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If you look closely in the video, the front brake has never been used. There are no scuff marks on the rim, and brake pads always make scuff marks. I suspect

If you look closely in the video, the front brake has never been used. There are no scuff marks on the rim, and brake pads always make scuff marks. I suspect that if he used the front brake, it would crush the rim. This is one of the big engineering challenges for companies making rims out of carbon fiber: the compression forces from the brake pads can reach up to a thousand psi, because the brake levers provide mechanical advantage and the pads are so small. If that's not enough, the sheer forces can also cause the fibers to separate. Building bikes out of cardboard is a very cool idea, and I wish him luck, but I think what we're seeing here is a very early and probably still unsafe prototype. There are many engineering challenges to be solved still. I'd be interested in seeing a cardboard bike frame that was built from molded pieces rather than cut and glued prefab sheets. This is how modern carbon fiber bikes are constructed. I would think that a lot of that tech could cross over.

lukeholder 14y ago
thats a big assumption to make from a video. I am not engineer, but isn't there other methods for brakes other than rubber on metal?
- newman314 14y ago
  That's not an assumption. You can clearly see the brakes in the video which shows the intended use. If it's single gear, you can simply stop pedaling to brake since it would be direct drive. In fact, that would probably be the easiest as I doubt this bike is capable of any serious speed.
- AUmrysh 14y ago
  I'm sure you could use the actual drive chain (it looks like a cogged belt) to slow the vehicle down by removing energy from the rear wheel. My guess is that the front brake is only used for emergencies, and the bike works as a fixed-gear. see this about stopping a fixed-gear bike: http://howto.wired.com/wiki/Stop_a_Fixed_Gear_Bicycle http://howto.wired.com/wiki/Stop_a_Fixed_Gear_Bicycle
hammock 14y ago
It's a fixie. The front brake doesn't ever need to be used.
- pavel_lishin 14y ago
  Then why even have one?
  - schwap 14y ago
    Safety (as an emergency brake)
  - cjbprime 14y ago
    As an emergency brake, because some people don't understand that they don't know how to ride a fixie yet, and maybe also because it's illegal in many places (for example, California) to ride a bike without at least a front brake fitted.

lukeholder 14y ago

thats a big assumption to make from a video. I am not engineer, but isn't there other methods for brakes other than rubber on metal?

newman314 14y ago
That's not an assumption. You can clearly see the brakes in the video which shows the intended use. If it's single gear, you can simply stop pedaling to brake since it would be direct drive. In fact, that would probably be the easiest as I doubt this bike is capable of any serious speed.
AUmrysh 14y ago
I'm sure you could use the actual drive chain (it looks like a cogged belt) to slow the vehicle down by removing energy from the rear wheel. My guess is that the front brake is only used for emergencies, and the bike works as a fixed-gear. see this about stopping a fixed-gear bike: http://howto.wired.com/wiki/Stop_a_Fixed_Gear_Bicycle http://howto.wired.com/wiki/Stop_a_Fixed_Gear_Bicycle

hammock 14y ago

It's a fixie. The front brake doesn't ever need to be used.

pavel_lishin 14y ago
Then why even have one?
- schwap 14y ago
  Safety (as an emergency brake)
- cjbprime 14y ago
  As an emergency brake, because some people don't understand that they don't know how to ride a fixie yet, and maybe also because it's illegal in many places (for example, California) to ride a bike without at least a front brake fitted.