This is the most versatile bike on the market. Here's why.
The Good: The stiffness and explosiveness of a road bike matched with mountain-bike tire clearance makes this the ultimate crossover machine. On the road, the Enve SES 3.4 discs are fast and super crisp. Ultegra Di2 is great and never got gummed up or slowed down with dust and mud.
The Bad: It’s heavier than many high-end road bikes and likely not burly enough for techy trails, so the application may be vague for some. The 11-28 cassette was a bit too stiff for road endeavors that tend toward the adventure realm. And most importantly, innovation ain’t cheap.
The Verdict: While much of the industry has been playing to the gravel-bike segment by simply adapting their road platforms, Open engineered the ultimate purpose-built machine. With road wheels and skinny tires it keeps up in the peloton. With 650bs and mountain tires, the Unbeaten Path (UP) has more clearance than pretty much any other gravel bike out there. This is a road bike you can ride almost anywhere—we’ve done just that, and loved it at every turn.
- Weight: 17.6 pounds with the Schwalbes
- Price: $8,400 as tested
- Components: Ultegra Di2 drivetrain, RS875 disc brakes
Only the second frame from Open, this full carbon beauty bears the imprint of company founder Gerard Vroomen (and the co-founder of Cervélo), with its lightweight refinement, aggressive angles, and ultimate tire clearance. Most “gravel” or “adventure road” bikes have been espousing the need for bigger tires, but only offering space for 38s or smaller. The UP, on the other hand, has been engineered to fit either 700c wheels with up to 40mm tires or 650b wheels with 2.1-inch treads. That makes this, quite possibly, the most versatile road bike on the market today—which is why it won Gear of the Year for 2016.
The trick is the drive-side chain stay, which is significantly dropped and flared for clearance while still keeping the measures tight (420mm). This makes the UP fast to accelerate and explosive in the sprints while still retaining all that tire space. The rest of the geometry is in line with modern cross machines, with a 71-degree head angle on our size medium that kept steering quick but not nervous. The chunky fork, again with huge space for all tires, is direct when steering but also supple on washboard and rough. The wire-thin seat stays helps with rear compliance, as does the skinny 27.2 seatpost, and the bottom bracket is lowered a bit for stability on dirt and loose. Finally, the BB386 bottom bracket is super stiff with a huge carbon shell around it, and it’s compatible with most cranks on the market.
Discs are the only option for brakes on the UP, which is totally the right call as the extra finesse and stopping power is obligatory on dirt and in the wet conditions you’re likely to encounter. Open also thankfully spec’d thru axles front and rear (15mm front, 142x12mm rear), which helps with wheel stiffness, steering accuracy, and safety. All bikes in this genre (and all road bikes, in our opinion) should move to these standards.
Detailing is excellent, too, with internal cable routing that somehow doesn’t beat around inside the frame, even on the roughest terrain, and beautifully formed plastic cable stops to keep it all in place. There are mounts for three bottle cages, and even mounts up top for the new breed of bolt-on, gas tanks feedbags. The small cutout on the seat tube, a quick indicator for whether you’ve upped the seat tube past the safe mark, is also a nice touch.
Open only sells the UP as a frame and fork set, meaning the parts we tried were simply the dealer’s choice (or perhaps whatever they had in stock). Our bike came equipped with an Ultegra Di2 drivetrain, which worked impeccably. We we’re amazed at how long you can go (three months was our longest on this bike) without charging. The only change we’d have made was a larger cassette out back, ideally 11-32, which would have helped with steep and rocky dirt-road climbs. The RS875 disc brakes were totally reliable and made chattering descents a breeze.
Cockpit duties were taken care of by 3T, with a carbon post, long (120mm) drop stem for keeping weight up front, and nicely shaped, sallow-drop alloy bars. We might have preferred carbon bars for some additional damping, but that’s entirely a personal choice, and the metal helps with price and adds durability in case of a crash.
The UP arrived with 650B Stan’s Valor carbon wheels mounted with 2.1-inch Schwalbe Thunderburts. This is a surprisingly light setup, and we liked the tread pattern, with an almost slick top patch for speed and small side knobs that really grabbed on turns and loose gravel and sand. The new Stan’s hubs, however, had an annoying flaw, with the axle free-floating inside the hub shell. The setup worked fine, but getting the axle aligned for reinstalling the wheel was a pain. Additionally, the nut to which the thru-axle threaded wasn’t fixed to the fork, so it had a tendency to pop off and roll around whenever the wheel was off. We also tried the brand new WTB 47c Horizon Plus tires, which would be our top pick for all-road setups that included dirt but no trail. The balloon profile yielded tons of cushion on even the most rutted roads, allowing us to go faster than testers on gravel bikes with 32mm and 38mm tires.
For road duties, we chose Enve’s new 700c SES 3.4 Discs and mounted Hutchinson Sector 28s tubeless. These wheels are incredibly fast and stiff, which really helped when hitting the pavement since the UP isn’t as racy as many straight road bikes.
While the UP is not a full-fledged roadie, it’s as close as we’ve seen a bike this versatile get. With the Enves and skinny tires, it tips the scales at just a hair over 17 pounds, and you could easily go lighter with top-grade components and a lighter set of hoops. But even at this weight, we took it on many a group ride and had no problem working into the rotations and even spending time off the front. Power transfer is exceptional, and holding speed on flats and rollers is no issues. The turnover when you’re out of the saddle isn’t quite as quick as dedicated climbing bikes on the steeps, but that’s a compromise you’d expect. The descending manners are rooted and confident, and the steering direct. The disc brakes, which allow you to blast in and out of corners harder, had us dropping friends on techy downhills.
But where we really loved the UP was with wide tires on mixed surfaces. It is the most fun we’ve had riding a road bike in years, probably because we no longer felt constrained by the terrain. From graded dirt roads to loose gravel and even single track with long slick rock passages, this bike excelled at it all. The UP’s light weight (17.6 pounds with the Schwalbes) and long positioning made plowing along on dirt and gravel roads far faster than you could manage on a mountain bike—one tester lopped over ten minutes off his previous best (on a race hard tail 29er) on a three-hour mixed terrain circuit outside of town. And all that speed translates into pure fun, like smashing along in a rally car. Before this bike, we never knew you could float corners so hard on a road bike.
There are tons of good gravel bikes on the market, such as the Specialized Diverge and last year’s Gear of the Year-winning GT Grade. But with their limited tire clearance, none that we have tried can compete with the Open. Salsa makes a few adventure bikes that compare well, especially the Cutthroat, but it’s much more of a mountain bike and wouldn’t keep up on the pavement. The UP’s ability to go from 25mm road tires all the way up to mountain-size rubber—and to do both extremes so well—puts this bike in a class of its own. But that versatility doesn’t come cheaply: the frame set goes for $2,900, while our complete tester (with the Stan’s wheels, not the Enves) sells for $8,400.
The UP finally fulfills the promise of mixed-surface bikes, and we hope that other manufacturers will take note of the extraordinary tire clearance and the full complement of cage mounts. It's a premium bike for those who want the finest, but we’d love to see mid- and bargain-range bikes adopt some of the Open’s attributes.
It will not suit dedicated roadies and racers, but if you have aspirations of ever riding more than asphalt, the UP should be on your list of bikes to consider. And for the truly adventurous who aren’t afraid to spend long days on dirt and even mix it up on trail, there’s simply no better bike out there.