Open Cycle UPPER Frameset
Details
U.P.P.E.R combines a road riding position with clearance for mountain bike tires. Get out of town on asphalt, hit the gravel roads or switch to single track. Your position gets you there fast; the big tires make you unstoppable.
Tire clearance
The U.P. fits mountain bike tires up to 2.1” wide. But you can also fit a 40mm cross tire, or a 28mm road tire, or anything else in-between (exact tire sizes depend on manufacturing tolerances and rim width, so this is a guideline. Always make sure you have 6mm clearance between tire and frame).
How do we fit such a wide range of tires without affecting the handling? Let's start with the numbers; below is the outside radius for various wheel+tire combos:
Every U.P. and U.P.P.E.R. shares the same shape, geometry, intended use and most importantly: tire clearance. But they differ in layup, weight, fork, disc brake mounts, thru-axles and colour.
The super-light U.P.P.E.R. with OPEN U-turn fork and flat-mount disc brakes
U-turn
For the U.P.P.E.R., has a 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.
Some may not like the exposed bolt heads on the front of the fork leg instead of them being hidden, but we actually like it. It’s a technically superior design, so this engineering choice should be clearly visible.
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 tires. And to save even more weight, it is comes with an extremely light 12mm Carbon-Ti custom axle
So the U.P.P.E.R. ships standard with the U-turn. Since the U.P. is a post-mount frame, it ships with a post-mount fork, the 3T Luteus II.
Tire clearance
To go anywhere, the U.P.P.E.R. fits tires up to 55mm wide. But wider tires are also taller, which affects the steering geometry. The U.P.P.E.R. is designed for cross & road tires in size 700c and mountain bike tires in 650b (which have a smaller rim than but an OUTER diameter similar to 700c cross tires).
Consistent outer diameter means consistent handling and compared to 700c/29er mountain bike tires, the 650b size allows for a shorter chainstay to keep the frame compact
Zero-setback seattube
With a minimal 27.2mm diameter we maximize the flex in our seatpost & seattube. This is especially a big plus on rough terrain. The seattube 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 (every little bit helps).
Part Numbers
| Option | MPN | Store SKU |
|---|---|---|
| Matte Black / Med | OPENUPPERXMA | OPE24876736K |