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 entire 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.
Disc brake mounts
One of the key differences between the U.P. and U.P.P.E.R. is the disc mount standard. The U.P. uses post-mount, whereas the U.P.P.E.R. is designed for flat-mount. We don't like how the bike industry keeps “inventing” new standards, so we always investigate if they are an improvement before we use them.
Post-mount brake calipers work very well, and the main argument for flat-mount is that it looks better (sigh) while a significant drawback is that the front brake always requires an adapter for mounting, adding weight and reducing braking efficiency.
So why did we decide to offer the U.P.P.E.R. with flatmounts? Three reasons:
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Shimano has decided to make the new DuraAce group only available for flat-mount. So to use their top group, you need a flat-mount frame or an adapter to fit post-mount brakes on a flat-mount frame. |
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SRAM does offer all its brakes in flat-mount and post-mount versions, but the flat-mount calipers are lighter. |
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We designed the U-turn, a new fork that accepts flat-mount calipers without the need for that silly adapter. So that disadvantage is eliminated for OPEN. |
In conclusion, to use the lightest possible brakes from both Shimano and SRAM, you need their flat-mount brakes. And thanks to the U-turn fork, you can make those set-ups even lighter by removing the normally required adapter. A win-win.
The disadvantage is that you cannot spec the U.P.P.E.R. with post-mount brakes, so for example the exotic combination of using XTR mountain bike brakes on the U.P. is not possible on the U.P.P.E.R.
One more way we have squeezed some weight out of the U.P.P.E.R.: while the new U-turn fork is set up for 160mm rotors up-front, the frame will accept 140mm rotors in the rear. Since it’s the front disc that is the limiting factor in braking, this combination of bigger up-front and smaller in the rear makes a lot of sense and saves 10-20 grams depending on the brand of rotor. If you really want to use 160mm discs in the rear of your U.P.P.E.R., then Shimano and SRAM flat-mount brakes also offers that option with their dedicated adapter (but as you know by now, we’re not big fans of adapters).
U-turn
For the U.P.P.E.R., we 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.
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.
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.
SafePost™ Pilot hole
Seatposts usually indicate a minimum insertion dimension. That keeps the seatPOST safe, but it’s also important that the seatTUBE is supported properly. The minimum insertion for that is indicated by the SafePost Pilot hole.
Bottom bracket
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, Campagnolo and SRAM but also smaller brands like THM, Rotor and RaceFace. 386 EVO even allows for the installation of many mountain bike cranks.
Geometry
Clearance for cross, road and mountain bike tires, a cross/road position and compatibility with cross/road & mountain bike drivetrains make the U.P. geometry the most complicated we’ve ever worked on. But we’re ecstatic about the result.
Keep in mind that the seattube is designed to be offset, so that your seatpost doesn't have to be. This saves a bit of weight. It also means that the toptube length appears a bit longer than the frame really is, yet another reason why toptube length is a bad measurement to rely on. Best to use stack and reach.
As you can see, the chainstays are quite short for a cross/gravel bike, despite the ability to fit the massive 54mm tires in. That's one of the benefits of the dropped drive-side chainstay.