3 ms·

this leads me to wonder - has there been a bike design where the rear wheel is allowed to freely "steer" as well as the front wheel? sorta like a crabwalking bi

this leads me to wonder - has there been a bike design where the rear wheel is allowed to freely "steer" as well as the front wheel? sorta like a crabwalking bike able to side pedal when needed. Modern automobiles have incorporated rear wheels that turn together with the front wheel (I believe in opposite directions during a turn) in order to decrease the turning circle and improve maneuverability - I'd kill for a bike that has an electro-servo controlled rear wheel that turns to help the biker corner, etc.

khafra 16y ago
I had a bicycle like this[1] as a kid--with the rear wheel and pedals on a hinge. It wasn't significantly better at cornering--a good understanding of countersteering[2] should explain why. [1] (sorry, can't find a better reference/illustration with a cursory googleing) http://www.faqs.org/patents/app/20090014981 http://www.faqs.org/patents/app/20090014981 [2] http://en.wikipedia.org/wiki/Countersteering http://en.wikipedia.org/wiki/Countersteering (this article may not be sufficient for a thorough understanding of countersteering, but it's a good start)
bch 16y ago
See "swingbike" -- they're fun: http://blog.makezine.com/archive/2008/01/sweet_swing_bike.html http://blog.makezine.com/archive/2008/01/sweet_swing_bike.ht... In this next picture, note the seat post (not the sissy bar) is actually inserted into something like a typical headset (where a fork and stem would go on the front of a bicycle) that pivots when the pin on the underside of the frame is removed. http://www.swingbikerider.com/4-24-05%20003.jpg http://www.swingbikerider.com/4-24-05%20003.jpg
- barkingcat 16y ago
  That looks pretty cool! and insane too!
  - bch 16y ago
    Yup -- they're pretty fun... The bicycle has had nearly 200 years of evolution, though, and the reason most bicycles aren't built like this is it's simply impractical. If the fun/coolness is worth it to you though, it's worthwhile :)
RiderOfGiraffes 16y ago
The reason some vehicles have steerable rear wheels is because there are two rotational effects required when turning. One is to make the vehicle rotate, the other is to make the vehicle move in a circle. If you only steer the front wheels then when the centripetal force is correct for turning the corner, the rotational force is much larger than necessary. This leads to excessive scrubbing of the tires. Making the rear wheels steer slightly in the direction of turn the rotational force is reduced, similarly reducing the scrubbing. As a side benefit the wheels can be turned in the opposite direction at low speed, increasing the manoeuvrability.

khafra 16y ago

I had a bicycle like this[1] as a kid--with the rear wheel and pedals on a hinge. It wasn't significantly better at cornering--a good understanding of countersteering[2] should explain why. [1] (sorry, can't find a better reference/illustration with a cursory googleing) http://www.faqs.org/patents/app/20090014981 http://www.faqs.org/patents/app/20090014981 [2] http://en.wikipedia.org/wiki/Countersteering http://en.wikipedia.org/wiki/Countersteering (this article may not be sufficient for a thorough understanding of countersteering, but it's a good start)

bch 16y ago

See "swingbike" -- they're fun: http://blog.makezine.com/archive/2008/01/sweet_swing_bike.html http://blog.makezine.com/archive/2008/01/sweet_swing_bike.ht... In this next picture, note the seat post (not the sissy bar) is actually inserted into something like a typical headset (where a fork and stem would go on the front of a bicycle) that pivots when the pin on the underside of the frame is removed. http://www.swingbikerider.com/4-24-05%20003.jpg http://www.swingbikerider.com/4-24-05%20003.jpg

barkingcat 16y ago
That looks pretty cool! and insane too!
- bch 16y ago
  Yup -- they're pretty fun... The bicycle has had nearly 200 years of evolution, though, and the reason most bicycles aren't built like this is it's simply impractical. If the fun/coolness is worth it to you though, it's worthwhile :)

RiderOfGiraffes 16y ago

The reason some vehicles have steerable rear wheels is because there are two rotational effects required when turning. One is to make the vehicle rotate, the other is to make the vehicle move in a circle. If you only steer the front wheels then when the centripetal force is correct for turning the corner, the rotational force is much larger than necessary. This leads to excessive scrubbing of the tires. Making the rear wheels steer slightly in the direction of turn the rotational force is reduced, similarly reducing the scrubbing. As a side benefit the wheels can be turned in the opposite direction at low speed, increasing the manoeuvrability.