PINKBIKE FIELD TEST
Trek Fuel EX 9.9 XX1 AXS
Words by Mike Levy; photography by Tom Richards
The fifty-second generation of the Fuel EX is by far the most radical, most adjustable, and probably the most capable that Trek has ever put together. It now has 140mm of travel and a 150mm fork, and you can even run a mullet wheel set-up if you use a 160mm fork. Coil-sprung shock? Not stock, but you can put one of those on as well.
There are nine 2023 Fuel EX models that start at $2,699.99 USD, but only eight of them are new bikes. That first price is for the EX 5 that's actually a carry-over using last year's aluminum frame, which means it has 130mm of travel and a 140mm fork.
Fuel EX Details
• Travel: 140mm rear, 150mm front
• 29" wheels
• 64.5° head-tube angle
• 77.2° seat-tube angle
• Reach: 485mm (lrg)
• Weight: 31.9 lb / 14.5 kg
• $10,750 USD
• More info: www.trekbikes.com
The new platform starts with the aluminum EX 7 which costs $3,700 and gets the same features as the pricier carbon bikes, including a storage compartment, adjustable geometry, and coil-compatibility. Carbon fiber shows up with EX 9.7 which costs $4,700 USD. If you have more than twice that to spend, the 9.9 XX1 AXS tested here gets all the expensive bits, including a set of carbon wheels, and will set you back $10,749 USD.
The new frame gets a much meatier-looking front-end and a more complicated design at the seat tube and bottom bracket area, but there are a few things you might recognize. Trek's ABP suspension design is one of them; those three letters are short for 'Active Braking Pivot' and describe what it's supposed to be doing. Instead of using a Horst Link or pivot on the chainstay, this system rotates concentrically around the hub axle.
Trek's also given it a 10mm bump of travel on both ends to 140mm and 150mm, making it the biggest Fuel EX ever and also the first that'll work with a coil-sprung shock. A flip-chip at the lower shock mount tweaks the leverage curve to add the progression needed to run a coil shock, or to suit rider preference.
The Mino Link pivot hardware holding the rocker and seatstays together has also been updated, but it still offers a 0.5-degree head angle and 8mm of bottom bracket height adjustment. If you want more, the biggest news is that Trek is selling different headset cups that change the angle by a full degree in either direction. The stock number is 64.5-degrees, but those who want to go slacker (or steeper) can buy a set of cups that does both. You install them one way for 63.5-degrees or the other way for 65.5-degrees. The upper cup will drop in, Trek says, but you'll need a headset press for the lower one.
The downtube storage compartment is on the new bike, and while it seems like Trek has put all the things onto the latest Fuel EX, there's one that they didn't: Knock Block. The 2023 Fuel EX has gone back to a curvy downtube with plenty of fork clearance. Climbing
There's a spectrum of good, and the previous Fuel EX was certainly somewhere in there on the climbing, but it also had active, forgiving suspension when left fully open that sure felt like it added more traction than speed. That's great if all your climbs are steep and techy, but it also leaned on its pedal-assist switch anytime they weren't. The new Fuel EX is an entirely different animal, though, with more jazz for your jam that meant the only time I firmed up suspension was on a long, boring paved climb before we hit the steep pitches leading to Whistler's Flank trails.
I would have left the suspension open had Kazimer not been half-wheeling me since we left our rental house, but I need all the help I can get at the end of the season. When I did get onto the chunky and tricky stuff, the Trek isn't as nimble as its predecessor, but it'll still get around almost anything at slow speeds if you're used to modern geometry. You can't hide the wheelbase, of course, but some foresight and body English will get you anywhere you need to go.
It's nearly as big as the Genius but manages to not feel anything like it through tight switchbacks, and our leg-o-meters were telling us that it's more efficient than both the Yeti and Norco. When you do get a brief respite between the ups, or when you can pump instead of pedal, it's also pretty good carrying speed when the ground levels out. It's obvious that the new Fuel EX is more capable than the old one, but that goes for the descents and the climbs
I've spent a lot
of time on various iterations of the Fuel EX over the last fifteen-ish years, so the mustard-colored Trek was the bike I was most interested in riding. Like all the other long-lived names, it's changed and evolved so much over that time, but this is like when you go back to school a foot taller and a lot hairier after the summer break. All of a sudden, it's a much bigger world and you have a hell of a lot more freedom to have fun and inevitably get yourself into trouble.
So much is different, but let's start with the new bike's suspension. Instead of an oddball shock, there's a normal Float X with what feels like an ideal tune; it's plenty active and fluttery when you need traction, but manages to balance that with much more support than the previous bike provided. This means that it doesn't feel like you're sacrificing one for the other, and it also means the Fuel EX is much more fun than the old bike when the trail was smooth and more level than down. Yup, despite it having more travel on both ends and being a much longer, slacker bike, it's much easier to pump and carry speed on the new Trek, a notable trait for a bike meant to be ridden everywhere and anywhere.
If my local trails were elevation-challenged or Sea Otter smooth but I still wanted a capable trail bike, I'd be choosing the Fuel EX out of our five test rigs. That sort of impression used to mean the same bike could feel a bit nervous and on-edge at the other end of the trail spectrum. Not. So. Much.
Whistler has some challenging terrain both in and out of the bike park, and there's a decent chance that the 50-year-old lady who bagged your groceries, that quiet kid sitting by himself, or the guy in a button-up shirt and no gloves are all riding some seriously scary shit on their trail bikes. The level is high, but the Fuel EX didn't have a problem with any of that kind of riding. Both the Trek and the Genius ST had the most poise when the trails were rough and fast, and the Fuel was remarkably stable and attached to the ground despite endless rocks and dust. It was also the quickest during Kazimer's timed downhill testing, further driving the point home. Again, credit to the bike's rear suspension that offered great control over the second part of the travel, never asking for more progression but also feeling like it was using the shock stroke wisely.
You can relax the front-end out to 63.5-degrees if you want to, but I spent my time on the Fuel EX set to the stock 64.5 number and didn't find the need to push that front wheel out any further. The stock handling seemed to suit my sometimes-loose riding style well, and the Fuel had a bit more composure on the steep tricky stuff than the Hightower, although I don't think I got around a single corner on the Trek as well as I did a few hundred on the Santa Cruz. But the Trek had the edge when smashing through a mess of roots and rocks, not feeling like it was moving around as much under me as the other bikes, and I just seemed to usually be in control for longer on the Fuel EX.
In the slow stuff, it had the upper hand on the Genius but seemed on par with the Yeti, Santa Cruz, and Norco in that it didn't exactly feel agile but I managed to not fall over too many times on any of them.
Getting into the details, there are a couple of picky complaints and a couple of things to like, mainly the wide range of adjustability. If the Fuel EX's suspension was still the same as the previous version, making it coil-compatible or giving it such an adjustable head angle might have made for a bike that only felt half-ready for fun. But with suspension that manages to feel both efficient enough for any sort of pedal-mission you'd have in mind while also being ready for some seriously rough terrain, it makes sense to be able to steepen or relax the handling depending on where this bike is going to end up in the world.
In the less-good column is Bontrager's one-piece carbon handlebar and stem that even comes with titanium clamping bolts. Personally, I like how clean the cockpit looks because of it, but Kazimer and I both noticed sore hands and shoulders that we didn't get when riding the other bikes. That could be down to the handlebar's stiffness, something Kazimer also noted went with a different bar on another Fuel EX he's spending time on. Other quibbles include paint that sure chipped easily and, if I had just spent this much money, I would not want to see the downtube protector sagging away from the frame. Small detail but unsightly to me.