A new bicycle reinvents the wheel

Sleeptech

Ummm - I can't quite get my head around his reasoning for developing this....
http://technology.timesonline.co.uk/tol/news/tech_and_web/article6366308.ece

He believes that people will be drawn to the bike because it requires more work to cycle and therefore will provide more exercise for the cyclist than a conventional bike.

Photos here
http://www.china.org.cn/china/photos/2009-05/07/content_17738257.htm

Can't figure out what the roller type thing is under the rear rack?

biondino

I don't think I can comment on the thing until I have a go on it as I honestly can't comprehend what the ride would feel like.

sarajoy

But...

The reporter says the bicycle doesn't bob up and down because the shapes have constant diameters...

But, they don't have a constant radius, or they'd be a circle... so it MUST bob up and down, seeing as the distance from ground to rear axle and ground to handlebars is directly connected to the radius.

Arrghh, what's the POINT?

Sleeptech

Was trying to figure out how it could work - gave up quickly as my head hurt trying to recall my maths lessons :?

White Line

This is stupid. And I have to agree with Sara - I spent five minutes trying to convince myself that what it was saying was correct, but I can't!

Also, check the gearing on that. :roll: How can you call that more effort?

biondino

Perhaps the roller above the back wheel provides resistance?

robmanic1

This guy sussed it;

"Ok, front ride height is maintained by the rollers at the top of the front wheel which are linked to the pivoted front axle, same principle at the rear, the saddle is clearly bolted to the frame.
The rollers bear the weight of the machine and rider not the axles."

I think?

CiB

The Times write-up claims that because the distance between two parallel lines on the outer edge stays the same regardless of the angle of rotation, the seat height remains constant. I don't accept that - the relevant distance is the radius of the wheel from axle to outer edge not the total distance across two opposite points, and by definition if the radius is not constant - is not perfectly circular - the cycle must move up & down in the vertical plane to accomodate these differences. And +1 on the 'whats the point' thoughts. Madness, utter madness...

sarajoy

Oh, I see...

Indeed there is something shifty happening at the axles, and it does seem that the frame is being supported by rollers on top of the wheels, rather than at the wheel axles.

Bloody odd.

It must be very odd to pedal.

owenlars

This is a link to how a wankel rotary engine works. You'll see the bike is exactly the same but in reverse.

http://www.youtube.com/watch?v=mGOKkIx2__w

robmanic1

owenlars wrote:

This is a link to how a wankel rotary engine works. You'll see the bike is exactly the same but in reverse.

(Snigger) Every schoolboy's favourite German aircraft!

owenlars

There's always one :-)

owenlars

There's always one :-)

robmanic1

....or two?

owenlars

Or in this case 2 (sorry for double post)

rolf_f

ChrisInBicester wrote:

The Times write-up claims that because the distance between two parallel lines on the outer edge stays the same regardless of the angle of rotation, the seat height remains constant. I don't accept that - the relevant distance is the radius of the wheel from axle to outer edge not the total distance across two opposite points, and by definition if the radius is not constant - is not perfectly circular - the cycle must move up & down in the vertical plane to accomodate these differences. And +1 on the 'whats the point' thoughts. Madness, utter madness...

The point with this bike is that the frame is not supported by the axle - it is supported by the top of the tyres. Therefore, as the bike moves forward, the frame remains at a constant height with the asymmetry of the wheels taken up by the axle moving up and down. If you look at the last photo in the link, it becomes clearer (the front is more complex).

I think it is fun - I wonder if he is planning an MTB

http://www.china.org.cn/china/photos/2009-05/07/content_17738257_4.htm

JonS123

http://en.wikipedia.org/wiki/Curve_of_constant_width

I think the "wheels" fall under a curve of constant width, similar to how vending machines accept 20 and 50p coins - wedge a 20p between two bits of wood and roll it down the length of them. (did this (well not designing silly bikes or how vending machines accept 20p's....)as part of my degree so there :P)

That said +1 to pointless idea, imagen trying to corner with different amounts of tyre thread in contact with the road during the bend

Bugly

daft idea. What sort of tyres are going to fit that? agree with JonS123 the cornering would be diabolic at any lean.

Just because its possible doesn't make it desirable,

CiB

A solution in search of a problem. By the sound of it it's hopelessly inefficient judging by the comment about cyclists enjoying the extra effort as [we'll] get fitter. I don't think we'll be seeing this in the shops in time for the Christmas rush.

always_tyred

I think there are some over complicated explanations.

The axles are just axles I think, nothing special there. But the distance between any two points on the circumference joined by a straight line through the axle is the same. So, the axles moves up and down, but the contract zones don't.