First impressions: Trek turns Fuel into triple-threat, of sorts

Trek is refreshing its mainstay Fuel trail bike, but with a significant twist. This is not just the Fuel EX that so recently earned high praise anymore. Instead, the Fuel frame can morph from a 145mm mid-travel bike all the way to a 160mm-travel near-enduro rig that looks a lot like the last generation of Slash. It does so through a series of not-so-insignificant changes.

The goal of all this is to simplify Trek’s trail bike line by making the Fuel work for almost any rider. The adaptable frame delivers three Fuels (Fuel EX, MX and LX) with one frame. We’re testing two of these, the Fuel EX and LX. Why? To see if the full Fuel range works and if an adaptable frame design is, well, worth the cost.

Trek is not the first to use an adaptable frame design, but that is usually smaller, more boutique brands. This is not something we see often from a major brand. Neither is the new-look Project One|MTB program. That alone makes the new Fuel launch interesting, and worth a deeper look.

And, while we’re here, there’s also a matching set of electric Fuel+ bikes with some significant upgrades of their own.

Trek Fuel(s) Gen 7: EX becomes MX and LX

There are a lot of different ways to achieve simplicity, and some of them can be really complicated. In that vein, Trek’s new Fuel is three bikes, or it is one bike. Add the Fuel+ (formerly the much-lauded EXe) and it’s two bikes, or six.

The core is an adaptable frame design for the Fuel. This lets one frame convert to three(-ish) configurations, from a 29-er trail bike (Fuel EX) to a mullet wheeled Fuel MX (think Remedy, but modern) and, finally, the long-legged, 29″ Fuel LX (looks a lot like a Slash). While it can be changed between those three configurations, doing so is not easy, or inexpensive. Arguably, the new Fuel platform – and Project One|MTB program – are as much about giving riders choices up front, before they buy, as it is about a flexible frame design.

Changing between bikes requires a new suspension linkage and shock mount. Depending on what your starting Fuel is, though, and what you’re trying to turn it into, you could also need a new 27.5″ rear wheel, fork air spring, or even an entirely new fork and shock.

Why not just over-fork a Fuel EX and call it a day? Well, Trek uses the change in linkage and shock mount to change the Fuel’s rear-wheel travel, correct the geometry (to an extent) and adapt the frame’s…