Project CieoThis bean shaped human powered vehicle is being developed by a team of german engineering students, with the goal of racing 100 kmp over the course of an hour.

By using high tech aerodynamics and materials, the Project Cieo team has recently broken a world record, by achieving 83km over the course of an hour.

They’re still working hard at pushing the limits to find ways of hitting their proclaimed 100 kmph goal,   but what’s more interesting is how they’ve crammed two riders into their tandem….

Project CIEO Tandem Seating PositionYup, that looks fun.

Interested in learning more about the project? Visit the Project Cieo Website here.


  1. “Kilometers per hour” is abbreviated “km/h”.

    Thanks for the writeup, hadn’t heard about this project. Looks like they should be able to make it. The hour record is over 90 km for a single seat streamliner, a tandem like this should be able to beat it.

  2. Great that they’re innovating. That’s the kind of people that push this world forward!

    By the way, I’m just wondering if all these aero efforts are worth all the extra friction which is created in the mechanisms. Contrary to what Spesh say, aero is not everything – friction might also be an important factor and it will certainly be high in this setup.

    I also REALLY hope they use wheel covers on the inside if the chassis. Anyway, that’s the price of progress haha

  3. WG – at 100 kph, aero is EVERYTHING.

    The drag force is 4x higher than when you ride at 50 kph, and 16x higher than at 25 kph. How often do you notice mechanical friction at even 25 kph?

  4. You do realize that they use 4 chains in there, each wrapped tightly around cogs, and that there are many more cogs and bearings than in a regular bike? That actually creates huge amounts of friction compared to a regular bike.

    I’m not saying they should direct all the efforts at minimizing friction. I’m just not sure if sacrificing a little bit of aero resistance for the sake of mechanical efficiency wouldn’t be better. That’s all.

  5. @WG: What Androo said. At these speeds, aero is pretty much the only thing you care about. Drivetrain and rolling resistance is insignificant. A single chain setup on a normal bike has minimal resistance, and even if this ride has 4x that, it’s still nothing to worry about. The drivetrain drag stays the same with increasing speed, so the faster you go the less it matters, relatively speaking.

  6. Sure seems like more frontal area than necessary to house a tandem and I don’t agree you can ignore other losses when you’re trying to set records. Don’t discount that these riders have to perform for an hour either. On the plus side, the right rider may prefer the lower bunk 😉 My guess is there’s room for an air freshener.

    Where most tandems benefit from the second rider hiding in the slipstream at the expense of length, this solution grows the height and frontal area to shorten the wheelbase. Compared to other single rider efforts I’ve seen, it looks tall and uses smallish wheels. I’d like to see a study that shows they’ve made the right tradeoff there.

    No need to get worked up over the drivetrain though. That’s a cost you’re happy to pay.

  7. Jan is right, Bike Rumor:

    ETH stands for “Eidgenössische Technische Hochschule”, one of Switzerland’s best-reputed universities. There might be German students involved in the project, as the ETH is a magnet fpr smart people from around the world. But I think your lead is not correct, stating that a “team of german engineering students” is behind it. Looking at the names on the project’s website, a whole lot sound very Swiss to me.

    PS: Please don’t change the lead to a “team of Swedish engineering students”, that would be a bit too much clichée, mkey?

  8. @craigsj I don’t think anyone is ignoring losses here, it’s more that one should not do anything to optimize 1% of your losses, when it will negatively affect the other 99%.

    Interesting about shape tradeoffs. I don’t see a any way to significantly reduce height that doesn’t double the length – that has to have lots of consequences. Also this design puts the shoulders, widest part of the body, centrally so that the tail can taper off nicely. With the riders lying in line the tail must be even longer to get the same taper. I think you’re right that aero would be even better if it was lower, but then you have issues with the handling, construction and transport of a 6-7 meter long vehicle.

  9. That really is rough for the guy on the bottom. Fart jokes aside, there is still going to significant sweat dripping right into your face.

  10. I wouldn’t want to be the guy on the bottom. If anything goes wrong he’s perfectly positioned to get his skull crushed, castrated, and mangled at the same time.

  11. @Gunnstein Are you sure no one is ignoring loses here? I’ll quote you:

    “Drivetrain and rolling resistance is insignificant.”

    While I agree drivetrain losses aren’t significant, rolling resistance sure is and either way you are certainly ignoring them. That was the entire purpose of the statement.

    Aerodynamic losses dominate even at reasonable speeds for conventional bicycles but not for faired ones. Also, there’s no reason to assume that lowering the height “doubles the length” or that doing such thing has “lots of consequences”. Let’s hope the team doesn’t make the kinds of assumptions you do.

    I doubt handling, construction, and transport are the priorities here nor would there be a need to make the vehicle 6-7 meters long to reduce its frontal area. Good thing you aren’t the engineer. 😉

  12. This is an amazing and successful machine. Already the fastest tandem for the hour. Not far short of the solo record. If you want uncomfortable, try conventional TT bikes. When I raced, I found that aero improvements were worth the pain and the power loss. Still went faster hunched as tight as I could. Taught myself to brush the top tube with my knees.
    Both riders in the cieo machine have a much more comfortable position, but in work by Sam Whittingham, 200m record holder until last year, he produces more power upright, but then he used to be Canada track team. The aero diference is huge. When I first rode a streamliner round the old Eastway, it scared the hell out of me. When I did a private 10 TT in a basic streamlined machine they put me off first. About 21 mins later they were shaking the watches to see if they had gone wrong (before digital). Sturmey 3 speed, undergeared and a fabric fairing.
    I was race director for Battle Mountain twice, despite being a Brit. The shapes keep getting closer to highly laminar. The bikes have less resistance than 1 car wing mirror. There is quite a bit of convergent evolution. Most of the fast bikes use cameras and screens tosee ahead.

What do you think?