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Trek Fuel EXe 9.9 XX1 AXS Review

Alex Boyce
By
Alex Boyce,
E-Bike Reviewer
robb dorr
By
Robb Dorr,
Co-founder

40 mi

RANGE

20 mph

TOP SPEED

2.5 hrs

CHARGE TIME

40.5 lbs

WEIGHT

Mid-drive

MOTOR TYPE

Sponsors keep us charged up

Ideal for...

Fit riders
All-mountain trail riding
Highly invested riders or athletes who want the best of the best

Trek Fuel EXe 9.9 Review: Overview

Timing is everything and Trek has gained a huge advantage by being one of the first companies to release a TQ HPR50 motor-based e-MTB, the Fuel EXe. Some clever engineering and the very best component package have made something that is worth trying and buying for the right user.

The Fuel EXe is a lightweight e-MTB, with Trek hoping its style and specs will be appealing to the non-motor powered MTB public as they bring to market innovative products.

Based around a carbon frame with 150 mm of suspension travel and 29” wheels the Fuel Exe is almost indistinguishable from its non-powered sibling. We viewed one standing next to the Fuel EX and it is very hard to tell the difference at first glance to the untrained eye.

There are a number of design elements that give the rider the visual sensation they are riding an unpowered bike, firstly the down tube is virtually the same size as a normal bike, despite the fact, there is a battery hidden away. The bottom bracket area as well is particularly slim considering there is a motor implanted in it.

Trek Fuel EXe 9.9 XX1 AXS
Credit: Nicolas Boyce

The Fuel EXe has been designed as a trail bike so it has that feel to it when you pick it up. The carbon wheelset and low rolling resistance tires also lean in that direction. There are no cable farms on the cockpit, it’s all wireless apart from the power remote and brakes, the RockShox suspension and Bontrager wheels have wireless settings as well for pressure tuning. The display is flush with the top tube and looks very clear to read. The fact that the bike is electric does not detract in any way from it aesthetically.

The trail category of e-MTB has been slightly forgotten or gotten significantly blurry over the years in the media as we focus on “big rigs” with huge suspension travel, so taking the Fuel EXe for a ride is a calming experience. It also highlights why the lightweight e-bike category works so well for this type of trail riding. Easy going trailing riding with fitness as a goal. This type of riding is not well suited with a big heavy bike even from a philosophical point of view, so it’s perfectly understandable that there was resistance to the use of e-bikes in this realm from the core of MTB a few years ago.

Best For

If you are a fit rider and want the benefits of an e-mtb in a true MTB package, this is the bike for you. It’s the top product available on the market, it’s almost wildly expensive. This is meant for All-mountain trail riding, not wild rough rocky Enduro trails. We would easily choose this bike to be in our quiver if we could.

Reasons to Buy

  • If you want absolute top before hitting the custom bike world.
  • You need AXS and wireless everything.
  • Carbon is your material.
  • You are fitness led.
  • Money is no object, or you are a dedicated pro athlete.

Things to Consider

Trek is one of the top bike brands in the world, so this is pinnacle engineering, it looks amazing in reality but we recommend using it as is, don’t fit longer travel suspension.

Trek Fuel EXe 9.9 Components

The Fuel is the absolute top-of-the-line, starting with a carbon frame, suspended by a RockShox Ultimate fork and the top-of-the-line RockShox Super Deluxe Ultimate shock in the back.

The drive train is SRAM’s XX1 AXS, which is functionally exceptional and precise to use as you zap through the gears using the tunable remote, you can set the function buttons exactly the way you like for shifting according to your preference. It has 12 speeds and is very smooth, also the power runs off the main bike battery.

Trek Fuel EXe 9.9 XX1 AXS Disc Brakes
Credit: Nicolas Boyce

Braking is taken care of by SRAM’s Code RSC brakes on G2 discs, again top of the line, the bike does exactly what you want it to do instantly when stopping. You can tune the lever to whatever feel you might like, either soft or hard, and also long pad movement or short.

The wheelset is the most frictionless feeling wheelset we have used for years, rolling resistance is at an absolute minimum. This efficient ride quality gives an absolutely precise and very stiff feeling when changing direction on the trail. The response to rider input can not be better.

It doesn’t finish there, the RockShox AXS seat post which is wireless (although, strangely, it feels like it’s directly connected), is great and allows the perfect saddle position to be found at all times and has enough travel so that the stand over height of the frame is able to be set low. The bars are a one-piece design with maximum integration and have a very good sweep, roll angle, and rise pre-set that will appeal to all for this type of bike. Also, there is a tool in the headset for making changes on the fly, so you don’t have to hunt around in your backpack.

Finally, the Airwiz system on the suspension and tires allows you to measure and understand your ideal riding setup via the AirWiz app, meaning that tuning the bike to a very precise point is possible every time you ride and you can also be aware if you have a slow-leaking puncture.

TQ Motor and Battery

The TQ HPR50 motor is a 50 Nm motor with a pinion ring design that allows it to be very compact for its power rating. The “pinion ring” is where you have one offset sprocket moving inside another. The motor kicks out 250w and uses a 360Wh battery plus range extenders which can be plugged into the bike and sit in the bottle holder. All this is controlled by an integrated display and discrete handlebar remote. The battery can be removed for off-bike charging, although we didn’t need to, and is good for about 3-5 hours of riding according to the power mode used and rider fitness.

Trek Fuel EXe 9.9 XX1 AXS Hub
Credit: Trek

The power delivery is smooth and exceptionally silent, being the quietest central motor on the market. You can not hear it when you ride, it’s totally silent. Importantly because of this small motor with strong power levels, the actual frame design has been done exactly the way the designers wanted, they did not have to design the geometry around the motor system, they could design the bike as they wanted with no compromise.

The power support levels, in our experience, are a level or slightly below a full-powered class 1 e-bike. The Fuel EXe’s top power mode is equivalent to a medium, softly tuned, EP8 Shimano medium power mode. So this is not a bike for riders who want to use turbo or boost all day. The power delivery is soft and flawless when it transitions past the assist speed limit (20mph). It is hard to know when you are actually using the assist as the software tune is one of the most rider/system-integrated tunes we have used. The bionic mix of rider and machine is incredibly impressive.

Trek Fuel EXe 9.9 XX1 AXS Smart Phone App
Credit: Trek

The motor power can be tuned via an app that connects directly via Bluetooth to the bike. The display is very easy to read, monochromatic, and clear with one function button which is used to turn the bike on and cycle through the different display options. The display is sunken into the top tube and is therefore subtle in its presence. The remote is on the left side of the bar and fits well with the other controls around it.

Geometry

The geometry points for suspension and frame layout are also the same as the non-powered version. We are not repeating marketing information, on direct observation, it’s actually a fact.

The bike with 150mm of travel up front and 140mm on the rear is exactly right with this geometry. It doesn’t need to be updated or changed to bigger travel as some have done, as there will be a mismatch with the motor power. We have learned as well that TQ will be working on a more powerful motor for those who want a lightweight TQ-powered e-bike with longer travel. So wait for that if you don’t want a trail-centered e-MTB. This is not designed for flying through rock gardens.

Trek Fuel EXe 9.9 XX1 AXS
Credit: Nicolas Boyce

The pedal position is very modern with the rider centered forward on the steep seat post tube this gives a pedal action more rearward compared to older designs. The rider will then find themself in a more forward position with their weight centered over the bars. Thus cornering will be a more evenly weighted experience as the rider uses the front wheel in corners more effectively. You will get more responsive steering and effective pedal energy transfer with this layout.

Trek Fuel EXe 9.9 Review: Takeaways

On board the Fuel the trail glides very quietly by, as you click the buttons to change gear there is just a very quiet electronic zap as the chain shifts, this is actually what trail riding should be. If you want to explore farther afield the rider can carry a few extender batteries on the bike or in a backpack, which look like water bottles, therefore range is not really an issue especially if you are fit. The experience is definitely that of a trail bike.

Trek Fuel EXe 9.9 XX1 AXS
Credit: Nicolas Boyce

The Fuel EXe is very smooth and the motor gives exceptionally well-integrated rider/machine support. It’s hard to know if the bike is on as it’s so quiet when riding.

This is not a sofa to sit on with vague steering. The 64.8 degree head angle reflects this as well as the bike corners very directly. The central position on the bike gives the rider enough latitude to move around the frame without upsetting the ride balance in technical conditions. So if you make an error you won’t be punished for it.

The lightweight of 18.5 kilos (40lbs) means the bike will respond to what the rider wants, not the other way around. This makes it slightly less forgiving than a heavyweight e-mtb but way more maneuverable on descents, allowing you to ride it in the same way you would a normal MTB. The 150mm suspension travel is an excellent choice for balancing needs and pedaling efficiency.

You will love your time onboard, it is our favorite bike in this category in the last year.

Price

This is a very high-end bike, it costs around $14,000 which is getting on to be one of the most expensive bikes on the market. It does though have versions that start at around $7000 which will preserve your sanity somewhat, but for those that must have the best, this is it and you must pay for it.

Range

Lightweight e-MTBs don’t mean zero range, this battery is tuned for less torque and therefore is comparable to a full-power e-MTB, however as the rider’s fitness has more significance on this type of bike, we recommend getting an extra range extender if you are nervous and want to use the motor power more than leg power.

Other Bikes In The Range

The Fuel EXe 9.5 starts at $6499 which uses the same frame, just lesser componentry that will change the ride feel.

This is actually for a lightweight e-MTB a very competitive starting price compared to the rest of the market.

Ratings

Power
3/5
3

This bike is not designed to be powerful, it’s designed to be light and perform like a normal MTB, with enough power to stop your legs burning on hard climbs.

Range
5/5
5

We would actually give this a limitless range as the pedaling resistance from the system when the motor is turned off is virtually zero. This is not the norm with most e-bikes.

Comfort
5/5
5

This bike for a real mountain biker has good components and the rider can find their ideal position and suspension setting with ease. Use the app to tune your suspension and adapt it according to use, guided by your SRAM digital assistant.

Durability
5/5
5

During our time on the bike we noted no noticeable problems and we even heard back from TREK that updates had been made on any niggles that we had mentioned.

Style
5/5
5

We don’t like to attract attention when we ride even though a bike like this will do that, riders around us looked carefully and stayed silent and you could see that they were thinking very hard about what we were riding. Maximum style. Have you SEEN the yellow paint?!

Our Research Methodology

We personally research and test every e-bike featured in our reviews and guides to provide accurate, data-driven recommendations. Learn how we review.

About Our Editorial Team

Alex Boyce
Written by Alex Boyce
E-Bike Reviewer
Alex Boyce has been in the bike industry in various roles since 2008, he has tested more than 400 bikes over the years and created content for magazines and media outlets the world over.
robb dorr
Edited by Robb Dorr
Co-founder
Robb is a massive cycling enthusiast who has more than 20 years of non-motorized cycling experience. He started eBikes.org to lower the barrier of entry to cycling and reduce the intimidation people can experience when getting into the cycling world.

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