Tested: Trek Top Fuel

Lighter, more versatile, easier to work on? The recent Top Fuel updates were a "greatest hits" list of changes and features that make riders happy.

As I mentioned in my writeup for that release , the new Top Fuel is meant to work well across a spectrum of riders, from the weekend XC racer to the trail rider who’s realistic about the terrain they have on hand, or those who prefer to be a little underbiked. And over the last couple of months, I’ve done my best to explore as much of that spectrum as possible for myself. The results? Excellent. I am quite enamored with this bike.

So, for all the stats, details, and changes from the old bike, check out that first look . For a real-world breakdown of the bike’s performance over a wide range of riding situations, keep reading.

Why the Top Fuel?

I have an admonition to make. Months before the Top Fuel came out, I’d resolved to get my hands on a lightweight XC bike this summer. But I had a couple of oddly specific rules. First, I wanted to be able to mullet this bike. I’m pretty convinced that my local trails are more fun on a mixed wheel bike, and I love the idea of pushing a short-travel party machine on Galbraith’s more flowy trails.

Second, it needed to be durable, and more importantly, feel durable. Last time I owned a 120 mm bike (a Transition Spur), I found myself gradually beefing it up until I caught myself riding the bike park on a short travel bike with Double Down tires and forced myself to sell it and end the madness. That bike felt a little flexy and sketchy when ridden hard. I never had an issue with it, but it was always in the back of my mind while riding it. I found myself thinking about the warranty too much.

So I wanted an mulletable XC-ish bike that wasn’t scared of meaner trails, burlier tires, and poor line choices. That’s a somewhat niche description, but the Top Fuel has met it very well.

This class of bikes represents a wide range of things to a wide range of people. Some folks are trying to build up 24 lb 120 mm bikes, while others are figuring out how to run a coil shock on the same platform. As consumers, we’re faced with a choice: go with a lighter, more XC-focused rig, or choose something burlier, more aggressive, that can handle meaner trails. For me at least, the new Top Fuel lets me have my cake and eat it too. It gives me that “better-than-an-ebike” efficiency and experience, but doesn’t feel stupid with a burlier build, pointed down gnarlier trails.

Living with the Top Fuel

Building a bike from the frame up is a great way to find all the frustrating pain points. I found none with the Top Fuel. Trek’s cable routing is really good: just push things in one end and they pop out the other. The Mino Link flip chip is handy and clever - I wish the Slash used the same one so you didn’t have to buy new brackets to swap wheel sizes. The Top Fuel has stayed creak and rattle free through the loud days of summer, and all the hardware has stayed snug. The in-frame storage is super clean and tidy, and easy to access.

The Top Fuel has routing for a mechanical derailleur, none of the cables go through the headset, and all of its standards are, well, standard, and make sense. Trek has figured out how to make bikes that don’t induce heartburn, and the Top Fuel is a great example of that. No proprietary crap, no swearing, just a tidy whip.

The builds

I’ve effectively tried out three builds of the Top Fuel at this point. First, I rode the stock XX SL 9.9 build with the nice folks from Trek on my local trails. That ride made me quite confident that I wanted to get weird with the Top Fuel’s build, and that a review from the frame up made a lot of sense.

Since then, I’ve ridden the Top Fuel frame in two main configurations, with a few core components. I unfortunately don’t have any two-piston brakes on hand so I’ve been running the Hayes Dominion A4s . They’re excellent, but also absolutely overkill on this bike. Still, I’d rather be over-braked than under. Until this week, I’ve been running my weird bastardized 10 speed drivetrain on the Top Fuel, and loving it. But the drivetrain situation in my house is in flux right now, so currently it’s got a 7 speed SRAM DH drivetrain, and will probably get GX Transmission soon. I’ve been using BikeYoke’s excellent Revive 3.0 dropper , and a 50 mm rise bar from Title components, along with the F+B bar I reviewed earlier . I’ve stuck with the stock Deluxe Ultimate shock, and have primarily been experimenting with different forks and tires.

The “Trail” version of the Top Fuel I’ve been running uses the Manitou Mattock fork, set at 140 mm, a 29” Maxxis Minion DHF up front, and a 27.5” Minion SS in the rear. The “Whippet” version uses the excellent Manitou R8 fork, with a crown spacer to get back to stock 130 mm fork geo, a Specialized Ground Control up front, and an Aspen ST out back, both 29”.

Those two setups represent a nice spectrum of possibilities for the Top Fuel, although one could widen that gap with a Sid shock for the XC rig and a coil for the trail version. I’ve experimented with the full range of progressivity and geometry adjustments with both setups. Generally, I prefer the slacker, less progressive setting for most of my riding.

Performance: Stock Build

I already touched on this in my first piece, but the stock build on the Top Fuel is excellent. Rockshox Ultimate level suspension is delightful, XX Transmission is great, and Bontrager’s wheels and tires were drama-free. Yes, I would prefer stronger brakes, but I’m also a large person who insists on riding small bikes on steep trails, so I understand that the stock Levels are “correct.” I think for most riders, a stock build of the Top Fuel will hit the mark nicely. There are no glaring weak points in the build, no frustrating tire specs, or anything like that.

In its “default” configuration the Top Fuel is the sort of bike that’s fine on the more aggressive trails I rode, and would also be fine on an XC race track. Not absurdly great, far from terrible, fine. That’s the point of the stock build: come up with a compromise that makes everyone happy and is pretty good everywhere.

Performance: Trail Build

Right out of the gate, I built the Top Fuel up as burly and aggressive as I could with parts I had on hand. I love the DHF as a more aggressive tire that still rolls fast enough. I believe more folks should run semi-slicks out back, and the 27.5” Minion SS is a longtime favorite. Throw on that 140 mm fork, put the geo chip in “high” and party on. Right out the gate I was impressed by how hard I could push the Top Fuel on familiar trails in this setup. In fact, in the first few rides I stepped up to a couple of new-to-me features, without any consideration of the bike. It felt significantly more capable than my old Spur with a similar build and about as capable as my Transition Smuggler , before I endurified it. And it went uphill really well. Snappy, responsive, quick, all the glowing adjectives.

The Top Fuel is so fun with a 27.5” rear wheel. It capitalizes on that “snap out of corners and off lips” sensation that makes short travel bikes so entertaining, and takes it to 11. It doesn’t just feel “like a dual slalom bike” but instead, makes me feel like I’m actually good at dual slalom. This is my default setup for the Top Fuel, and I could happily run this for everything, but I’m a serial experimenter, and the Top Fuel enables that, so I started experimenting.

Performance: Whippet Build

I started with that trail build, and then I bumped up to a 29” Ground Control in the rear. And then I went to a Ground Control in the front too. And then I put the Manitou R8 race fork on the front. And then, in a real fit of madness, I installed a Maxxis Aspen ST Team Issue on the rear. Holy cow, this final form is fun! At every step of that evolution I took a ride or two, to gauge how much of the bike’s descending prowess I’d lost, and how each change affected its performance. One by one, those changes weren’t that drastic, but the end result is a much lighter, faster, and more efficient bike. It’s a rocket uphill. More importantly, it’s not frustrating downhill.

No, it’s not as capable as the trail build, but I’d still ride any trail on Galbraith at speed in the bike’s current form. I’m a little more careful with where the rear tire goes - I don’t want to cut that 170 TPI Aspen ST, and my hands are a little more beat up after rough descents, but this build has been an awesome exercise in pushing a little bike outside my comfort zone.

The end result

So where does that leave me? If I owned a Top Fuel, I’d have to decide if I wanted to have one all-round build, or two builds catering to a full spectrum of riding. I think it would be entirely reasonable to have a super lightweight XC build, complete with tiny tires and suspension, along with a more “country” version with real tires, an overstroked coil shock for 130 mm in the rear, and 140 mm fork. This chassis plays nicely anywhere along that range. It’s not terrifyingly flexy or terribly heavy. In every build combination I tried, the Top Fuel was precise and confidence-inspiring. That confidence goes both directions, both in carrying the momentum to grease a tricky climbing move, or huck into chunder.

And have I mentioned that it’s available in aluminum? And it’s available in the elusive M/L size. And it has really good in-frame storage. There are lighter bikes in this travel bracket available. There are bikes with more complex suspension designs. There are bikes that can fit two water bottles in the front triangle, and there are bikes that route their cables through the headset. But, if you’re looking for one short travel bike that can cover an astoundingly wide spectrum of riding, and is really easy to live with, you’ll be hard pressed to do better than the Trek Top Fuel.