Exotic Bicycle Designs and Engineering

[jedishrfu]

I’ve seen tall bikes here in Austin. They look awesome but I’d never try it because to me it’s an accident waiting to happen:

 

[bob012345]

The unicycle (AKA sociable monocycle) in the figure below never became popular.
View attachment 232987
It's from Bicycles and Tricycles by Archibald Sharp and originally published in 1896. The book is still in print.

Turned by coordinated leaning? Seems like the big wheel would provide a lot of angular momentum making turning harder.

 

[jedishrfu]

Turned by coordinated leaning?

I guess but these things won't be known unless you've ridden one. It may well be that it only rides in a straight line.

 

[bob012345]

I’ve seen tall bikes here in Austin. They look awesome but I’d never try it because to me it’s an accident waiting to happen:

View attachment 232997

One has to be old to get this but maybe a "floatilla" of these bikes will bring in the American Tricentennial. :)

 

[OmCheeto]

While often true, one will never know unless one tries. Rollerblades was a great example as was skateboards, the hula hoop and the Big Wheel. It just has to be at the right place and time with the right price and craze to make it happen.
...

To get REALLY rich, I think you need a perceived problem, that will encourage A LOT of people to pay money for a solution, that is worth developing.
I say "perceived", as lots of people seem to solve problems by throwing money at them, rather than doing the maths.
For instance, a VERY wealthy friend of mine told me a while back that she would pay for EVERYTHING to get my bicycle project up and running.
I did not take up her offer, as I knew, that bicycle maths/engineering, is really difficult.

Some examples:

Some university seniors:

0:00 - 1:00 Um..., pedaling around on a bicycle is kind of boring to watch
1:00 - 1:44 Yay! We see how that works!
1:44 - 1:56 Roll back? Um... no.
1:56 - 2:37 Nobody is going to buy a bike that takes almost a minute to get going again.
2:37 - 3:43 Analyzing the "engineering" problem
3:43 - 3:59 Well, it kind of worked
3:35 - 4:53 More riding around on a bicycle​

The following is a very good video, with maths and stuff, and kind of explains why I'm researching a mechanical, vs a dollar store electrical solution:

Acceleration

Battery energy used 8.08 Wh
Kinetic energy gained 3.59 Wh
efficiency of motor 44 %​

Regen

Battery energy gained 1.27 Wh
efficiency of generator 35 %​

 

[jrmichler]

Turned by coordinated leaning? Seems like the big wheel would provide a lot of angular momentum making turning harder.

There's a more fundamental problem. Checking this concept against the laws of physics, we see that the sociable monocycle gets its driving torque by moving the center of mass of the riders forward of the axle when they pedal. Notice that the center of gravity of the riders (roughly top of the hip bone) is only slightly below the axle centerline. When they step on the pedals, they will spin themselves around. If they accelerate slowly enough, they could ride on a level road, but that machine will never climb any significant hill.

Just because something made it into print, or even into a patent, does not mean that ever worked. When looking at new ideas or patents, it is always a good idea to check the concept against the laws of physics.

 

[Ketch22]

UPS is rolling out a pilot program in Seattle and select other cities around the world. Novel in that they are a bike with a trailer. Load both cruise to the area. Drop the trailer. Return transfer loads and repeat. Interesting.

 

[Javier Lopez]

I have a Speciallized carbon fiber bike and use itr every weekend at mountains.
I should make this improvement to increase the pedal arm length by increase the height of the axle to ground.
I thing as larger pedal arm, less times you should make the movement for the same distance.

 

[bob012345]

Suppose the wheels of a standard bike were reduced to skateboard size. Everything else being the same, could the gears be adjusted to make the rider use the same power for the same acceleration? Or would it actually take much more power? I'm thinking the total energy must be the same for the same final speed if the mechanical systems are equally efficient. Thanks.

 

[Javier Lopez]

My old bike had smaller wheel and I chequed that I make 10-15% better in flat tracks and much better if there are a lot of stones because stones generates a lot more losses to smaller wheels. In hard mountains with >7% up and down I checked no differences.
Asphalt is rought but less than ground tracks and stones not moves so less losses
Longer pedal arm size have closer size to our bones.

LOSSES and FRICTION exist!.
Without friction you can't be stand or take a pencil or make your car to run

 

[jedishrfu]

An article on Ars about the changing tech in bicycles over the past twenty five years.

https://arstechnica.com/gadgets/2018/11/25-years-of-two-wheeled-tech/