With both the Ironman World Championships and the UCI Road Time Trial World Championships looming, it seems like this it the time to debut the latest and greatest bikes to cut through the wind on those solo races against the clock. Cube bikes has partnered in development with the aero dynamics design specialists at Swiss Side to design what they hope to be the fastest triathlon bike in the world. That’s a lofty target for a new bike, and with new introductions from Diamondback, Cervélo, and BMC all in such a short amount of time, it looks like we are going to get to see these crazy superbikes go head-to-head very soon. Cube will have their go with Andy Raelert riding the new Aerium C:68 this Saturday in Kona, so we’ll have to check back in a week’s time to see which really was the fastest. Until then, slide on for a closer look…

Cube Project Kona C:68 carbon triathlon bike

Cube sought out Swiss Side to combine their 50 years of Formula 1 aero expertise with Cube’s own bike building background to develop the most aerodynamic carbon bike frames yet. The partnership started out last year, and very quickly made big changes to the Aerium that Andy Raelert rode to a second place finish in last year’s Ironman World Championships in Kona, Hawaii. That bike+ wheel combo was said to shave 10 mins off of his 180km time, and is already available to riders who want to buy and race that Aerium C:68 themselves.


Both side came away happy with the result, but decided that this year they needed to get Andy to that top spot so the bike has been completely reworked. The new prototype claims to shave even more minutes off with a new design that takes some radical changes and builds in an even more integrated solution for rider and gear.


The new bike has again been developed around Swiss Side’s own Hadron Ultimate 800+ aero wheelset, which claim to offer on of the best aero designs available to date.

The new Project Kona frameset sticks with Cube’s top C:68 carbon tech, like you will find on both their premium road and mountain bikes. Through the more careful use of high modulus fibers and specially formulated resins, Cube is able to deliver a final product that is 68% carbon fiber to 32% resin. That’s one of the highest ratios in the bike industry and lends a lighter and stiffer frame.

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Of course optimizing aerodynamics was the big draw in the bike, and coming to the new design through Computational Fluid Dynamics and then real wind tunnel time, Cube and Swiss Side have a bit of a unique looking bike. Probably the biggest change at first glance is the bikes dropped seatstays. We’ve seen a lot of companies slide the seatstays farther down the seattube to limit their frontal area, but Cube has taken them to a new low. Now they extend horizontally across to the downtube, both easing the transition of air and redefining the top of the massive bottom bracket of the bike. Out back the stays also get a little kick up at the dropouts and a thin aero profile before their almost horizontal transition, near parallel to the chainstays.


Up front there are big changes too. An integrated basebar/stem gets connected with a smooth fairing over the front of the bike’s headtube and front brake, and then down to the dramatically deeper fork legs. The deep headtube also gets reshaped with a window in between the steerer and the back edge of the headtube, presumably to smooth airflow even more across the front triangle.

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Cockpit integrate is excellent as well. From the front it is almost impossible to see the transitions from one element to the other. And the neat integration of the Pioneer power meter head unit between the narrowly-spaced extensions is as clean as we’ve even seen on a TT or tri bike.

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Dropping the seatstays makes for a different need to cut in a rear wheel fairing, now both above and below the stays.

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And at the top it still requires a slipper seat cluster. So Cube integrates a nice hidden clamp around the very thin seatpost with a Kamm-tail like shape.

Now we just have to wait for the weekend, to see who which new aero machine will get ridden to the top of the Ironman podium



  1. Jim E. on

    Do all of these new slab-sided Tri bikes come with a weather control app also? The typical Kona crosswinds are going to throw these right into the a’a’ lava.

  2. Pete on

    One would think that every big manufacturer would have jumped on the no-seattube bandwagon.by now.
    Why do they always leave room for next year? You’d think they’e trying to sell bikes or something.

  3. mike on

    I’m sorry, but this things good looking.
    I mean, a cross wind will kick it pretty badly. It is really damn nice looking. Hate that kind of weave though.
    The Cervelo and Diamond back, they are trying to be a Zipp. The Cervelo was nice, but its a Zipp knock off.

  4. mutron3k on

    Crosswinds? That’s what that little “window” is for! Break up the slab where the frame is most susceptible, high up, away from center of mass (your seat) and close to the steering. May be just enough to keep you out the lava

  5. Morgan on

    Great looking bike. I specially like the way the frame is shaped half way down to the cranks and toward the rear wheel. Just wondering if the front derailleur doesn’t present a serious non aero obstacle. Seems to me a removable air deflector would be great since everything else has been so well designed. Perhaps unnecessary, just my opinion.

  6. Matty on

    so many pros here,knowing stuff so much better than swisside aerodynamic pros…and a pro rider. i think they will call you guys soon for more info


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