Bicycle Design

An aerodynamic concept bike

Simon L. (aka Ess) is a designer who is working on an interesting aerodynamic frame design. His blog is chronicling the development of the bike, which features openings in the head and seat tubes to allow air to pass through.

In one of his posts, Ess lists a few of the design details that help to minimize the bike’s frontal area:

1. The frame is hollow with open front and back vents.

2. Sides of the frame are parallel (made possible by placing the back cog on the outside of the frame, which suggests that you can remove the back wheel and keep the chain/sprocket in place!).

3. The headset is split into two (top and bottom).

4. Handlebar stem split into two fins

5. Integrated seat post created from two fins

6. Seat attached to the integrated seat post using a mono-fin

The design is still in the development stage, but I will continue to follow Ess’ blog to see how it progresses. It looks pretty interesting so far.

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Comments

15 responses to “An aerodynamic concept bike”

  1. Matt Avatar
    Matt

    This better be a track-only bike… looks like a good sneeze could knock you sideways!

    Reply
    1. James T Avatar
      James T

      It certainly appears to be a track bike. At first glance, it reminded me of the old Lotus track bikes with the cog outside the frame.

      Reply
  2. Will Avatar
    Will

    I wonder why he chose this layout over something like a fully-faired recumbent or something like the Lotus bikes.

    Reply
  3. Champs Avatar
    Champs

    Those are speed holes. They make the car go faster.

    It was in a Discover magazine many, many years ago, but there was a commercial introducing the world to “sky surfing” on snowboards (or similar), where the ride ended by parachute. It worked out that the drag of a flat board was better than a “swiss cheese” modification. I feel like this could happen again, except with two slippery fins having a compound effect by ramming so much air into a small central channel. Instead of being helpful, it could actually give the bike the drag profile of a single, less efficient foil.

    Reply
  4. James T Avatar
    James T

    Thanks Champs. I am certainly not an aerodynamics expert, but I also wondered about the airflow through of all of those intricate shapes that make up the frame. It seems like the intersecting airfoil shapes could create a lot of turbulence. I would like to read more about it… can you double-check your link? I would also be curios to see any research that Ess has done on the narrow twin airfoil shapes.

    Reply
  5. Billy T Avatar
    Billy T

    I’ve always wondered why designers work to reduce bike drag when the rider’s drag seems to be much greater, and it can’t be reduced much. Would a vented frame really pay off on the track?

    Reply
    1. Andrew Avatar
      Andrew

      Agreed, Billy T – the real innovation is when you incorporate features into the bike design that integrate with the rider to smooth out airflow. Certainly easier said than done, but also why Mike Burrows’ recumbent designs are so successful.

      I do think that this is an interesting concept….not sure if it makes a great deal of structural sense (seems like it would be weakest laterally and stiffest vertically, which is not really what you want…), but at least it’s worth exploring.

      Reply
    2. Ross Nicholson Avatar
      Ross Nicholson

      I concur, aerodynamic bicycles are pointless exercises if the rider is ignored.

      Reply
  6. Andy Avatar
    Andy

    A single, mostly round, tube can hold a lot of force in any direction. This design has narrow tubes, which will result in a very flexible frame unless the tube walls are much thicker, adding a lot of weight. By trying to route air through the frame, it now has to hit more pieces in more places, causing turbulent air patterns which will hurt the aerodynamics.

    Reply
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  9. Mike Avatar
    Mike

    Anyone want to take a stab at the rationale for the spoked wheels? Seems like they’d be pretty floppy with a hub flange that narrow, and I’m not sure why you wouldn’t just use a disc.

    From what I can tell this guy is a furniture designer, not sure why he’s wasting time on trying to create an aero design without incorporating some engineering knowledge or computer modeling.

    Reply
  10. Konstantin Y. Avatar
    Konstantin Y.

    morning,
    What kind of functional differences does placing the cog outside the frame produce? Why isn’t it done much right now? What impact does it have on the force distribution into the rear triangle?

    Thank You,

    Konstantin

    Reply
    1. Alex Avatar
      Alex

      I worked with the local university racing team optimizing aerodynamics for an open wheel race car and a UAV. These aren’t bikes, but I think I can say with 100% accuracy that this is a very poor aerodynamic design.

      Reply
  11. Paul Presti Avatar
    Paul Presti

    Framework for a bike with aerodynamics is necessary but what about the rider?. Unless he is paper thin………nothing is 100% dynamic

    Reply

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