Inventor Maxwell von Stein, a recent graduate of The Cooper Union, has created a flywheel bicycle that stores forward momentum during braking to make acceleration quicker and easier when it’s time to go again.

Yes, adding a 15lb Porsche flywheel to any bike is bound to make the handling a bit off, but the concept is quite good. And it’s aimed at improving cars fuel efficiency, using our beloved bicycle as a test mule. Currently, flywheels are used in cars to maintain revs between shifts and keep the rotation of the driveshaft smooth while pistons are pounding away in an engine. They’re also partly responsible for helping slow the car when downshifting – like in this bicycle, which claims to help reduce speed by 20% when engaged during braking – by absorbing some of the rotational energy transmitted back into the system from the wheels. If Gran Turismo has taught me anything, it’s that lighter weight flywheels help the engine rev up faster, but they don’t carry the engine’s momentum as well when the foot’s off the gas, so striking the right balance between mass and weight will be one of the challenges in the progress of this design. We’d say this is a pretty great start.

Video by Science Friday, found on FastCoExist.


  1. Love the idea; but that Bridgestone was a classic! A piece of MTB history! Why couldn’t he mutilate a late model GT or some other worthless POS?

  2. I wonder how much research he’s done into the huge number of attempts to make flywheel hybrids a viable technology in cars…it’s not like the idea hasn’t been tried before. A lot.

  3. Williams f1 was going to use a flywheel hybrid system, until the FIA mandated its placement and made its use impractical. it was fully developed, and i THINK it’s starting to be used in city buses. ingenious design, that one. for cars, or bigger vehicles that start and stop a lot (subway trains?) it can work very well. for bikes, not so much.

  4. This should be tested by the postman… or would be nice to see its effects in in a downhill or bike park bike (if the tracks would include some short uphill sections, full throttle berms into a step up jump…). But how much would it influence the cornering?

  5. @Scott Weiss

    It would see that the traditional right side chain drive is between the fly wheel and the rear hub, and the chainrings have been moved to the left side of the bike to drive the rear wheel.

  6. What a good use of a bicycle that belongs to him. Hope he doesn’t disapprove of what you do with your property.

    And good to see that Craigsj is a snotty everywhere he posts.

    For a flywheel to be more practical, it needs to be smaller and lighter, spin at much higher speeds, and have an electronically-controlled clutch to preserve and reapply the generated energy. This is a school project, not a finished design.

  7. Give the guy a break. He’s designing and making his own stuff, playing with physics, gaining experience and creativity. He took on an interesting design project and it looks like it works pretty well.
    Don’t like it? When’s the last time you tried a wacky complex modification? For every good invention you gotta plough through a few off the wall ideas that may or may not work very well. So don’t make fun of engineers for this stuff, even if this specific idea has been done before.

What do you think?