Last week it was the Falco V, this week it’s the 2014 Dimond triathlon bike to bring the boom-style frame back in vogue.

Dimond Bikes started in 2008 with the idea to make a better hydration system for triathletes. Over the years, founders TJ Tollakson and Dave Morse tossed around the idea of a “super bike”, and things slowly came together. The frame design was inspired by the Zipp 2001, a bike long out of production but still very fast. Morse, who had since been working as an engineer at Zipp, gave Tollakson a 2001 frame as a wedding gift in 2010, and they started to modify and modernize it. From there, they decided to make a go of it and Morse and fellow Zipp engineer Karl Hall designed, engineered and made the first prototypes.

Time passed, credit cards were used, and ultimately it took Hall Morse moving to Ruster Sports, which makes tri bike cases & accessories, to bring the project back to life. In May 2013, they finalized this design in a new 11,000 square foot facility in Des Moines, IA, and just released their first bike…


Full wind tunnel test data will be shared on their website soon. For now, they’re claiming aerodynamic improvements of 4% to 28% reduced drag compared to the leading tri bikes thanks to the absence of superfluous things like seat tubes and stays. And truncated air foil tube shapes.

Frames are designed, engineered and made of US-sourced unidirectional carbon fiber, all in house in Iowa.

The headtube is reasonably short, providing plenty of stack and reach adjustment while letting the pros get super low. It’s built around standard stems, bars and forks, too, so those with existing equipment don’t need to worry about proprietary designs. The saddle clamp area allows for enough fore/aft adjustment to simulate 77º to 82º seat angles. The seat boom (aka top tube) is removable for easy packing.

The frames will retail for $5,950 and be available in small, medium and large.



  1. People- please stop calling these bikes Y-Foils. The Y-foil is a terrible trek vision of a beam bike. Beam bikes like these were pioneered by brands like softride and zipp. Look up softride rocket tt, classic tt or the Zipp 2001/3001 to understand this. These were performance bikes that were/are aerodynamically superior to many designs and still perform well. The Y-foil was a typical Trek ploy to cash in on the beam bike style. They were not stiff, aero, or performance in any way. Judging beam bikes based on that is like saying NIKE FREES pioneered barefoot running or that Elon Musk inspired the ironman comic which was created before he was born. In addition, beam bikes arose from the era of cycling design that preceded the bans that set this sport back, i.e. Graham Obree and old Faithful, Obree and the development of the superman position, and Boardman with the superman position lotus. That era saw outside of the box thinking that only went away because of uci incompetence. Look at one of the most researched and well designed bikes of the era the project 96 olympic bike and you will understand where the push for designs like this came from. NOT TREK COMMERCIALS

  2. The second photo shown is the ZIPP 2001. It may be their modified version but it is completely different from the bike shown at the top of the article.

  3. How can you take them seriously when they can’t even set the handlebar position correctly? The dude in the second photo looks like a fred, that bar position must offset all of the Aero advantages the frame adds.

  4. I don’t like knocking other peoples designs, but I have to say that this type of frame is fundamentally flawed, and I speak from experience. While it is a fine example of aero efficiency, it is a very poor example of power transmission efficiency. Years ago I had a Softride frame like this, and found that the lack of a seat tube resulted in significant frame twist while pedaling. Each time you turn the crank over the top of the stroke you lose this hysteresis work done in the frame, and have to twist the frame the other way before all of your effort going into the drivetrain. This was illustrated perfectly for me when I had the ‘AHA’ moment, when I followed a friend on his Softride and I noticed the side to side movement of the top of his rear wheel, with respect to the frame centerline. On a flat road this was up to 1.5 inch each way at a steady speed.

  5. My first thought was “another Softride” – but after a bit of research, this appears to be nothing like a “Softride” bike.

    @Mr C. – I doubt their is any “frame twist” and hence any loss of power in this bike. Considering the price point for the frame set alone, and the fact pro riders seem to be who they are targeting with this bike, I’m pretty sure the engineers took that into consideration. No way they would work so hard to gain an aero advantage only to lose that advantage lost in the power transfer. If schlubs like us think of stuff like that – imagine what the pro triathlete riding (and winning) with this bike thinks of… 🙂

  6. No matter what you Guys say here, I’m crazy about
    this Bike and its Design. I am going nuts to buy one
    now and ride it. I also like the Falco “V” which is based
    on the same Design and Technology as this awesome
    ” Dimond ” TT Bike. The Price is little steep but I like it
    so far and I’m Sold on it. I have to go with the ” Falco” V
    because it’s the same or similar ” Beam” engineering TT Bike
    but the $ 4K dollars to me looks more attractive!!!

What do you think?