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Video Just In: Open U.P. (Unbeaten Path) frameset arrives for review

Promising versatility and gravel/adventure capability, the Open UP has a lot going for it

This orange beauty is the Open U.P. (Unbeaten Path) a gravel and adventure frameset designed by ex-Cervelo founder Gerard Vroomen and launched to much fanfare two years ago. With a certain gravel race on the horizon, we've got this frame in to see if it offers the performance, capability and versatility that we look for in a gravel and adventure road bike. On paper it certainly does, it's a bike that blurs the lines between a road and mountain bike.

Bigger tyres are a key part of a gravel bikes appeal and the Open appears to go wider than most. It'll take a 40mm tyre on a 700c rim but swap to a mountain bike 650b wheelset and you can go up to 2.1in in size. That tyre clearance provides a huge range of options to tailor the spec of the bike to match the demands of the roads and tracks you want to ride over. 

Open UP frame and fork - down tube.jpg

It's a full carbon fibre frame and this size medium (55cm) example weighs 1,150g, not exactly heavy for a reassuringly beefed up frame intended to handle some tough riding. It's feature-packed, but the most intriguing by far is the dropped drive side chainstay. It's shaped this way to provide the necessary tyre and chainset clearance whilst keeping the Q-factor narrow and the chainstays short. It's something we've seen on mountain bikes and a few other road bike brands are starting to adopt a similar approach.

Open UP frame and fork - head tube.jpg

Other details include a tapered head tube and BB386 EVO bottom bracket and full internal cable routing, compatible with any combination of mechanical or electronic gears, hydraulic brakes and 1x or 2x chainsets. The downtube has flattened sides said to improve frame stiffness while the seatstays are pencil thin which, in unison with the 27.2mm seatpost, should provide a reasonable level of comfort. 

- Open U.P. - Eurobike first ride review

Open UP frame and fork - bottom bracket.jpg

It's a disc-specific frame using the post mount standard and there are thru-axles, 142x12mm at the back and 15x100mm at the front. This is the only area where the Open UP has slightly been overtaken by the rapidly changing standards in the time since it was launched, with flat mount and 12mm front thru-axles increasingly looking likely as the de facto choice. Still, there's nothing actually wrong with post mount or 15mm thru-axles of course. As well as two regular bottle cage mounts, there’s a third on the down tube, and these top tube bolts are for fitting a bag, useful if you’re going bikepacking. 

Open UP frame and fork - stays.jpg

So that's the Open U.P. in brief, all that remains to do is get it built up. Open is a small company and only sells framesets, so you have to build it up yourself or get a good bike shop to do the job for you. We're not sure what to build it up with, there are some good examples of nice builds on the Open website and a SRAM 1x11 groupset seems a natural choice, so that might be an option. Any ideas?

- Showstopper: Podia's custom painted Open U.P. gravel bike

Open UP frame and fork.jpg

As for wheels and tyres, well we definitely want to experiment with different width tyres and really see how the bike handles and performs with everything from skinny road rubber to chunky mountain bike and gravel tyres. We're definitely going to try it on 650b wheels, I was impressed with the Panaracer Comet 650b tyres I tested briefly on the Mason Bokeh last year. It'll be interesting also to see if it can double up as a road bike with something like a 28mm tyre, and we'll of course try a 38-40mm gravel tyre on a 700c rim too.

The Open U.P. costs £2,300 and is available from

- Buyer’s guide to gravel and adventure bikes plus 16 of the best

David worked on the tech team from 2012-2020. Previously he was editor of and before that staff writer at RCUK. He's a seasoned cyclist of all disciplines, from road to mountain biking, touring to cyclo-cross, he only wishes he had time to ride them all. He's mildly competitive, though he'll never admit it, and is a frequent road racer but is too lazy to do really well. He currently resides in the Cotswolds, and you can now find him over on his own YouTube channel David Arthur - Just Ride Bikes

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