r2bike Open cycle 1 0 15 pound 29 mountain bike (1)

In a world where 10.2 lb production road bikes are a thing, super lightweight mountain bikes aren’t far behind. Just what does a mountain bike have to weigh to be considered light really light? Along with 29″ wheels came slightly heavier weight weenie builds, but at this point I think it’s safe to say that anything under 16 pounds would be considered really light. Especially if it has pedals. That makes r2bike’s Opencycle 1.0 build impressive at just 15.2 lbs/6.9kg with pedals.

To get the weight down the company enlisted the help of some fairly exotic parts – get the build after the jump…

r2bike Open cycle 1 0 15 pound 29 mountain bike (6)

r2bike Open cycle 1 0 15 pound 29 mountain bike (7) r2bike Open cycle 1 0 15 pound 29 mountain bike (4)

Starting with an Opencycle 1.0 frame, the front end of the bike was completed with a 3T Rigid Team Stealth fork. Cockpit choices include an MCFK stem, bar, seatpost and saddle, with stopping provided by Formula R1 Racing brakes and Ashima rotors. An interesting choice for the drivetrain includes a SRAM XX 2×10 system, instead of the ubiquitous 1x setups. However, that choice may be based around the Clavicula M3 crank complete with an SRM powermeter.

r2bike Open cycle 1 0 15 pound 29 mountain bike (2)

r2bike Open cycle 1 0 15 pound 29 mountain bike (3) r2bike Open cycle 1 0 15 pound 29 mountain bike (5)

To get the 29″ wheels as light as possible they were built with Tune Prince/Princess hubs laced to AX Lightness clincher rims running Schwalbe Thunder Burt Tires. The bike is shown with Bebop stainless pedals. Total weight comes in right at 6.9 kg, or 15.2 pounds.





  1. Big deal. I could get my SJ Expert carbon down to mid-15’s with a rigid Chisel fork and gravel grinder tires… No exotic parts needed.

    PS No mention of the cost of this rig

  2. @Scentofreason
    So you’re saying that all the XC racers and people that ride hardtails without a dropper post aren’t real mountain bikers?

    If so, well, I guess I should throw away all my mountain bikes and mountain bike gear. So, what’s a “cool” road bike?

  3. I’ma back flip it!! I’ma back flip itttt!

    No for real…. Put slicks on it and commute, cuz ain’t no body taking that to the mountain.

    Better yet…Cross race it

  4. Hey, a Bike without suspension and dropper seatpost is not a MTB…..? Really?
    Did you ever rode a 29″full rigid with the right geometry and the right specs?
    It’s a true MTB man, and more than 90% of the sh*t that many companies are try to sell.
    It’s even a Big Mx man, the essence of the MTB….. Driving abilities and rider skills are more important than sh..y technology. But you think what you want to think and do what you wan to do……. Fashion and trend victims… 😉

  5. Didn’t mountain biking start out in the 70’s on full rigid bicycles? Sounds like most of you can’t control a bike well enough to shred that thing through some trails. “I need FSR wah wah wah.” (deleted). I would change a few things on that bike, but over all it’s pretty sick IMO.

  6. @JC and DT
    My thoughts exactly…
    I rode the XC trails last night. Caught a group of “Brah-Boys” on the climb and dropped them and their dropper posts on the descent. Man, I love that ’99 Steel Ibis…narrow bars, arch supremes, 1.95 tires…

  7. @ WannaBesti

    I’m not as xtrem than you 😉
    I ride a full rigid, yes, but with 35mm wide rims, 2.25 29″ tires, hydraulic disc brakes, rigid fork with 20mm thru axle, singlespeed……. My tough is the following, everybody think and do what they want (in the allowed limits 😉 but personnaly I think that to ride a full rigid with the right geometry and the right setting is a lot of fun….. I like to ride full suspension braaaaap bikes to, but the “Caterham style” is the best for me.

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