CGI Concepts Rev2 Time Trial Tandem

Concept, Road Bike 9 4085

Eric Streeter, of CGI Concepts, created this virtual model of a tandem for time trial racing. One prominent feature is the “split-drive” (seen in the rendering below) which “allows for power to be applied from each rider to the left and right sides of the rear hub independently.” Interesting idea, but the left side derailleur and freehub/cassette would need to be custom too…not impossible, but a bit of a challenge.
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  1. Adam Rice December 19, 2014 at 2:46 pm -  Reply

    It’s hard to imagine this would offer much of an advantage, when riders in team time trials—not even on the same bike—seem to match pedal strokes anyhow.

  2. James Thomas December 19, 2014 at 4:52 pm -  Reply

    Yeah, I am not sold on the idea, but it is sort of interesting as a concept. On a regular tandem, the captain and stoker are oblivious pedaling the same exact cadence, so this design doesn’t change anything there. I guess the idea is to avoid the higher torque on one side of the hub from the power of two strong riders. Again though, I don’t know if that is a real issue that warrants this type of solution.

    I watched some pretty amazing athletes time trialing on tandems at the UCI Paracycling World Championships recently, and none of them were ripping spokes out of the drive side of the wheel. I would be curious to hear thoughts from someone more familiar with competitive tandem racing though.

  3. Tirapop December 20, 2014 at 11:35 am -  Reply

    Da Vinci has a clever system that puts a freewheel between each rider and the final drive.
    It allows either rider to coast and to pedal out of phase. Cadences still have to match.

    A similar system that incorporates a differential could allow different cadences.

    • James Thomas December 22, 2014 at 11:49 am -  Reply

      Very interesting. I hadn’t seen that. Thanks for the link.

  4. 54 December 22, 2014 at 2:15 am -  Reply

    An aero bar for the guy in the back? Can possibly be a comfortable thing for neither party front or back… It’ll be kind dark in there. 😀

    Look like just some student to lazy to model a tandem in CAD, and just mirror and duplicate a bike, to turn in an assignment…

    • Lauren December 22, 2014 at 9:42 am -  Reply

      You’re funny! I don’t know anything about tandems but it’s obvious you don’t know what you’re talking about — this was definitely a highly 3D modeled tandem professionally done — not just some student “mirrored and duplicated” bike design — just look at the other views. You must be young . . . without a spellchecker!

      • 54 December 22, 2014 at 4:54 pm -  Reply

        Is that why there is a quick release in the middle of the bike. for no reason what-so-ever? Pretty obvious to me, he download some bike geometry from the internet and just copy-n-paste the thing together with his brain in someone’s a$$. 😀

  5. Ted December 27, 2014 at 8:05 am -  Reply

    Have to agree with 54 here, it’s a pretty weak concept…
    No room for the Captain’s legs with the aero stokers bars, let alone the stokers head. A lot of unnecessary carbon in the mid section with 0 bb to bb support… I would not even call this a “design”… cut/paste/merge..yes
    (Ex Santana rider & builder)

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