a normal mountain bike transfer over with little to minimal adjustments. You just also get a motor. One that is so small, it sometimes took people a while to realize I was on an eMTB.

TQ HPR50: The little motor that could

The heart of Trek’s EXe is TQ’s HRP50 system. The German brand takes a completely different approach to motor design for bikes and it changes the game. It doesn’t render larger motors irrelevant, but it makes a different kind of bike possible. To start with, the harmonic pin ring transmission is light. The motor weighs just 1.85kg and, with a 360Wh battery and controls, the entire system weighs just 3.9kg.

TQ’s HRP50 is also much smaller. Small enough that, when I ran into other riders in the woods, it often took them a while to notice I was on an electric bike. The wider downtube on the EXe is more of a giveaway, really, than the diminutive HRP50.

Finally, the harmonic pin ring transmission design is quiet and smooth. Really, the only downside, compared to traditional eMTB at least, is that it only carries 50Nm of torque. For many, though, that will be all the support you need, or want, from a mountain bike.

Trek Fuel EXe review - TQ HRP50 motor
The TQ disappears behind a chainring and is still sly from the non-drive side.
Sound of silence

I don’t need a fancy graph or sciencey words like “tonality” to tell you that the EXe is quiet. It’s barely perceptible unless you’re in the highest support mode. Even then, it’s quiet. That’s when I was riding the bike for review purposes, so I was intently focusing trying to hear the bike. I verified that it was actually quiet by riding with a few analog friends. They confirmed they rarely noticed any noise coming from the motor.

Sounds that are louder than the motor include, but are not limited to: the tires, when rolling on basically any surface; the Line Pro 30 hubs freewheeling; the AXS shifting; the sound of wind in your helmet; casual conversation. Bottom line, the TQ HRP50 does make a noise, but you have to be paying attention to notice it.

Power and poise

The TQ doesn’t just sound good, though. It feels good to ride. Every rider will have a different idea of what a “natural” assist feels like, but the TQ tops the ranks in my books. It’s far and away better than any other drive unit when pedalling out of the saddle, delivering smooth and consistent power without surges. That’s the same for pedalling seated. The HRP50 comes on smooth and tapers off in a way that feels similar to how you would lose speed on a normal bike. The power engages quickly, but without any of the jolt or kick of some higher-powered motors. With 50Nm of torque, you’ll still have to put in some effort to get the EXe up steeper grades, of course. But on all but the steepest trails, its an impressively smooth support that makes you feel like a fitter rider, not feel like you’re riding a mini-moto.

The only minor issue I had with the motor’s performance came when, during the odd time spinning the cranks through tight corners but not actually putting power down, it would stutter as it re-engaged. It would still engage just fine, but a half-second later than expected. This wasn’t every time, and it didn’t happen when I coasted or when I kept power on through the corner, but something about spinning the cranks seemed to confuse the system slightly.

All in all, the way TQ’s drive unit works doesn’t just feel better, it makes technical riding easier. You don’t have to factor in when and how the motor will engage as  you approach a root or rock move.

Trek EXe 9.9 AXS

Trek pulls no punches for the top-end EXe. There’s a few curiosities and fancy features exclusive to the 9.9 AXS. Most notably, the wired SRAM AXS rear derailleur. While there’s something ironic about adding a wire to a wireless derailleur, I’ll admit I loved having it automatically charge when I charged the main battery. The trade-off is that the bike needs to be turned on to shift at all. So if you run out of juice, or just want to shift down the cassette to take a wheel off, you need some power. The Rock Shox Reverb AXS, though, still uses its own battery.

Trek equips the 9.9 AXS with its carbon fibre RSL bar-stem combo and the carbon fiber Line Pro 30 wheels. In combination with the stout EXe frame, it is a very rigid build. This is great when you’re carving manicured berms. But I found it overly harsh, to the point of being tiring, on any sort of sustained rough trails. Switching out the bars or the wheels to more forgiving options helped take just enough of the edge off (I tried both, in various combinations. We Are One’s Convert wheels were just forgiving enough to balance out the EXe for my personal preferences) making the 9.9 a rocket ship, but one that I could control.

There are also TireWiz and ShockWiz gadgets built into the Line Pro 30 rims and the RockShox suspension. I’m neither here nor there on that feature. If you like it and use it, great. I’m not that particular, or that irregular with checking pressures, that I ever found it useful. But the Wiz’s didn’t cause any problems during the test period, either.

The only difficulty I had with the EXe was that, eventually, some bolts holding the TQ motor did eventually loosen off. That is with a complete lack of service or maintenance over weeks of hard riding, though. So the minimum of regular maintenance should prevent that from becoming an issue at all.

All this comes in for a shocking $18,300. That is comparable to what other top-end eMTB are going for but still a lot of money. If you don’t have that kind of scratch kicking around, the EXe 9.5, at $8,400, still features a carbon fibre frame and TQ’s mini motor.

Trek Fuel EXe review - TQ black-and-white display showing battery life
TQ’s black-and-white display is clear, easy to use and shows the information you need to know. Exact battery percentages are key with smaller batteries.

Lightweight eMTBs – Battery life, power, weight: choose two

There’s an old saying in mountain biking: “Light weight, durable, inexpensive: choose two.” The idea is that you can’t have everything you want, for free. A modified version for lightweight eMTB would be “Range, power, weight: choose two.” (Because, well, there’s no lightweight eMTB’s that could be reasonably described as “inexpensive,” yet). With the EXe, Trek deliver’s on weight and sacrifices a little on power and weight. Depending on how you like to ride, this bike either hits the sweet spot or leaves something to be desired.

Personally, I really like where Trek landed. It gets you enough support for a reasonably big ride – more than I’d do every day. It has enough power that  you can get a lot more out of your ride, without feeling like it does everything for you. And, most importantly, it feels more like a mountain bike than an electric bike than any other eMTB I’ve ridden at this point.

Trek Fuel EXe review

 

Range anxiety and riding with friends: where does a lightweight eMTB fit in?

To stick with the dime store philosophy, my family has a saying passed down (repeatedly) by one uncle in particular: “You can pick your friends, and you can pick your nose, but you can’t pick your friend’s nose.” What does that have to do with mountain bikes? Well, the mid-power, mid-range of the EXe might, depending on your friends, change group ride dynamics. Because you can pick your friends and how you ride, but you can’t pick how they ride. And you definitely can’t stop a friend on a full-power eMTB from hitting turbo mode and dropping you on a climb.

The problem is similar to the problem with all ebikes: one of power differences. Since lightweight eMTB’s are still relatively new, they’re also sort of exclusive. Can you ride with full-power e-friends? Or analog buddies? The answer to both is “it depends.”

Trek’s EXe is the first eMTB that is still exciting to ride with unassisted friends. Turn down the power to match the unassisted pace of your buddy and it isn’t quite like riding without a motor, but the feeling is actually really close. Just a bit easier. And, of course, it’s really quiet. Point downhill, and the sensations are, again, really close to what your freind is riding. That, on its own, will be exciting to any eMTB converts that have struggled riding with analog friends.

Trek’s EXe frame is built tough despite the bike’s light weight.

Riding with full-power eMTB is a different beast. If your friends are nice, you can keep up fine, but just won’t be able to cover the same distance. If your friends are a bunch of bros that just want to blast up the fireroad or steepest trail around to get to the top as fast as possible, you’re going to struggle to keep up. Either way, you’re going to be experiencing some “range anxiety” as you watch the EXe’s power bar deplete before full-battery friends even start thinking about conserving fuel. So, pick your friends wisely, because you can’t pick how they’ll ride.

That’s not to say the EXe doesn’t have enough range. It just doesn’t have the over-the-top range of some modern eMTB. With a 360Wh battery, Trek supplies enough juice to get through rides that would be big efforts without the assist. Exact range will vary by terrain and rider, of course. But, at roughly 80kg, I’d get over 1,000m out of a charge, regularly using full-power. After learning to work with the TQ a bit better, I could regularly get more.

That is a long-winded answer, admittedly, but it’s a question I think a lot of riders will be asking before pulling the trigger on a newer line of eMTB.

Trek Fuel EXe review
Trek Fuel EXe

Conclusions: Trek EXe and TQ shift the standard for lightweight eMTB

Trek has done an excellent job with the EXe, designing a mid-travel trail bike that fully takes advantage of the opportunities TQ’s small-but-powerful HPR50 creates. The EXe is capable of taking on all kinds of challenging trails, but its also light and snappy enough, for an eMTB, to be fun on a really wide range of trails.

I rode this bike a lot, over a long period and in a wide range of different places. And certainly a wider range of trail types than I’d usually take a full power eMTB on. That is, in part, because it made a wider range of trails fun. Since it is lighter, more maneuverable and more playful, the EXe is more fun on lower-angle, tighter trails than heavier bikes.

Trek’s also made it durable. This bike went through a week straight of big days in the Okanagan and, other than needing to tighten down a few bolts and a scratch to the paint, it came away clean.

The result was that it made the choice between pedaling and taking the assist a lot harder because, well, I knew it would feel more like a mountain bike when I wanted it to. Sure, I had to learn to live with a little range anxiety. Easily worth the trade-off for the performance of the EXe and TQ combo.

Trek EXe 9.9 AXS retails for $18,300 at Trek stores and online through Trekbikes.com.