I’ve written about my Trek Fuel EX 29er quite a bit, including a review of the amazing RS-1 fork. This morning, I got out and put some miles on the EX in an urban environment, doing some unconventional off-roading.
What it made me think about is the efficiency of the Fuel’s rear suspension.
The Fuel has the Trek Active Brake Pivot (ABP) technology, which helps prevent brake jack. That’s something that I’ve written about before, and a technology that just plain works. The Fuel also has the Dual Rate Control Valve (DRCV) technology, which I’ve also written about before, which essentially provides a two-stage shock that helps maintain a more linear shock progression throughout the full range of travel, until the very end of travel where it ramps up to soften the jar of a hard bottoming-out.
This bike also features Trek’s “Full Floater” design, which essentially means that the shock is attached to the chain stays the upper rocker arm, rather than being attached to the upper rocker arm and seat stay. If you look in this picture, you can see that the chainstay extends beyond the seatpost, and serves as the lower mount of the shock:
Accordingly, as the chainstay moves up, the bottom of the shock moves down. At the top of the shock, as the rear suspension moves up, the rocker arm pushes down on the top of the shock. This gives Trek the ability to change the leverage on the shock at different points in the travel, by carefully designing the length of the rocker arm and chainstay, as compared to a design with a fixed mounting point for the shock. The design produces 120mm of travel that feels like much more, and much less.
The DRCV allows the bike to have linear, consistent travel throughout the range, which makes the travel feel far greater–it feels bottomless. However, the full-floater design aides greatly in resisting pedal bob, and in improving efficiency. To my taste, the Fuel has less pedal bob than even the XC oriented Superfly (and I’m not alone in that opinion).
In terms of pedaling efficiency, I tend to think that the DW-link and Split Pivot designs are at the very front of the industry in producing an amazing balance between efficiency and travel. They are the mark against which I compare other designs. To my taste, the Fuel doesn’t really give up anything on efficiency as compared to those designs. Further, from my perspective, the DRCV allows the Fuel to have more consistent, more useful travel as compared to a DW or SP with a traditional shock. Accordingly, when I had to decide between this bike and a Split Pivot, I chose this bike. To be fair, I chose this bike because of the way I could spec it, as compared to the stock builds of Split Pivots…but when I made that choice, I didn’t view going with this suspension as a downside.
The combination of this rear suspension and the geometry of the Fuel makes for a very, amazingly confident bike. The front wheel is solidly out in front of you, which lends a certain feeling if invincibility. In terms of climbing, the Fuel performs solidly, and keeps traction without bucking or pedal hop–even when out of the saddle. And when an obstacle appears in the trail, the Fuel mountain-goats right over it.
In terms of rigidity, I can feel no slop in the rear end. My ENVE 29XC rims with Sapim CX-Ray spokes and DT240 hubs, coupled with the thru-axle and full-carbon rear end on the Fuel, makes this a very surgical instrument. The rear feels tight and solid in the corners, unlike some other comparable travel FS 29ers.
So, another component of the Fuel reviewed, with two thumbs up. It’s an amazing bike.