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"GravelPlus" bike launched be Cervélo founder Gerard Vroomen's Open Cycles brand

Open Cycles, a bicycle brand started by Cervélo co-founder Gerard Vroomen, and up until now only offering a 29er mountain bike, has launched the new Unbeaten Path, a ‘GravelPlus’ bike made for cyclocross, gravel racing and adventure riding. The carbon fibre frame features disc brakes,  thru-axles and clearance for up to 55mm wide tyres and accepts mountain bike wheelsets and cranks, making for plenty of build options to suit different riding and terrain requirements.

The company describes the new bike as a “GravelPlus frame, a gravel grinder without limits.” Gravel and adventure is a burgeoning category of bikes, essentially cyclocross bikes modified to be more versatile to tackling a wider variety of terrain and with adjusted geometry to suit longer rides. They're not easy bikes to categorise, they loosely fit in the gap between cyclocross and mountain bikes, but there's no fixed design formula, each manufacturer has its own slightly different approach.

Open says the new Unbeaten Path has a fit and position closer to a road or cyclocross bike than a mountain bike, but an important distinction to other bikes is the fact the frame has been designed to readily accept mountain bike cranks and tyres, providing plenty of interesting build options, depending on what you have in mind. A bike built for gravel racing is going to be quite different to a long distance bikepacking setup, and it seems that versatility is key to the new Unbeaten Path. The clue is in name. It’s the sort of frame that, through tyre and component choice, you can tailor to your specific riding and terrain requirements.

 

Open has designed the frame to accept up to 55mm wide tyres. That means it can easily take a 33mm cyclocross or a 28mm slick road tyre, but it can also accept a 2.1in mountain bike tyre on a 650b wheel. Why a 650b wheel? Because the smaller diameter wheel produces about the same outside diameter as a 700c ‘cross tyre. A 650b wheel with a bigger tyre would give roughly the same outside measurement as a cyclocross wheelset, but you would benefit from the much larger tyre volume for more cushioning and traction.

The frame and fork are made from carbon fibre, with a blend of different modulus carbon used in key places. The down tube features a ‘flat-out’ profile, oversized with the outside faces flattened and reinforced with strategically placed strips of ultra-high modulus carbon to boost frame stiffness. There’s a 142x12 rear thru-axle and BB386 EVO bottom bracket. Frame weight is a claimed 1,150g for a size large.

See those two bolts on the top tube? They’re for fitting a bike bag, making it well geared towards any bikepacking exploits. One omission is the lack of mudguard mounts, which some UK cyclists that like the versatility to run mudguards in the winter will bemoan, but few of these cyclocross-inspired gravel bikes tend to come with them. With a bike able to run a range of tyre sizes, including mountain bike wheels, fitting full-length mudguards could be tricky to accomodate. 

To provide maximum crank, tyre and front mech clearance, the Unbeaten Path frame features asymmetric chainstays with a dramatically lower driveside chainstay. This effectively lowers the chainstay out of what is quite a crowded area, and provides stacks more clearance. Open also claims this lower position allows the tube profile to be increased for additional stiffness, and is twice the width it would be in the regular location.

With its R3, Cervelo popularised skinny seatstays, and the new Unbeaten Path features ‘wire stays’, extremely thin vertically chainstays and seatstays to provide a bit of compliance. The seat tube angle has been designed around a 27.2mm zero seatpost because it saves a bit of weight over a setback post.

Thru-axles are becoming commonplace on cyclocross and gravel bikes, and Open has developed what it likes to call ThruThread dropouts. It reckons most thru-axle frames are heavier than quick-release frames, so has developed a system that uses the same threads that hold the thru-axle to lock the derailleur hanger into the frame, which it claims saves a bit of weight. It has adopted a Syntace X-12 rear thru-axle, popular in the mountain bike world, along with a 15mm in the fork. The fork is a custom painted 3T carbon fibre model.

All the cables and brake hoses are internally routed and the MultiStop entry and exit ports allow the frame to be easily adapted for different groupsets, from 1x11 to 2x10 and electronic shifting. If running a single chainring setup the front mech hanger can be removed.

“For me personally, this is probably my favourite frame ever, because it best reflects how I most like to ride,” says Gerard Vroomen. “Asphalt is great to get you to the places where the real fun happens, and that is on gravel and dirt, away from cars and other fun-crushing obstacles. Over the past years, it's been hard to miss that many people feel this way, witnessing the emergence of gravel rides and other adventurous styles of riding.”

The Unbeaten Path will be shipping in July and cost $2900 for the frameset (no UK price at this stage) and will be available in either brown or orange, which colour they go with is up to you, they’ve cast open voting for the colour choice on the website. http://opencycle.com/UP

David has worked on the road.cc tech team since July 2012. Previously he was editor of Bikemagic.com and before that staff writer at RCUK. He's a seasoned cyclist of all disciplines, from road to mountain biking, touring to cyclo-cross, he only wishes he had time to ride them all. He's mildly competitive, though he'll never admit it, and is a frequent road racer but is too lazy to do really well. He currently resides in the Cotswolds.