Open is known for their strong and lightweight frames. The UPPER takes that to an entirely new level as one of the lightest gravel bikes on the market. When compared to the ever-popular OPEN U.P., this bike has the same geometry, same ride qualities, but is lighter. OPEN also built their own fork, the Open U-Turn. The build includes a complex carbon-fiber lay-up with more expensive carbon plies. Overall, the bike fits the same, rides the same, but is trimmed of the precious little fat that Open had left on the table.
Flat mount disc brakes are used which allows for lighter calipers to be fixed to the frame, but they’re only lighter if the adapters that are usually necessary with flat mount brakes are removed. Open designed their mounts so adapters are unnecessary. The result is an even lighter build and no choice in rotor sizing. It’s 160mm in front, 140mm in back, unless you want to add those adapters back on. A side effect is the bolts go through the fork and frame.
Open gravel bikes are made to be a single bike that can race and ride on road and off or handle cyclocross in style. It has the manners to feel comfortable at high and low and handle both straight lines and tight turns with aplomb. The gearing is more flexible than tire choices. You can run a single or double ring, with electronic, mechanical, or hydraulic shifting. The inner ring max is 36t, the outer ring max is 50t. When you’re running single chainrings, you can go up to a 46t single if it’s an offset style like SRAM’s, or a 50t if you’re using a flat style ring.
Designer, Gerard Vroomen wanted the seat angle to be 73-degrees for a simple reason. It creates a lighter system because you can use a zero-setback seatpost. A lighter weight of the overall system is created with zero effect on performance. To ensure the proper length throughout the frame, there is a pilot hole in the seat tube. The shaping is almost square at the bottom, and it tapers to a round 27.2mm size at the top which is better for a light, compliant, round post.
The post is at the top of the seat stays which themselves are super-thin and flattened for vertical flex and torsional stiffness. The chainstays have a similar build and the downtube has been designed for torsional stiffness. High-modulus carbon on the sides, and lower-modulus can be found in the middle. Likewise, the top and downtubes are as widely-spaced as possible to improve torsional strength for the fork. This is why the top of the headset is flush with the top tube. Internally, The U.P. runs a tapered 1 1/8” to 1 1/2” steerer, also for rigidity. The fork is also set up for wide tires, same widths as the rear end, includes a superlight 12mm thru-axle from Carbon-Ti that tightens via a 5mm hex head key.
The Open UPPER is one of the very best gravel bikes on the market. From off-raod riding to dirt roads and tarmac, the UPPER will make you feel at home. It is equipped with an electronic SRAM Red eTap AXS 12-speed system which is one of the most dominant groups available. This offers seamless shifting and intuitive gear changes in your natural riding position. All things considered, the Open UPPER is a world-class bike that can do it all.
FRAME SPECIFICATIONS
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