Verdict It’s difficult to see how any bike could do a better job of being both road and mountain bike simultaneously. The Open U.P. gives away very little to the dedicated machines of each terrain type, which is a formidable achievement. It’s a pity there’s no way to fit fixed mudguards: in a 700C or slick 650b road build they might come in useful, whereas the bag mounts on the top tube will surely not be useful to 99 per cent of Open U.P. riders. Regardless of these minor points, a lot of thought has gone into the Open U.P. and when those are the thoughts of an original thinker like Vroomen, it’s going to be a winner.
No mudguard eyes
Open is a Swiss-based company set up by Gerard Vroomen, co-founder of Cervélo, and Andy Kessler, former CEO of BMC who met Vroomen when he became international sales director at Cervélo.
Both men got out of big bike business and in 2012 set up the boutique Open brand, which makes just two models — the ONE+ — an XC racing mountain bike with a sub-900g frame — and the U.P.
The U.P frame is a blend of various grades of carbon-fibre.
Open uses “the highest modulus carbon where we can, and tougher grades of carbon where we must.”
For example, the flattened down tube is reinforced by strips of ultra-high modulus carbon at its outer edges.
With its tongue firmly in its cheek Open calls this TRCinTRS technology —‘the right carbon in the right spot’.
The U.P.’s super-clean look is achieved by routing all cables and hoses internally — which also literally keeps them clean.
The frame is mechanical and Di2 compatible.
The geometry is the clever bit of the U.P. Freed up by disc brakes, where caliper reach is not an issue, the U.P. can run 650b wheels with fat 2.1in mountain bike tyres as easily as it can a 700c wheel with road tyres, or up to a 700x40c cyclo-cross tyre, since the diameters of all of these rim/tyre combinations are very similar.
Open is not the first to do this — mid-century French tourers and utility bikes were the original pioneers of the 650b standard — but Open might be the first to apply it to a sporting bike rather than an adventure or touring bike.
The component world is your oyster when it comes to building the U.P.
This test bike, supplied by Velo Atelier (www.veloatelier.co.uk), has an off-road bias with its SRAM Force1 hydraulic groupset, which is based around a ‘1x’ single chainring and a wide ratio 10-42t cassette.
Force1’s clutched rear mech combined with the thick-thin chainring teeth allow the front derailleur to be removed, giving the bike an even cleaner look and works fantastically well.
Velo Atelier fitted HED Ardennes Plus SL 650b wheels with Schwalbe Racing Ralph 2.1 tubeless tyres, the biggest it can take, which make for pretty tight clearances.
This build, which includes some premium kit such as the ENVE finishing kit, comes to an estimated £6,000.
The geometry, the riding position, the stiffness of the frame and the overall light weight are that of a road bike, but on the extra volume of the 2.1in tyres it has the buzzing bounciness of a mountain bike.
On the road, the extra rolling resistance of the knobblies does not slow it down as much as you might expect.
It still averages 18mph+ for a lumpy road ride. However, it’s when you head off road that the real possibilities, um, open up.
The UK’s millions of acres of woods are criss-crossed with bridleways and singletrack that can be just a bit too technical or gloopy for a cyclo-crosser or gravel racer.
The U.P., in its fat-tyred 650b mode can take you up, down or through any of them.
It can’t do steep or technical sections at the same speed as a suspension mountain bike and the short wheelbase lacks a bit of stability on really tricky bits, but for a fully rigid frame that is easily capable of cruising with a club run on tarmac, what it can do — with just a change of tyre pressure — is very impressive indeed.
Watch: How to set the perfect tyre pressure
This is a pretty special bike designed by one of the keenest minds in cycling, so it’s never going to be bargain basement. It’s a premium product with a premium price tag.
However, If you think of the Open U.P. as three or even four bikes for the price of one you might begin to justify the cost.
As for the amount of admiring glances this machine attracts: priceless.
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Simon Smythe is Cycling Weekly's senior tech writer and has been in various roles at CW since 2003. His first job was as a sub editor following an MA in online journalism.
In his cycling career Simon has mostly focused on time trialling with a national medal, a few open wins and his club's 30-mile record in his palmares. These days he spends a bit more time testing road bikes, or on a tandem doing the school run with his younger son.
What's in the stable? There's a Colnago Master Olympic, a Hotta TT700, an ex-Castorama lo-pro that was ridden in the 1993 Tour de France, a Pinarello Montello, an Independent Fabrication Club Racer, a Mercian Classic fixed winter bike and a renovated Roberts with a modern Campag groupset.
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