The Trek Fuel EX 9.8 Trail Bike Knows the Best Hiding Spots [In for Test]

Any bike with a snack trough in the downtube is worth a look in my book. The Trek Fuel EX 9.8 has space for a jacket, spares, and whatever snacks you want to cram inside. Over the next several weeks It will be stuffed long before any hip belt or backpack.

While the Fuel EX floats on fairly neutral trail travel, with a 130mm rear axle path and 140mm at the fork, the bike’s geometry looks primed for a lot hotter party. With a 66° headtube angle in the low position, a 455mm reach on the size medium/large, and 437mm chainstays, the wheelbase is only 11mm shorter than the 160mm Megatower I am currently testing. That’s a lot of fun in a light package, and I look forward to sharing how it rips.

A 140mm Fox 36 fork seems almost overkill for a bike in this travel category, but Trek clearly knew that the geometry would entice riders to push it harder than their typical mid-travel trail bike. The frame will happily play with up to a 150mm fork. The rear damper is a Fox Performance Float EVOL, built around Trek’s RE:aktiv suspension specifications. When asked about shock selection, Trek frame designer Dylan Howes mentioned that “on the Fuel EX, we chose the 210mm size standard as it allowed us to design a shock that could fit the Thru-Shaft packaging we wanted, but also allowed the shock to be swapped out for almost any other 210mm shock to give both us and the customer options on shock spec or choice.”

The Fuel EX 9.8 build that I’m currently testing has a SRAM GX-Eagle 12-speed drivetrain, Shimano SLX 4-piston brakes, a carbon Bontrager handlebar, and a 150mm Bontrager Line Elite Dropper. The Bontrager Line Carbon 30 wheelset keeps the bike’s weight down, with the Fuel EX 9.8 hitting the scale at under 30lbs for the size medium/large.

After the initial descent, the only element of this bike that seems a little off is the tire selection. I prefer tires no wider than 2.4″, and these trail hugging balloons feel a little sluggish. I’ll leave them on for the first few weeks and see how it plays out. Maybe I just snacked too much before pedaling.

Update: Given the surging sales of Late, Trek had to sell this bike before I was able to complete the full review. Here are some ride impressions from the weeks I spent with the Fuel EX 9.8. 

To begin, the component spec is spot on. The carbon fiber rims give the Fuel EX a light and precise ride sensation, and the Shimano SLX 4-pot brakes are plenty strong for this bike’s intended use. All of the Bontrager-branded parts, from the seat post to the saddle and carbon handlebar function well and feel appropriately selected for everyday trail riding. The SRAM 12-speed drivetrain worked a treat, adding to the list of bits that won’t need an upgrade any time soon. 

The only caveat to my component praise is the tires. The Bontrager XR4 Team Issue 29 x 2.6″ tires are some of the least grippy rubber I have ridden in a long while. I rode the same trail a few times with these and another set of tires mounted on the Fuel, and the XR4 tread lost traction in multiple places where the other tires held fast. I managed to wash the front tire and injured a few ribs, so I’m particularly sore about their poor grip.  

Given the bike’s long and slack geometry numbers I expected it to feel like “more bike” than the travel numbers suggest. Instead, it felt like the short-travel, enduro-shaped machine that it is. I didn’t have any trouble finding the end of the Fuel’s descending capabilities on my local trails, some of which have been part of the Italian Superenduro in the past. The minimal 130/140mm of travel simply runs out on the rough stuff, leaving the ride feeling harsh. Adding air to the suspension only reduces traction further. Put simply, this bike is better suited to someone who descends with a little more finesse and patience than I have.   

That stated, the proprietary shock tune does give the bike a relatively supportive ride character, and if you’re in the market for a shorter travel bike like this it shouldn’t disappoint. The Fuel EX has a fairly planted feeling given its light weight, and for the right rider, it is a very well thought out and executed trail partner.   

Finally, there are a few unique features on this bike that are worth a look. The storage compartment in the downtube is exactly the kind of innovation I like to see. It allows me to bring everything I need on a ride without wearing a pack, and I don’t have to strap gear against the pretty paint job. It’s considerably smaller than the downtube hatch in the Specialized Enduro that I’m currently testing but large enough for what I need. 

The Knock Block is another cool feature, keeping the bars from spinning and snapping the brake hose when I crash. However, I would like to see Trek open the steering radius considerably on future models. The current Knock Block keeps the steering tight enough that riders have to master the nose press, or get off and turn the bike around tight switchbacks.   

In conclusion, I wish that I had more time to test the Fuel EX. It seems like a sweet option for flowier trails and long adventures. Maybe we’ll get another run at it when they update the frame in a few years. 

⭐️ Find the Trek Fuel EX 9.8 at Trek Bikes.

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