Tested: Trek Top Fuel 69er

WHAT: Trek Top Fuel 69er
WHERE: 920-478-4678; trekbikes.com
HOW MUCH: $2,640

A few years ago I saw Trek XC pro Travis Brown riding a bike with a 26-inch rear wheel and 29-inch front. It was a singlepeed, garage-built project bike. Brown was a fan of 29ers’ speed and cornering ability, but felt those qualities came at a cost. “You give up a little on the maneuverability, being able to manual onto or off of obstacles,” he said. “You retain that maneuverability with the 26-inch rear wheel.”

Brown’s project evolved into this Top Fuel 69er, a full-suspension trail bike built around the unique ride traits produced by mismatched wheels. Years of testing produced a bike with some interesting angles. For instance, the Fox F29 100RL fork has a custom offset of 51 millimeters, which Brown says alleviates the slow-steering feel of 29ers by producing fork trail (the span between the tire’s contact patch and the spot that the steer tube points to) closer to most standard 26-inch bikes. The fork is mated with a Fox Float RP23 rear shock, and the package is tied together with a quality mix of SRAM, Shimano and Bontrager parts.

So which way does the 69er lean? Is it a 29er with a smaller rear wheel, or vice versa? It clearly feels like a standard 26-incher with something extra up front. It’s an entirely different experience than riding a 29er—the oversized front wheel offers smooth entry to handling trail obstacles, but the bike doesn’t have that steamroller feel of a 29er. The 69er is made for ripping turns. It’s especially adept on fast, curvy singletrack; lean it, carve it and stay off the brakes—the 69er corners like a souped-up slot car. I found just one weakness: steep, technical climbs, where the tall front end can be a handful.

Twenty-niners are great, but I see Brown’s point. Ditching the burdensome rolling weight of an oversized rear wheel allows the 69er to be whipped around like your favorite XC bike, and you still reap the benefits of the big front hoop.

HIGHS: Big-wheel balance with less rolling weight; proven Bontrager wheels, cockpit

LOWS: Low-end Shimano LX cranks; having to haul 26- and 29-inch spare tubes