Bicycle Mechanics - Spokeless Wheel

Cross Posted in General Cycling Discussion
sorry if this is old news but I thought some people might be interested
http://www.reddit.com/r/technology/comments/b2g91/spokeless_bicycle/

If spokes are the problem...

There's more weight in the last half of the bike because of all of the rim support. You can feel this most when you're turning.

If it's noticeably heavier, where is the advantage?

If it's noticeably heavier, where is the advantage?

I doubt its at all an advantage Purly put this up as an item of curiousity, not a leap forward by any means, just intresting

That's some pretty nice work for what's essentially a proof of concept. Much more thought paid to aesthetics than is usual for a prototype like that. I like how they figured out how to drive the rim by adhering a belt to the inside of the it. Very cool.

Cross Posted in General Cycling Discussion
sorry if this is old news but I thought some people might be interested
http://www.reddit.com/r/technology/comments/b2g91/spokeless_bicycle/

Great.
Now the squirrels can go though your wheel w/o problems!:thumb:

So repairing a flat looks to be quite a task.

Reading some of the comments, I can see where they were coming from. Why did they do it? Because it was novel. Maybe not perfect, but this is how you find stuff out. There may be side technologies (like that drive system) that might actually be the marketable invention.

Interesting but not novel. There have been several motorcycle wheels designed in a similar spokeless (aka "hubless") configuation but they have always remained novelties and never had any demonstrable advantage.

What I don't understand is the double sided crank. Why is the left side crank crossing over to a right side chainring needed? A regular right-side crank driving the rear "hub" would have been simpler and adequate.

An interesting gadget, but they forgot the first rule of good engineering and that's to identify a problem and provide a solution. Yes, they've removed the spokes for whatever that's worth, but at a cost of higher weight and less efficiency. What's next, a "tipless" bicycle that can't fall over?

The simple fact of the matter is that the traditional bicycle configuration survived and evolved for over 100 years because it's damned efficient; low weight - especially rotating weight & low power loss, plus the fringe benefits the resilience of spoked wheels offers in terms of rider comfort and traction.

I'm not saying there isn't room for innovation or creativity, but we best move forward by building on the lessons of the past rather than trying to re-invent the wheel.

One problem with engineering students and bicycle design is that many come from the automotive world, and aren't used to the constraints of a vehicle whose engine produces less power than that used in a typical car's audio system. The reality is that it isn't the bicycle that needs to be re-engineered, but almost everything else. Imagine the potential savings if all products could be brought to the bicycle's energy efficiency where 97% of input energy produces useful work.

That's pretty damn awesome. It's about time someone took a step towards making all those concept bikes a reality.

Interesting but not novel. There have been several motorcycle wheels designed in a similar spokeless (aka "hubless") configuation

At least one car too, the name SBARRO comes to mind for some reason...

ah, here: http://files.conceptcarz.com/img/sbarro/osmos2.jpg

From an engineering perspective this usually falls into the category of "doable, but pointless". To keep the rim tracking you need very fine tolerances and fairly high contact pressure. Contamination of the trackway (where the rim is clasped) is a huge issue.

this could have a future in circus acts. combining the clown riding the bicycle with the lion (or squirrel) jumping through the hoop.

That's pretty damn awesome. It's about time someone took a step towards making all those concept bikes a reality.

Unless there is a clear, winning combination of benefits: lower cost, better strength, smoother ride, better reliability, efficiency, etc. this will remain an interesting hack at best.

Adam

Reminds me of the hubless front electric Yikebike (http://www.yikebike.com/site/home).
http://yikebike.cachefly.net/yikebike/images/yikebikestudio/yikebike0.jpg

An interesting gadget, but they forgot the first rule of good engineering and that's to identify a problem and provide a solution. Yes, they've removed the spokes for whatever that's worth, but at a cost of higher weight and less efficiency.

That's the way I looked at it at first too, but come on- it was a college student project to look at alternate ways of doing things. They were supposed to design it differently and they did. I'm sure they learned a lot about why the common spoked wheel is the current standard. For projects like this you have to judge it based on the assignment the professor assigned (in this case using a different implementation of a common machine), and not based on its market success.

They were just playin' around for a grade, not trying to rattle the foundations of the cycling world. If you read the comments you can see the problem they were trying to solve was not to accomplish some quantum improvement in cycling technology; the problem was to get them a good grade. If I were the professor here, I would also ask for an analytical writeup of what they produced; that would be potentially more educational than actually producing the project.

That's the way I looked at it at first too, but come on- it was a college student project to look at alternate ways of doing things. They were supposed to design it differently and they did. I'm sure they learned a lot about why the common spoked wheel is the current standard. For projects like this you have to judge it based on the assignment the professor assigned (in this case using a different implementation of a common machine), and not based on its market success.

Absolutely, I look at it that way, but I guess I'm a tough grader. If this were a high school science project I'd give it an A. But I expect more from a college project.

When I was in school, we couldn't get a project approved until we first justified a need and how we were improving on the current state of the art. Just building gadgets wouldn't cut the mustard. So, I'd hope that they were prepared to demonstrate that it was somehow more efficient, less costly, or otherwise some improvement on the current standards. I give them points for originality (though it has been done before) and creativity, and possibly for problem solving, but overall it's short of what I'd consider a truly worthy effort. BTW- if they had some other application for their drive system and wheel and used this only as a demonstration, then I'd give them better marks.

I also have a few questions about their thinking. For example, driving from the top of an unsupported rim (no spokes) required a rim structurally rigid enough to support the axle load. Had they put the driving spur at the bottom, possibly using a swing arm, the rim would only support weight in compression from the tire to drive spur, allowing for a much lighter rim and a simpler design. It's that kind of question that makes me give them low marks.

As I said, I'm a tough grader, but I'd hope that today's engineering schools challenged their students more and better prepared them to think critically about their designs.

someone design me a disc wheel that won't catch wind.

I'm tired of squirrels trying to jump between my spokes.

I'm tired of squirrels trying to jump between my spokes.

Incredibell Brass Duet (http://www.mirrycle.com/brass_duet.php)

http://www.mirrycle.com/product%20images%20large/brass_duet_bells.jpg

Squirrels almost always run directly away from the sound. Works like a charm.

Unless there is a clear, winning combination of benefits: lower cost, better strength, smoother ride, better reliability, efficiency, etc. this will remain an interesting hack at best.

Adam

Notice how I didn't say it was useful, stronger, or better in any way. It's just cool. Really cool.

Incredibell Brass Duet (http://www.mirrycle.com/brass_duet.php)

http://www.mirrycle.com/product%20images%20large/brass_duet_bells.jpg

Squirrels almost always run directly away from the sound. Works like a charm.

the squirrels here don't do that...

I'd hope that they were prepared to demonstrate that it was somehow more efficient, less costly, or otherwise some improvement on the current standards. . . . I give them points for originality (though it has been done before) and creativity, and possibly for problem solving. . . . As I said, I'm a tough grader, but I'd hope that today's engineering schools challenged their students more and better prepared them to think critically about their designs.

Maybe they weren't being evaluated according to any of your criteria. The ability of the end product to improve on current bicycle technology might not have been the point of the task. The point of the project could have been to learn project management, or gain experience in fabrication/design techniques, or problem-solving within a novel and unfamiliar set of constraints, e.g. 'your constraint is to build a wheel without spokes, supported from the top', or to demonstrate the application of some specific mechanical principles and theory in a functioning device.

Maybe they weren't being evaluated according to any of your criteria. The ability of the end product to improve on current bicycle technology might not have been the point of the task. The point of the project could have been to learn project management, or gain experience in fabrication/design techniques, or problem-solving within a novel and unfamiliar set of constraints, e.g. 'your constraint is to build a wheel without spokes, supported from the top', or to demonstrate the application of some specific mechanical principles and theory in a functioning device.

I agree, and I'm not the one grading their project, that's between them and their supervising professor. I'm an outsider and only a kibbitzer, and as I said I'd give them better grades on other aspects of their mission, such as originality and execution.

My comments were based on the totality of the project as an engineering/design project, where there seems to be weakness in the research into the prior art, and practicality of their concept. When I was in school, we were always challenged about the why of our designs, not only the what and how., and that's what I would have loved to have seen discussed more.

Given that spokeless rim drive cycle designs are over 100 years old, including one where the rider sat within the wheel, they can't exactly claim novelty, so it would be nice to know what they thought they were bringing to the table.

........What I don't understand is the double sided crank. Why is the left side crank crossing over to a right side chainring needed? A regular right-side crank driving the rear "hub" would have been simpler and adequate.

It's to gear up the chain speed. If you think about it the cog belt inside the rim is like a rim size rear sprocket. To get the wheel to turn at the proper gear inch value the step up given by using the middle crankset as a jackshaft is required.

There's SO many shortcomings in this as a valid system for a viable bicycle that it's not funny. But since we don't know what the rules were that they were operating under we can't know what they were trying to achieve and why they went with this option. But they got it running after solving a lot of sticky issues I'm sure.

It's to gear up the chain speed. If you think about it the cog belt inside the rim is like a rim size rear sprocket. To get the wheel to turn at the proper gear inch value the step up given by using the middle crankset as a jackshaft is required.

There's SO many shortcomings in this as a valid system for a viable bicycle that it's not funny. But since we don't know what the rules were that they were operating under we can't know what they were trying to achieve and why they went with this option. But they got it running after solving a lot of sticky issues I'm sure.
Thanks, I saw a discussion about this design on another forum and the gearing issue was explained. I should have seen it before I asked. :(

of course this bike wasn't made for practical use!
it's just a project by college students to mess around with. The frame looks heavy enough to support a 250cc or 125cc dirt bike engine LOL

Cannondale had something like this 15 years ago. There is nothing new under the bike sun.

One problem with engineering students and bicycle design is that many come from the automotive world, and aren't used to the constraints of a vehicle whose engine produces less power than that used in a typical car's audio system. The reality is that it isn't the bicycle that needs to be re-engineered, but almost everything else. Imagine the potential savings if all products could be brought to the bicycle's energy efficiency where 97% of input energy produces useful work.

True dat. My brother is a gifted mechanical engineer and cyclist. He was always at intellectual odds with his coworkers about designing things from a cyclist's standpoint rather than an automotive one. The other engineers are always trying to find ways to make bicycles more like motorcycles. His ideas were more like "why do they use motorcycle-style suspensions on bikes?" He had one idea to put a pivot point just in front of the bottom bracket and spring in line with the top tube, having the top tube slanted down instead of up. It would offer most of the same suspension benefit as a rear suspension bike, but at a much lower weight and simpler design.