Earlier this year we reported on the news that Gerard Vroomen, co-founder of premium road cycle brand Cervélo, was to move into mountain bikes with former BMC CEO Andy Kessler. Well the move became a reality today as news of their finalised product became available.

The brand is called open and their first product is the stunning O-1.0, a 29er hardtail that aims to be the most advanced on the market. They’ve clearly put all their knowledge gained designing the lightest, stiffest and most comfortable road frames in the world for events like Paris-Roubaix, into this ground breaking mountain bike frame.

The two partners in this new and exciting brand admit that while they don’t come from a mountain bike background, they’ve come at the challenge from a pure engineering perspective. “Yes, our engineering background isn’t in mountain bikes, but good engineering is good engineering (not to mention that thanks to its bigger tires, a mountain bike sees lower impacts than a Paris-Roubaix-winning frame). We think our outsider position is an advantage; we didn’t do anything “because it’s always been done that way”.

The remit for the frame was to make the lightest and strongest hardtail. “Our goal was to build an extremely light but strong hardtail, and ask ourselves ‘why shouldn’t we’ every step of the way. The result is the lightest 29er hardtail in production, the first frame with internal cable routing that protects while being easy to live with, the first mountain bike with BBright, a frame with a geometry truly developed from scratch for 29er wheels and a gazillion more features. You’ll find them all here, big and small.”

The frame is packed with features. The carbon frame uses a blend of different grade and modulus fibres, using the highest modulus (stiffest) carbon of any bike manufacturer where possible, helping to make it one of the lightest frames in the world. A Transition downtube is hugely oversized with flat sides place strips of ultra-high modulus carbon to give it massive stiffness. A Trapezium top tube is wide at the tapered head tube and narrows to the skinny seat tube and wafer thin seat stays.

Flattened wire-stay seat stays allow the frame to be stiff to lateral forces but flex a little in the vertical plane for compliance. Furthermore, the semi-flex chainstays are tall rectangular shapes to resist sideways forces but have some vertical give.

Cables and hoses are all routed internally, entering at the same point on the tapered head tube. It’s possibly the cleanest approach we’ve ever seen. Cable stops are integrated inside the frame to keep the dirt out and let the cables can run freely inside the frame. The brake hoses also run internally, to protect them and complete the clean look. A neat dropout brake bridge sees the two post mounts connected with a carbon bridge inside a triangular dropout.

The frame is future proof: it’s electric shifting ready. “For electric, Shimano has already introduced Di2 for its road groups. We expect its upcoming mountain bike groups to use the same technology and the O-1.0 frame is prepared for it. All you need is a special set of electric-ready cable stops and MultiStop.”

And why 29er? They cite good reasons for this decision, other than just following the current trend for big wheels. “A larger wheel is a little heavier, but that difference is small compared to the weight of the bike and rider combined. Until now, 29er frames were also considerably heavier than their 26-inch counterparts, but that’s history with the arrival of the O-1.0. An often-heard objection to 29er bikes is that the handling would be sluggish. That is true if you simply copy the 26-inch steering geometry (or modify it without knowing what you’re doing), but we know that if you test the O-1.0 frame, you’ll love the handling.“

It’s the first mountain bike frame to sport the new BBright bottom bracket standard (which was devleoped by Cervelo). A bigger axle makes power transfer better and the wider bottom bracket allows for wider downtubes.

Finally, open have taken a different approach to sizing. Rather than rely on top tube length, they work on reach and stack. It’ll be offered in four sizes from small through to large, with 20mm increments. “Stack and reach on the other hand directly describe the position of your headtube (and thus your handlebars) relative to your bottom bracket (cranks).

“So first you put the saddle at your preferred height & setback (relative to your cranks). You can achieve this on almost ANY frame with the right seatpost & saddle rail position. Stack & reach now describe where the frame will put your stem/handlebar combo relative to your saddle & cranks ”

As for the geometry, open have given the frame a 72 degree head angle and 72.5 seat angle and 439.42mm chainstays.

Have a good look at the photos in the gallery to see the details. More info at http://opencycle.com

Videos with Gerard