Gear Review: OPEN O-1.0 Hardtail 29er

Rear view of the OPEN O-1.0 hardtail 29er, with the seatpost, saddle, handlebar, and for in view, bike is standing on a wide forest trail with ferns and pine trees lining both sides

The OPEN O-1.0 in its natural habitat

I jumped on the Cervelo bandwagon rather early in the game, buying their “Dual” aluminum tri bike in 2004.  It was by far the best value for the coin, with the best adjustability and the most confidence-inspiring geometry on the market.  Nine years later, it still works flawlessly as a tri bike and even holds its own on gravel roads and mountain passes. Last year, Gerard Vroomen, co-founder of Cervelo, announced he was branching off to start a new company along with ex BMC CEO Andy Kessler. Together they founded OPEN, with a carbon hardtail 29er as their first offering. I knew it would be something special.

Silver Cervelo Dual triathlon bike resting on a tree with orange leaves on the ground

Cervelo – the best in the business for triathlon bikes

As luck would have it, my local bike shop Freshbikes is one of a select group of retailers in the country that teamed up with OPEN to offer their goods.  I was even more fortunate to get a sweet deal from Freshbikes on the OPEN O-1.0.

OPEN 0-1.0 matte black MTB with rotor cranks, Mavic crossmax SLR 29er wheels, and a Rock Shox SID WC fork, resting on a tree in forested XC trails

XC racing machine

After testing several carbon 29ers from large bike manufactures, I was immediately blown away by the OPEN.  With the lightest production frame on the market, a “BBright” bottom bracket, super stiff Mavic wheels, and a fantastic Rotor crankset, the bike accelerates like a rocket. Full internal cable routing gives the bike a clean, stealthy look and protects the brake and shift cables from grime and debris. Perhaps the greatest aspect of the bike is its ability to absorb trail chatter. The rear brake mounting posts are positioned on the chainstay, which allows the pencil-thin seatstays to provide unbeatable vertical compliance.  Combined with the extra flex afforded by the small-diameter seatpost and damping from my 2.25 in. Schwalbe tubeless tires, the ride is as smooth as it gets without rear suspension.

Fording a creek with the OPEN on my shoulder and 30ft trees lining both sides of the creek

Fording a creek with the OPEN, hardly notice it on my shoulder

View of the front and rear shift cable and rear brake cable tucking neating into the frame at the left side junction of the headtube, toptube, and seattube

Sleek internal cable routing

View of the crankset and direct mounted front derailleur, Freshbikes decal is visible on the bottom of the downtube

Direct-mount front derailleur and the flawless Rotor cranks

View of the junction of the seatpost, seattube, and seatstays

Narrow seatpost and pencil-thin seatstays for maximum compliance

View of the rear brake post mount on the chainstay, with shimano xtr calipers and 160 mm rotors

The rear brake post mount is elegantly placed on the chainstay

Road side picture of the author, standing with the OPEN on a gravel road with the Appalachain mountains in the background

A climber’s dream!

Just as is the case with Cervelo, OPEN gets bike geometry.  After dialing in my coordinates and touch points with Freshbikes fit-guru Clovis Anderson, I feel more comfortable than ever on a mountain bike.  The OPEN’s steering is very direct, which helps to quickly negotiate tricky terrain.  Short 44 cm chainstays and a relatively steep 72 degree head tube angle help to speed through tight corners and switchbacks, giving the fast rolling 29er the playful feel of a 26 in rig.

Taken as a whole, the OPEN O-1.0 is a lean and mean racing machine, perfectly suited for XC MTB and XTERRA racing.  This season, I’ve piloted my OPEN to overall amateur victories at the XTERRA East and Mountain championships, as well as top finishes at Mid-Atlantic XTERRA and XC events.  Whether it’s flat and sandy singletrack in New Jersey, steep and rocky Pennsylvania trails, the mountains of Colorado, or fast and technical hard pack terrain, the OPEN simply rips!

Bike with transition gear including helmet, socks, bike shoes, and running shoes

My weapon of choice for XTERRA racing

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6 Responses to Gear Review: OPEN O-1.0 Hardtail 29er

  1. Hi Alex, thanks for the review. Glad you like the bike! All the best, Gerard.

  2. Oshri says:

    Glad to see you have a worthy steed! May it carry you well and speedily!

  3. Jason says:

    Meh. Looks like you need a new Tri bike instead of a mountain bike.

  4. Juan Pablo Garcia-Neveu says:

    Could not agree more… Amazing Open. Now there is two of us riding Open bikes at worlds; see u in Maui!

  5. gsterb says:

    Alex, that is a great looking bike!

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