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EB14: Open Cycle’s 15.12lb Race-Ready Hardtail Mountain Bike

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Open Cycle 1.0 ultra lightweight hardtail mountain bike

How do you take one of the lightest complete bikes and make it even lighter? Add a Lauf Fork and THM Clavicula cranks, of course.

Following frame tweaks and a production shift to Germany announced earlier this year, the chassis comes in at under 800g for a size Large. Until now, the lightest complete build we’ve seen from them was a 16.2lb bike with Di2 parts. Now, they’ve pushed more than a pound lighter by running XX1 on one of the lightest cranksets and forks on the market.

Click through for detail shots and the scale’s readout…

Open Cycle 1.0 ultra lightweight hardtail mountain bike

The tubes are primarily UD carbon for its stiffness, when woven sections placed at junctions and high stress areas to keep it strong. The Lauf leaf spring fork certainly contributed to the bulk of the weight loss while still providing some suspension.

Open Cycle 1.0 ultra lightweight hardtail mountain bike

AX Lightness makes up most of the cockpit parts and headset.

Open Cycle 1.0 ultra lightweight hardtail mountain bike

Ridges on the seat tube helped improve lateral stiffness at the BB and enabled them to switch to PFBB30 without sacrificing performance.

Open Cycle 1.0 ultra lightweight hardtail mountain bike

The Clavicula M3 isn’t THM’s lightest crankset (that would be the new Clavicula SE), but it’s the better option for mountain bikes. It’s paired with a Carbon-Ti single chainring.

Open Cycle 1.0 ultra lightweight hardtail mountain bike

Thru axle dropouts are molded in woven fibers and are ready for either electronic or mechanical systems. On earlier versions, the cable would pop out of the rounded indent just above the dropout’s cylinder, but they reworked the design to better work with XX1’s rear derailleur cable entry angle.

Open Cycle 1.0 ultra lightweight hardtail mountain bike

Open Cycle 1.0 ultra lightweight hardtail mountain bike

A Carbon-Ti thru axle bolt forgoes the lever to keep it light and clean. Magura brakes, AX lightness carbon wheels and Schwalbe tires round things out.

Open Cycle 1.0 ultra lightweight hardtail mountain bike

Complete weight without pedals is just 6.86kg (15.12lb).

OpenCycle.com

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49 Comments
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Pete
Pete
8 years ago

Doesn’t count if it doesn’t have pedals… Or a real suspension fork… Or durable multi-use dropouts.

Gabe
Gabe
8 years ago

Skipping rotor bolts and using a plastic cable end on the rear derailleur..Shame on them.

Emily
Emily
8 years ago

So this is this reason we are having problems with people sterilizing the trails. This thing will fly into a million shards the first rock or root it hits.

Peter
Peter
8 years ago

good joke…. looks like those bikes that people ride to cafe and never off-road

Mike
Mike
8 years ago

I did Leadville and Fools Gold 100 on my OPEN and have ridden Pisgah and dupont on it several times. It’s a great bike and I like the 2 person company. As for the rotor bolts, Several pro’s race only 3 bolts on the rotors. Everyone has a comment for this bike (often negative) when I am riding it (often passing them.) I’d love to purchase their new frame, the one shown here, but I have no reason to replace my current one which I love.

Gabe
Gabe
8 years ago

@Mike, I like lightweight builds, but want to see a truly “complete” bike when it comes to hardware. Running a pair of Thunder Burts would save the weight and I would rather that than skipping the rotor bolts..The plastic ferrule comment comes from being a shop mechanic and knowing how bad they suck. When I see that, I think “that’ll be bent in 15 minutes”

Paul in VA
Paul in VA
8 years ago

*snap*

Mike
Mike
8 years ago

@Gabe I guess I’m saying that it is a complete build. 3 points define a plane, the other bolts on the rotor are there as a safety precaution (I run all 6…) It’s not the complete build you would like to see but as you’ve stated, there is still weight that can be shaved.

Pete
Pete
8 years ago

This whole bike is a compromise in durability and refinement for the sake of lightweight. XTR shifts smoother and precisely than XX1. XTR brakes have better modulation and are stronger. Any conventional fork is better than that Lauf which lacks compression and rebound damping.

EBT
EBT
8 years ago

@Gabe –
You must be a pretty poverty mechanic if the plastic sealed ferrule bends on your builds. Might want to work on dialing in your housing lengths. And three bolts work just fine, even four in a 2×2 config… even on big rotors.

greg
greg
8 years ago

fork has got to go. shimano is better. three rotor bolts is not recommended for many reasons… i would have gone with the Extralite thru axle for the rear, must be lighter. and extralite hubs. at least the thing is clincher.
about the plastic housing end cap, i actually prefer them in most cases. note that the housing at that location doesnt have to move except when installing/removing the wheel. plastic doesnt corrode. i understand the preference for aluminum end caps when tight bends are required or the bend is dynamic, like at the shifter…

delquattro
delquattro
8 years ago

Mike, I too, am surprised by the narrow mindedness of fellow mountain bikers; at least the ones that comment in social media. I would expect them to be too content, as fellow mountain bikers, to leak such negativity.
Recently, electric assisted mountain bikes using trails has become a trail use topic. Mountain bikers seem to have taken the curmudgeon baton, and rode away with it. No distinction is made between a loud, smelly, powerful gas engine vs an electric motor with pedal assist; they are summarily dismissed as equally evil. Never mind that if technology continues to progress (grumbling commences?), it may become feasible to replace the chain with wires, chain rings with a generator, and the cogset with a hub motor, but not if mountain bikers are bunch of miserable Luddites. This doesn’t even take into consideration the hypocrisy on trail access.

Mike
Mike
8 years ago

the stems face place gives me the most concern.. I dont see that lasting any offroad ride.. and a faceplate failure is sure to be catastrophic on your real face…

PTymn Wolfe
PTymn Wolfe
8 years ago

I was hoping for better and funnier comments

Eric.NM
Eric.NM
8 years ago

@PTymn Wolfe:
+1
: )

Rico
Rico
8 years ago

I think it’s hot! I would ride more stock parts in my area but for a show bike it’s dope. There are some smoother XC trails out here that would be perfect for that exact setup too. And no need for a shock at all imo, give it a standard fork.

Kevinfromva
Kevinfromva
8 years ago

Cool build. I love the stuff those little nerds crank out.
@greg- get to work.

Mr. P
8 years ago

Very cool to get a mountain bike that low.

Does it come with health insurance?

P

AbelF
AbelF
8 years ago

You can use many parts of the bike as a toothpick after your post ride meal!!!!!

Chris
8 years ago

I’m really waiting to hear more about the new campy mtb group with eps. Word is they’re using a seat post mounted battery which may mean more importantly, we see a new campy seat post!

jonas l
8 years ago

Is it only me who misses Carbon-Ti carbon-steel rotors? Would save a lot. But cool build, nice with people pushing boundries.

Greg@Learnmtb.com
8 years ago

First time I’ve commented on one of these and do so only because I am amazed by the negativity! Thank you to Mike who actually owns an AX by the sounds of it for his qualified opinion, for every negative opinion-obviously this isn’t a bike you would do shuttle runs through DH rock garden trails, it’s a high end race bike you’d pull out of your quiver for smooth flowing race days. Companies like this drive creativity and push the limits that trickle down to everyone who mtb’s in the future. Look at the big picture and don’t be haters! 🙂

Nick
Nick
8 years ago

Weird build. 3 rotor bolts, but they look like steel. Why not go 6 alu, or 3 ti/3 alu. Heavy rotors too, and ESI grips aren’t light. Then they’ve stuck a daft fork on. Thunder Burts and a tuned SID would be more impressive and useable in my eyes.

Not liking plastic ferrules though…? That’s what Shimano ones are, I’d not use anything else.

Ethan
Ethan
8 years ago

Guys relax. It’s a free country.

People are allowed to build up unaffordable, light, Canadian bikes.

I just ordered three of these. But the first I plan to do when I get them is to remove one more rotor bolt

Werner
Werner
8 years ago

The fork is a joke, and who rides without pedals? Why not quote the weight without saddle, or grips or tires?

Hairy
Hairy
8 years ago

So if this is “race ready” … does anyone actually race this bike?!?!?!?

Ad
Ad
8 years ago

A lot of people are going to lose their s**t if this comments section is anything to go by when the Open full susser gets released.

7h.human
7h.human
8 years ago

I usually ride without pedals or saddle, just to save weight.

Bill
Bill
8 years ago

I like it. You know, innovation for the masses comes often from pushing the limits in one direction or the other. Carbon frames at all used to be considered plastic toys only the elite could afford, now they barely steal a glance from most people.

I do like that the focus is still “raceable”, though just how much is left to the reader to decide. You could make it a lot lighter with a rigid fork and a single speed drive train, for sure.

Ryan
Ryan
8 years ago

Should be SS.

Pynchonite
Pynchonite
8 years ago

I wish any of my bikes weighed that much. This thing just SCREAMS “Fire road racing!”

Loyd Flanders
Loyd Flanders
8 years ago

I really love this bike! The fork is boss, the rotor bolts are sweet as well as the plastic cable end caps, the best bit is its probably lighter than all the bikes of you other knobs passing judgement on a bike you’ve never ridden. You are all probably annoyed the post didn’t mention a reference to enduro! Lauf leaf forks rock and they have great styling too.

Loyd Flanders
Loyd Flanders
8 years ago

I would have Lauf forks over a pair of RS-1s

Brian
Brian
8 years ago

Yeah! “Fire road racing!”

jen
jen
8 years ago

the only question is what will hurt you first, the faceplate on the stem or the forks..

Kark
Kark
8 years ago

I googled ‘math’ and figured out how to combine the listed weight of the bike and my preferred pedals.
try it, it’s fun!

..horses for courses, and while this would in no way be suitable for my riding terrain there are places where this bike would be entirely suitable. Durable? maybe, maybe not but ffs all the negativity.. Lighten up Francis.

BMANX
BMANX
8 years ago

This is a great example of two amazing minds coming together and pushing the envelope in a good way. I like the bike and as mentioned it could still be a lot lighter if they wanted to.

I like the fork and will be looking at getting one in the near future for my 29’er build. I like what they are doing with the frame designs and can’t wait to see what their FS frame looks like.

Does a light bike build appeal to everyone, NO but I have ridden a lot of fairly light builds and they hold up with little issues.

I had a 13.5 lbs SS MTB that I used to ride all the time, did drops on and would beat up pretty good and it held up with little issues and I can assure you that OPEN is designed much better than the build I had done.

Slow Joe Crow
Slow Joe Crow
8 years ago

Building a mountain bike lighter than the 7 kg UCI road racing weight limit is an impressive exercise in weight weeniness. I still question the value of something built purely for lightness because ultimately you must a finish a race in order to win it and to me ultralight parts are asking for a mechanical. This bike goes well beyond what the top level pros do to their bikes so I question the real world performance of this bike on anything other than the smoothest, most buffed out racing trails.
Oh and @delquattro, the problem with electric bikes on the trail is not with technology, it is with the very principle of using a motor of any kind on trails explicitly labeled for non-motorized recreation. The enthusiastic response to Di2 and electronic suspension controls shows that the MTB community is perfectly OK with motors and electronics to move stuff on the bike but have serious philosophical issues with using a motor to move the bike itself.

Greg
Greg
8 years ago

And I’m afraid of spiders.

Marcel Hagener
Marcel Hagener
8 years ago

I have a carbon hard tail with a Lauf fork. Done about 14 races on it,won a few and came second too. It totally depends on what the course is like. The fork has definitely limits. Nobody would show up at downhill race with XC race bike. Mountain biking is so diverse these days. Haters on the net…can’t stand them.

theothermtbr
theothermtbr
8 years ago

If you are going to make a light bike then make a light bike. Why half a$$ this build with heavy tires, and clinchers at that. Did you grab random parts out of the warehouse to throw the bike together and expect everyone to think its impressive? Put pedals and a bottle cage on it. Is this for an adult “stryder” class? Is that just a regular chain ring without a chain guide? If so the bike isn’t even rideable. If you want to be taken seriously, make an actual lightweight rideable bike. Not something you put together with spare parts.

theothermtbr
theothermtbr
8 years ago

Sorry, I just realized it is a wide narrow chainring. I take back my chainring comment.

hellsheadbanger
hellsheadbanger
8 years ago

It is pretty amazing the way some of these commenters are able to give conclusive, long term reviews of components they have never ridden. I only wish I had telepathic powers like them.

dontcoast
dontcoast
8 years ago

…just get a CX bike!

😉

Juan Pablo
Juan Pablo
8 years ago

why would you get a cx when you can get an open for less weight and a 2.2 tire ????

Bryin
Bryin
8 years ago

I am sure some people (skinny) people get away with bike like this… but I am also sure it is not crash worthy. Since I gave up MTB riding and racing 20 years ago I don’t know much about MTB tech but I would love to ride a 15lb MTB (as long as I did not have to pay for it).

plume
plume
8 years ago

I’m making a tshirt that says – plastic ferules suck.

me
me
7 years ago

no need to skip rotor bolts, just get a set of Proti FFR Titanium bolts, is the lightest and strongest in the market. They have a Blue color that would go perfectly with this bike! They also have other kits for stem, brake calipers, bottle cages, and individual sizes as you wish.

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