By Brett Ratner

While gobs of Interbike Demo Day attendees were fighting tooth-and-nail to get some seat time on the Cannondale Slate, another bike sat quietly under a small pop-up tent around the corner. While I didn't get to ride the Slate, I did get to ride this...and I feel pretty confident it was one of, if not the coolest bike at the entire show.

The bike in question is the U.P. (stands for "Unbeaten Path") by a relatively unknown bike brand called Open. While small, Open is run by two industry heavyweights (one co-founded Cervélo). At this time, they only offer two models; a hardtail mountain bike and the U.P., which they categorize as "gravel plus."

To the casual observer, the U.P. looks like any other disc brake cyclocross or gravel bike. But what makes the U.P. special is that it is designed to accommodate a very wide variety of wheels and tire sizes.

This includes standard road (700x23mm), cyclocross (700x32mm), gravel (700x40mm) and...(wait for it)...650b MOUNTAIN BIKE tires! Wait wut?

If your N+1 isn't jiving with your S-1, the Open U.P. could be your perfect whip. Here it's shown with what look to be 700x32mm slicks (background) and 650x2.25 mountain bike tires (foreground). 

Well, people are starting to catch on to the fact that the outer diameter of a 650b mountain bike tire (also known as 27.5) is virtually the same as a cyclocross tire. And with the advent of disc brakes, you don't have to worry about a rim lining up with brake pads. So, provided you design a frame with appropriate tire clearances, it opens up a whole realm of possibilities.

A 650x2.25 mountain bike tire fits, but barely. Fortunately, the frame was stiff enough that nothing ever rubbed. I'd likely go with something a touch smaller in the back, however.

Specifically, imagine being able to hop on the Wednesday night group road ride, hit your local mountain bike trail after work on Friday, explore your favorite gravel roads on Saturday, then line up for a 'cross race on Sunday...all on the SAME BIKE! Granted, you'll need multiple wheelsets to accomplish this, but hypothetically that's a lot cheaper and easier than buying and maintaining three or four different bikes.

The U.P. is available only as a frameset. But what a frameset it is. In addition to being ridiculously light and stiff, yet stable and comfortable, it's clear the designers really thought things through when designing it.

Here are some specific examples:

• Top-tube braze-on for secure mounting of your "bento box" (the place you keep your gels and Clif Bars on long rides)
• Internal cable routing, which allows for easy mounting of frame bags for gravel adventures, and shouldering of the bike should you want to race 'cross on it
• Front and rear through axles, which help ensure your disc rotors always line up when you swap wheels. Plus they're super stiff for better cornering, acceleration and climbing
• A third water bottle mount (water carrying capacity is crucial on long gravel adventures)
• Thin seat stays for better shock absorption on bumpy terrain
• A unique dropped right chain stay design, allowing for simultaneous tire and crank clearance without having to compromise handling by making the wheelbase undesirably long

The U.P. frameset offers a wealth of smart design details, demonstrating that they're really paying attention to what gravel guys are wanting in a bike.

Taking the U.P. for a spin, it was everything I hoped it would be. It felt light as a feather on the gravel and paved climb to the trail head (granted, the SRAM CX1 build and Enve carbon wheels helped). When I stomped on the pedals, it aggressively accelerated like a road bike. Shooting off onto the singletrack trails, it felt confident, quick turning and sure footed.

Operating the brakes from the hoods and sometimes the drops, my hands got tired a lot more quickly on the descents than they would on flat bars. So in addition to the lack of suspension, this isn't your ideal bike for bombing down chairlift-serviced downhill runs at Whistler (it WILL climb up them though). But other than that, I felt perfectly at home, even in rockier sections.

It was a shame Open's booth didn't see the long lines other brands enjoyed. But after seeing a fair amount of glowing, post-Interbike press about the U.P., I'd expect that change next year. I also expect more brands offering bikes in this new category. 

So my conclusion?

While I certainly had fun riding a couple of longer-travel full-suspension trail bikes at Demo Day, honestly they would just slow you down on the trails we have here in the Chicago area.

In contrast, a lot of us (myself included) periodically ride our cyclocross bikes on our local singletrack. I can't speak for everyone, but my experience has been that 'cross bikes would totally shred Midwest trails if you didn't have to carefully pick lines around roots and rocks so you don't pinch flat or damage a rim.

The Open U.P. gives you that ability to shred. And if you have any cyclocross racing or gravel riding experience, you will feel perfectly at home in the drop bar riding position. And, I feel pretty confident that you'll be able to hang just fine on road rides with the proper rubber installed.

I have to take a moment to give props to local rider Paolo from The Bonebell. Last year he, working with Humble Frameworks, welded up a custom frame that does EXACTLY what the U.P. set out to do. And since Paolo got it, I think I've seen him on another bike maybe twice. He's done everything on the bike I've described. Clearly he was on to something.

So, maybe this gravel plus category is the next big thing? I don't necessarily see it replacing trail and enduro bikes out west. But here in the Midwest, the U.P. could be the perfect, do-anything bike.

The U.P. is presently available as a frameset for $2,900 MSRP. Includes the frame, fork, seat tube collar, front thru-axle and a spare rear derailleur hanger.

Visit http://up.opencycle.com/ for more information.

About the Author
Brett Ratner (brett@thechainlink.org) began commuting by bike in 2005. Shortly thereafter, his interest in cycling expanded to century rides, bike camping and trail riding. The competition bug bit in 2012 and nowadays he races cyclocross, track, mountain bikes, criteriums and gravel for The Bonebell.