The seat tube-less Baldiso One aero bike laughs in the face of UCI rules, and it's now available to buy

The unconventional Baldiso One (or B1 for short) was mostly a set of drawings when we first saw the design in late 2023, and the completed bike is now finally "a statement for cyclists who seek something extraordinary" according to its proud creators. Just 1,500 frames will be made, and the German brand claims to have delivered bikes to numerous happy customers already. 

Yes, bikes with missing seat tubes have been done before, from the cult classic Kestrel KM40 tri bike in the 90s through to the infamous Superstrata, a crowdfunded contraption that left thousands of backers around the world furious due to missing orders, substandard bike builds and a whole host of other problems; however, the 3D-printed construction method and lack of a seat tube looks to be about where the similarities between the B1 and Superstrata end. 

The brand was founded by Sebastian Baldauf, a former pro cyclist, and the B1 aero bike has been developed in collaboration with CarbonWorks, the innovative lightweight carbon specialist that has been known to make 5g bottle cages and 10g computer mounts. 

"We had the idea of a new bicycle in the beginning of 2022", Baldauf told road.cc.

"In September 2022 there was the first sketch of a frame with integrated seatpost and no seat tube. We started the 3D construction and made a first 3D-printed prototype with our little 3D printer at home in February 2023.

"Our potential customers don't take part in UCI races... our target audience for this bike are cyclists who want a special and unique road bike frame, a bike to stand out from the crowd. Similar to why people buy a car like a Lamborghini or Bentley. We have orders from Europe, but also from as far away as Costa Rica and the USA." 

CarbonWorks founder Simon Bühler suggests the finished bike ended up without a seat tube because the project began without a pre-conceived idea of what it should look like, "connecting the direct lines of forced between the basic structural elements of the frame." 

It gets even more philosophical: "The idea was to think, which lines would nature choose to connect these elements and how would a plant, maybe the branch of a tree or roots find their way to each other?" said Bühler. 

Because the bike didn't need the seat tube for structural integrity, the frame could be reinforced in other areas, hence the thicker-than-usual tubes throughout the rest of the bike. Baldiso also claims the bottom bracket area is extra stiff compared to conventional bikes, and the absence of a seat tube allows for more flex, resulting in greater comfort and smoothness on the road. 

"We are also hoping for a slightly different riding experience without the seat tube, which remains to be proven!", added Bühler. 

Baldiso claims full builds can weigh as little as 6.4kg, and its bike builder allows for almost complete customisation. Having a play with it we managed to spec ourselves a B1 with an Ultegra Di2 groupset, Ennoble carbon wheels and its standard carbon handlebar for €12,430 (around £10,458); but by upgrading to Dura-Ace and adding some Lightweight Obermayer wheels, a Darimo handlebar and CarbonWorks saddle, the bill racked up close to the €20,000 mark. 

It's safe to say that the B1 won't be for everyone, and if you like your bikes to come with seat tubes then Baldiso can cater for that too, carrying more traditional-looking aero, endurance, gravel and hardtail mountain bikes in its range. 

Still curious? Head over to the Baldiso website. 

Check out all our other bikes at bedtime here