Open Cycle U.P. – first look at unique gravel race bike

‘Unbeaten Path’ designed for 700c and 650b wheels

Open Cycle recently released details of its second model, lightweight carbon gravel race bike. The U.P., short for ‘Unbeaten Path’, is designed with ample tyre clearance and has the ability to be configured for use with 700c as well as 650b wheels.


Related reading: Defining the gravel race bike

In order to keep the chainstay length down to a very nimble 420mm and still have room for 55mm-wide tyres and clearance for a road compact crankset, Open founder Gerard Vroomen opted to drop the drive-side chainstay below the bottom bracket. Not only does lowering the drive-side chainstay improve tyres and chainring clearance, it also allows the chainstay to be wider, and thus stiffer. 

Lowering the drive-side chainstay keeps the chainstay length to just 420mm while provide room for big tires and road compact chainrings:

Vroomen designed the U.P. to traverse everything from tarmac to singletrack. As such, the U.P. has clearance for 700c x 40mm gravel tyres. If the terrain calls for even more cushion, the rider can opt for 650b wheels shod in 2.1in (55mm) tyres.

  • 700c (29er) rim with 40mm cyclocross tyre =350mm 
  • 700c (29er) rim with 32mm cyclocross tyre =343mm 
  • 700c (29er) rim with 28mm road tyre =340mm 
  • 650b (27.5) rim with 2.1in mountain bike tyre =349mm 

All of these tyre options have an outside diameter within 10mm of each other, meaning the change to geometry and handling should be minimal.

The u.p. is designed to handle a number of different wheel and tire combinations :

The U.P. is designed for versatility 

Frame features

The U.P. is designed around current mountain bike thru-axle standards, with a 100×15 3T Luteus thru-axle fork and a Syntace X-12 142×12 thru-axle rear end.

Slender seatstays take the edge off, while the dropped drive-side chainstay provide ample clearance for 700x40mm gravel tires or 27.5×2.1in mountain tires :

Vroomen is adamant that this is a better set of standards than the smaller diameter thru-axles some companies are pushing for disc-equipped road and cyclocross.

“We honestly hope those efforts will fail, because they are monumentally stupid. Suggesting a 10mm rear and 12mm front axle as ‘optimal’ for road is just nuts. You may save a few grams (or not) but you also lose stiffness and more importantly, you lose all compatibility…” Vroomen wrote on his blog.

Likewise, Vroomen opted to use the post-mount standard for the rear brake, rather than the new flat-mount standard.

The U.P. uses the BB386 bottom bracket standard for compatibility with a wide range of 1x and 2x road and mountain bike cranksets.

The frame uses a 27.2mm diameter seatpost, and has a rather slack 72.5-degree seat tube. The relaxed position is intended to maximize seatpost compliance and negate the need to run a heavier, offset seatpost. (Complete frame geometry has yet to be announced.)

Other frame features include internal cable routing and a pair of bosses on the top tube for a small feed bag or tool kit. 

A pair of bottle bosses on the top tube allow a feed box to be bolted in place:

Top tube bosses are a common feature on time trial and triathlon bikes that also makes sense for long-haul gravel races

Pricing, weight and availability

The U.P frame with matching fork will retail for US$2,900 / €2,900.

The claimed weight for the U.P. frame is 1,150g / 2.54lb.

Open expects to begin shipping the U.P. in July.


As for colors, Open is currently letting potential customers vote for their preferred colorway in the comments section at