Cube has taken their Ironman-targeting Aerium and given it a UCI-approved overall, ready to line-up in the start house at next month’s Tour de France. The new carbon disc brake Cube Aerium TT C:68 will cut through the air, racing against the clock under the Wanty-Groupe Gobert pro conti team.

Cube Aerium TT C:68 UCI-approved carbon time trial bike

Faced with a super aero triathlon bike that was never going to fit within the UCI guidelines, Cube’s engineers took their Aerium tri bike back to the drawing board to create a similarly aerodynamic bike for their pro riders to race at the World Tour and Grand Tour level.

The resulting Aerium TT C:68 shares many aero design and premium carbon construction characteristics with that tri bike, now with disc brakes and revised shaping to satisfy the UCI.

The biggest visual change besides more consistent disc braking, is the more standard dropped seatstay configuration and the removal of the BB fairing on the tri bike that connected those stays all the way to the downtube.

Cube reminds us that the UCI was said to have dropped the 3:1 tube shaping rule since the beginning of 2017, opening up a bit more opportunity for design flexibility. In facts, they say this is one of the first bikes to come out, after that UCI rule change. There still remain tons of cryptic rules laying out minimum & maximum tube dimensions, tube angles, and whatnot (that’s why the flattened, horizontal seatstays weren’t allowed.) If you want to dig into the details, feel free to try to decipher the UCI Technical Guidelines yourself (where you’ll also note that the 3:1 rule didn’t actually go away.)

The Aerium TT shares the Twin Head Tube design of its tri sibling, stacking a smaller tube behind the first. Under low yaw angle winds the tubes act together as one longer aero section, but as wind comes more from the side they act separately lessening side force.

By ditching rim brakes altogether, the new disc brake TT bike was able to create a cleaner front end without the need for an external fairing. Both in the fork leg and on the chainstay flat mount disc calipers were able to neatly tuck in (accompanied by 12mm thru-axles), out of the wind for a simpler solution overall, while improving rider control through the use of hydraulic brakes that can more effectively transition the tight bends needed for internal routing in the integrated aero cockpit.

Like the rest of Cube’s top end bikes the C:68 moniker denoting the 68% carbon composition to 32% resin allowed engineers to develop maximum frame stiffness for predictable handling.

Up front the bike carries over the cockpit adjustability concept developed on the tri bike. Two different integrated stem+basebar versions – high or low like this bike – give riders a wider base stack number to tune in the ideal aero fit. On top of that basebar, modular riders and extensions made by Profile give a full range of fit possibilities. Out back, the saddle clamp slides back & forth on a long rail offering huge adjustability as well.

The Aerium TT C:68 will get its official racing debut at the Tour de France Team Time Trial on July 9 in Cholet. The new TT bike will be available in three frame sizes (XS-M), plus two cockpit heights to further individual fit. Official consumer availability and pricing has not yet been released, but we will update when we know more.


    • I think they were trying to say that the biggest visual change is disc brakes, and then trying to worm in that disc brakes are more consistent.

    • The differences between a direct mount rim brake with a carbon clincher with textured brake tracks and disc are marginal. There’s a lot of disc marketing, but in the end your bike is heavier or you will have to pay more. Win-win for the bike companies but not the consumer. How many percent of roadbike riders live in the mountains and ride in the rain? For the rest it won’t really be beneficial at all.

      • Only really a win for Shimano selling more expensive disc brake components. The bike companies aren’t making more out of it. However, they are hoping to sell you a new bike because your old one is outdated.

      • This is absolutely nonsense. Disc brakes are far superior in stopping power, perform better in inclement weather and if you have ever had a gun shot blow out flying down a hill due to heat transfer, you will immediately retract your statement.

        • Absolute stopping power is the same, they are a tiny bit better in modulation. But that is important on loose grounds, not asphalt. With textured brake tracks heat is also not a big problem anymore. And never heard of disc brake fading? Or ticking noise of a hot disc brake (tolerances are very small)? The disc world is also not that perfect…

      • Well if you take California, Oregon, Washington, Utah, Colorado you are looking at more than 50% of all bicycles sales in the United States. So I am going to say quite a few live in or near the mountains. Love my rim brake bikes but I can honestly say on some of these horrible secondary roads I ride on my cross -bike with 35’s and disc they do make a huge difference. But here is an idea. YOU DON”T HAVE TO BUY ONE!! So just stop complaining.

  1. the UCI technical guidelines updates are ridiculous. Not just about 3:1 rule still showing there despite effectively having been dropped, but it still shows the disc brakes not being allowed for road bikes! When actually they are, and in their list of approved bikes there are many road disc brake bikes.

    • It does not matter if the rules makers do or do not ride bikes. The fact is that UCI much the same as NASCAR is working to create a field made up of HUMAN performance being greater than that of financial-technical-aero performance (being as the first garners the second two).

      So, are they politicians? Maybe. But, they do try to keep the playing field equal in a figurative way. As a former professional rider it is nice to know that if you are on a grass-roots team of domestiques or if you are on a larger money team, on RACE day things are closer to equal (however, budgets for training and travel are another story entirely).

      • If only that was true. The tighter the rules the more expensive it is to make any gain or distinction for your brand – you know the ones paying you wages. When these politicians can dictate your saddle position to the point I have to get permission to have my saddle in the correct position for my morphology what you are saying doesn’t quite ring true.

        • Simple solution, take away the options in geometry. Sure did make things in NASCAR more even to figure out human capabilities. Some (that little chick Danika) even had to add weight to her car. When given a template for a valid configuration all things are then equal. Your only dollars spent come into trying to get as close as possible to deviating from the rules…it is a shame that more time is spent by folks trying to buy speed than trying to achieve better performance (with out drugs). This is case in point for your stereotypical Triathlete who will spent $3000 on a wheel but will not spend an extra hour a week working on their VO2 max or doing laps in a pool.

          UCI road racing it is getting more and more clear. It is hard to “buy” speed and maintain adherence to the rules set forth.

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