This frame is incredibly versatile, and further blurs the line between road and mountain bike disciplines as a class leading cyclocross bike. The 3 members of the U.P. (Unbeaten Path) range from OPEN all combine a road riding position with clearance for mountain bike tyres. Get yourself out of town on an adventure. Leave home on asphalt, then start grinding up gravel roads or carving down some flowy singletrack. Your riding position gets you there quickly and efficiently; the big tyres give you the grip and confidence you need to feel unstoppable.
Every U.P. and U.P.P.E.R. frame shares the same shape, geometry, intended use and most importantly: tyre clearance. But they differ in the layup of the carbon fibre, weight, fork, disc brake mounts, thru-axles and colour. The Classic U.P. uses post-mount disc brake mounts, whilst the New U.P. and U.P.P.E.R. use flat-mount disc brake mounts.
This frame fits 27.5” (650B) mountain bike tyres up to 2.1” wide. But you can also fit a 40mm cross tyre, or a 28mm road tyre, or anything else in-between (exact tyre sizes depend on manufacturing tolerances and rim width, so this is a guideline. Always make sure you have 6mm clearance between tyre and frame).
So you’ll hardly notice a difference in geometry swapping 700c cross/road and 650b mountain bike tyres on this frame, while 29er tyres with their significantly larger radius would make a total mess of the handling.
There is a second reason Open designed for 650b and not 29er tyres. They would require very long chainstays, while this frame now sports a very short 420mm rear end, enabling much quicker, more responsive handling. Most gravel and cross bikes have longer chainstays than that yet they can't fit anywhere near the same size of tyre.
Dropping the right chainstay away from the crowded area behind the bottom bracket let us build it wider and therefore stiffer (a huge effect; with the same amount of material, twice the width will give you eight times the stiffness!). Open felt this was the best solution to dealing with the fight for space between the chainrings, frame and tyre.
Making a frame entyrely out of 100% high modulus (stiff) carbon is not a good idea, especially when there are areas like the headtube that receive big impact loads. Stiffer carbon is more brittle, so it’s not appropriate for all parts of a frame. So we have used the stiffest carbon of any bike manufacturer in areas where we can, and used tougher, slightly more flexible grades of carbon where we need to.
For the U.P. and the U.P.P.E.R., we use different lay-ups, meaning the shapes of the plies and the ratio between the different materials is different for the two models, with the U.P.P.E.R. using an extremely complex lay-up.
Lateral stiffness in the rear triangle is required for an efficient drive train, but vertical compliance allows for better comfort. This frame features chainstays and seatstays that are exceptionally thin vertically to give you that compliance, whilst their lateral width and carbon fibre layup still ensure rock-solid propulsion. Truly the best of both worlds.
The downtube is the key for stiffness, connecting the steering centre of your frame with the drivetrain. The flat-out downtube’s characteristically flat outside faces allow us to strategically place strips of ultra-high modulus carbon far away from the centre plane. We’ve used the stiffest carbon exactly where it matters, guaranteed!
Zero-setback seat tube
With a minimalist 27.2mm diameter we maximize the flex in our seatpost & seat tube. This is especially a big plus on rough terrain. The seat tube angle is designed around the use of a straight, zero-setback seatpost rather than a regular seatpost with setback (we’ve never understood those). Zero-setback posts are lighter, saving you another 10-30 grams.
We are not a fan of external cables & hoses that collect dirt, risk getting stuck behind objects (particularly expensive with electronic shifting) and just don’t look that great. So the U.P. runs them internally.
With the proven MultiStop design, you can customize the frame for 2x10/11, 1x10/11 and Di2 shifting. Just pick the right insert. If you run a single chainring, you can also remove the front derailleur hanger to further clean up the frame.
Most thru-axle frames are heavier than quick-release frames. Extra carbon for the dropouts, heavy hangers, and the axle itself. But they are stiffer, so what do you want most? The answer for most people is “both”, and so we introduce the first frames that combine a thru-axle with a lower weight. How?
The ThruThread design uses the same threads that hold the thru-axle to lock the derailleur hanger into the frame. Simple, light, effective.
We didn’t just redesign the dropout, the entyre seatstay and chainstay design is optimized with the added stiffness of the thru-axle in mind. For the thru-axle itself, we recommend the stiffest design available, the Syntace X-12, but you are free to use a different 12mm thru-axle if you want.
We have designed a new fork that accepts flat-mount calipers without the need for an adapter. So you can get your Shimano or SRAM flat-mount caliper, remove the standard adapter it comes with, and bolt it directly onto our fork.
This saves weight and increases the stiffness of the braking system. We do this by making the fork dedicated for 160 mm brake rotors (140 mm is a bad idea anyway on this type of bike) and using the same through-bolt design that is normally reserved for the rear.
But the U-turn fork doesn't just save you weight on the flat-mount brake, it is also extremely light itself. At 375 grams, it is by far the lightest fork that fits GravelPlus tyres. And to save even more weight, it is comes with an extremely light 12mm Carbon-Ti custom axle
Toptube bag mount
For handy storage of your phone, camera, some tools or food, you can use the toptube bag mounts. It fits the standard toptube bags from for example Dark Speed Works and XLab as well as dedicated ruggedized bags from for example Revelate Designs.
The U.P. uses the 386 EVO bottom bracket standard. The wide (86mm) BB shell is perfect to attach the dropped drive-side chainstay to. Furthermore, it fits most of the cranks on the market, from Shimano and SRAM but also smaller brands like THM and Rotor. 386 EVO even allows for the installation of many mountain bike cranks. Not all versions of each crank fit though, so be sure to check with your retailer if you have questions.