Trek Releases New Top Fuel

The Top Fuel has been a marquee model in the Trek mountain bike range for a couple of decades. Relaunched in 2015, the Top Fuel was a World Cup cross-country race weapon, piloted by the likes of Dan McConnell on the Trek Factory Racing team. In 2019 the Top Fuel had a major rethink, as Trek morphed the 100mm travel 29er XC bike into a more capable 120/115mm travel 29er platform to suit all-day adventures and the broad remit that a light

Trek have just released the fourth generation of the popular Top Fuel mountain bike. Have been reborn in 2015 as a World Cup race rig, the Top Fuel morphed into a short travel trail bike in 2019, with further refinements in 2022 until we see the latest iteration which has just been released for 2025.

Suspension on the Top Fuel 

The latest Top Fuel has a 130/120mm travel mix front to rear, but the bolstered frame can be upgraded to a 140mm fork, and a longer stroke rear shock can deliver 130mm of rear travel. Borrowing from the Trek Fuel EX, the lower shock mount allows the rider to run the standard progression or a more progressive setting to allow for better support on bigger hits or at high speed. Trek also house their MinoLink settings in this same area, with four positions available between a high and low setting, with more progression or less.

The Top Fuel has slightly better anti-squat as well, for better punch out of the saddle when accelerating into trail features or attacking a pinch climb. The same ABP rear pivot is used on the frame design.

Frame features

First and foremost, we like that Trek have kept the headset free of anything except headset bearings. Cable outer and hoses enter the frame behind the head tube, allowing for less maintenance in the long term, and more freedom of movement when packing your Top Fuel for a mountain bike trip.

The frame storage has had some small changes, but overall it is far smaller than something like the SWAT storage on Specialized’s Epic 8 EVO – another 130/120mm 29er that is made to party.

Trek have an accessory mount under the top tube, a single bottle cage placement, plenty of standover, and the ability to run the frame as a mullet (MX) configuration with a 27.5” rear wheel – if you keep the bike in the high setting.

Geometry

There are no huge changes in terms of geometry, with a 65.5 degree head angle and 76 degree seat angle. The reach on our large test bike is 477mm, and chain stays are 440mm. Ewhat is new is that Trek are offering size specific chain stays on the Top Fuel with three lengths between the small and XL frame sizes. This is a great move, as it assists in keeping the handling consistent – no matter your size.

Build kits

Trek have aluminium and carbon models of the Top Fuel, and we have the 9.8 GX Transmission model on test. With a SRAM GX Transmission group set, RockShox Pike Select+ fork and Deluxe Ultimate RCT shock, it has the major areas sorted out. Bontrager provide the Line Comp 30 wheels, Gunnison and Montrose tyres, beautiful RSL none-piece cockpit, 34.9mm dropper post and plastic dropper lever. It’s great to see Trek send their bikes out ready to be setup tubeless, with valves fitted and a bottle of sealant with the bike. It couldn’t be easier to get rolling!

Our test bike clocked in at 13.31kg before pedals were fitted.

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First ride feedback

Given the last Top Fuel I rode was the 2015 model on my Buck’s Weekend – I did not expect anything to feel the same. I thoroughly enjoyed the Specialized Epic 8 EVO I tested earlier this year, which I expected the Top Fuel to mirror on the trail. 

But I couldn’t have been more wrong.

While the Epic EVO is a souped up XC bike with burlier suspension and tackier tyres on the same frame ridden in the World Cup, the fourth generation Top Fuel goes head to head with it as a ground up short travel trail bike design. When I build the bike I was sceptical about the tyres, as they are some of the new Bontrager models that visually don’t have the heft I expected. With the silver/grey bike built up it reminded me a lot of the Norco Optic I tested in Autumn 2020. And a lot has changed since then.

On the trail, this all changed. I found the Top Fuel pedalled very efficiently for the bike type, and I only firmed up the shock on the smoothest of fire road climbs. But it was descending and moving at speed where the bike told me it was a trail bike, and not a long-travel XC bike. It feels much more balanced in rockier terrain, or on the inevitable casing of doubles which I seem to subject test bikes to. Visually, the back end looks more robust and with greater tyre clearance than something like an Epic EVO as well.

Having built the bike the night before and set it up in the carpark, I was far more impressed than I imagined I would be. I’ve got some more riding to do before completing a review, but I think Trek have made sure the Top Fuel is the perfect fit between the latest Supercaliber and the Fuel EX – and I think it may even suit those who miss the previous generation Fuel EX, by all accounts a true mountain bike.