Open Cycle ONE plus 29er and 275plus lightweight hardtail mountain bike

Open Cycle has updated their One uber lightweight hardtail mountain bike to accommodate 27.5+ tires. It’s still a race-ready 29er, but thanks to Boost spacing and a reworked rear end, the bike will now handle up to 27.5×3.0 rubber, or a healthy 29×2.4. And like a couple other brands, they’re already on board with the burgeoning 26+ scene, too – the size Small swaps between 27.5×2.4 or 26×3.0 to keep the dimensions better balanced for smaller riders. Check it out…

Open Cycle ONE plus 29er and 275plus lightweight hardtail mountain bike

At top, shown with 27.5×3.0 tires, and above with normal 29er race tires.

Open Cycle ONE plus 29er and 275plus lightweight hardtail mountain bike

Boost spacing in the rear makes room for stronger wheels and helps prep the BB area for wider tire clearance without changing the crank’s Q-factor. Open used their dropped driveside chainstay from the UP gravel bike to make more room for the tire without giving up chainring clearance. It’s a simple solution, and it also allows for a bigger tube cross section at the front of the chainstay, enhancing overall torsional stiffness under power.

Open Cycle ONE plus 29er and 275plus lightweight hardtail mountain bike

The front of the bike looks familiar, using a mix of high and regular modulus carbons where needed to balance strength, stiffness and ride quality. But Kessler says they made it quite a bit stiffer. They also changed the sizing a bit, down to three sizes – S/M/L. The Large got a little bigger, with longer reach. And the size small is no longer a 29er, it’s made specifically for 27.5 wheels. Fortunately, that doesn’t mean giving up the “plus” capability…it just means you’ll be using 26+ tires!

Open Cycle ONE plus 29er and 275plus lightweight hardtail mountain bike

Thin seatstays also help improve the ride by flexing a bit.

Open Cycle ONE plus 29er and 275plus lightweight hardtail mountain bike

The brake mounts still use both stays, with the front on the seatstay and the rear on the chainstay, but the rear one is molded into the stay more smoothly now than on the prior iteration.

Open Cycle ONE plus 29er and 275plus lightweight hardtail mountain bike

Open Cycles co-founder Andy Kessler says “this project started in Germany when we were going to work with AX Lightness, but then that brand (ran into financial trouble). So, we had this design ready to go, and then Boost came along. For us, it’s not really about wheel stiffness, but it let us play with wheel sizes. So we integrated it into this design and it allowed us to run it with 27.5+ tires.”

Gone is the BBright standard, switching to BB92. Kessler said it was difficult finding Boost compatible cranks to work with that standard, and customers wanted to have more options in cranksets.

Open Cycle ONE plus 29er and 275plus lightweight hardtail mountain bike

Claimed weight is 890g for a medium. They offer 1x, 2x and Di2 compatibility, and thanks to modular frame inserts, it’ll be ready for whatever other drivetrain options come along in the future. Retail is €/$3,200 for the frame, no complete bikes are being offered for now.

OpenCycle.com

13 COMMENTS

  1. Minus the hefty price tag, sweet bike/concept. I really want my next bike to be a 29er that can accept 27.5+ wheels. There are not a ton of high end carbon 27.5+ hardtail bikes out there.

  2. Thanks for making me spit my water out. A $3600+ hardtail. That’s hysterical.

    @Collin – a new carbon 29/27.5+ Trek Stache is in the works (per my LBS) and I wouldn’t be surprised if the new carbon Kona Honzo isn’t 29/27.5+. And my guess is the Big S won’t be far behind since the Fuse’s seem to be doing well.

    • I haven’t been keeping track but most of the 29 w/Boost that I’ve seen are also 27.5+. I ride for a pivot shop and 429Tr and the new LES go both ways

      I’d imagine it will be more odd where that is not the case.\

      Now what qualifies as a “+” may be debatable but that’s different discussion

      • I was pretty excited for the One+ but after seeing the cost, especially without OEM kit pricing, that idea went up in flames. Luckily the new LES, especially if you consider the bonus of singlespeedability, looks to be the phoenix rising out of the One+’s ashes.

    • The Stache isn’t a cross country bike. Its a great bike and versatile but its much more of a trail bike and almost an all-mountain hardtail.

  3. @FunkyMonkey people routinely pay $4000+ for a sub 2lb. hi mod road frameset. What’s so crazy about this? Sure, it represents the top price tier of the unsuspended MTB race frame market, but it’s certainly not outlandish.

  4. Back to 99 again? Horrible head angle and will it really clear a 2.2-2-3 xc tire in 29″

    Rather long chainstays also. Did they miss the update to new geometry?

  5. @veganpotter – fair point. I was dropping trail bike options vs. XC options as you point out. That being said, people race 27.5+?

    @pmurf – I tried the road thing two times and it’s not my thing. I’ve concluded I will never understand/appreciate that segment of cycling nor will I ever fit in which I’m cool with. But I’ll respectfully disagree – $4K for a road frame is outlandish even if they do sell. Good thing there are so many dentists in the world…

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