Canaboo

I recently built a bamboo frame from slim tonkin that practically seems to pedal itself and when going through various theories and testimonials came across this.
https://www.faqs.org/patents/app/20120098233
Thoughts?

Andrew R Stewart 

The patent reads to me like a another way of saying the bike plans...

Really it is interested that companies that market stiffness have to patent flexibility.

Your "discovery' is not new. BITD we sold nicer bikes on their "resilency" The thick walled low cost bikes were actually stiffer then the higher priced light weight ones. The thin walled ones rode better to any that used them. Some of us are still riding such bikes. We know that our rides are not filled with 1000 watt sprint finishes but with the feel of a nice road and how we flow along it. Andy.

Canaboo

https://www.erbbike.com/index.html

Live Wire 

Ha, thats pretty funny. The URT + the slingshot, the hottest suspension designs from 1994 together in one bike!
Looks like it would be fun to try though, the old Slingshots weren't so bad.

fietsbob

VBQ went on and on about Planing.. just enough flex to add comfort,
but any flexibility comes back as springy rebound , returned to the pedaling forward.

Canaboo

I do notice some very heated discussions about frame flex versus stiffness.
Interesting that many pieces of sport equipment likely fall in the same category.
Here's a quote from a badminton raquet company:

The stiff racquet structure at the top of the frame head allows the head to bend in a very controlled way and hold shuttles on the string bed for longer.
The thin frame sides then allow the frame to bend more and transfer more energy to the shuttle.
This combination allows you to smash with instant power.
Doesn't that sound just like what a person convinced that a frame with just the right amount of give might do to a pedal "smash" as well?

repechage

The whole "plane-ing" claim really makes me crack up.

Do bikes "plane", front he descriptions I have read, yes. But from experience and a bit of engineering and riding some early ti frames, (Speedwell and Teledyne) the window of "advantage" or perceived advantage is pretty narrow. The bike planes, but then there is an attack, and you must answer it, and you get out of phase with the spring of the frame, your inputs vary but the spring constant does not. So, you endure. Your happy, springy frame is not helping anymore. If you can always pedal in the happy harmonic of the frame, life will be just springing. Stops and terrain don't allow that.

Canaboo

I wouldn't call a frame a "constant" spring. The harder you hammer, the more you displace the frame but it requires more pressure to do so.

Andrew R Stewart 

The question here might be is the deflection of the spring (frame) linier with the load or not. We, people, are not able to discern the difference with out measuring tools. With either a constant or variable spring, the harder you load it the more displacement will happen. How this applies to frames I'm not sure... Andy.

Canaboo

The harder you push against the spring, the harder it pushes back???
One thing you learn as a kid pushing over standing dead trees so you can yell "timber!" is that a tree with just the right amount of flex left is a lot easier to get pushing itself over once you set it in motion.

Andrew R Stewart 

--Not sure how this applies to frames, Andy.

wphamilton

I think the patent doesn't actually claim greater efficiency from the flexible frame, so all the related verbiage is extraneous.

Canaboo

The second link does and the patent is for the owner of the energy return bike...

wphamilton

canaboo you can name an invention anything you want on the patent, but the patent abstract says, "may also enhance the delivery of pedal power" and in the Background says "appears to increase energy efficiency". I look at the indefinite language - "maybe" claims are not patented.

In short, the inventor isn't trying to patent a more efficient frame. He's trying to patent a frame which yields a smoother ride. He might market it in some other fashion.

Canaboo

Doesn't the site for the actual bikes make those claims a bit more definitely?

Omiak

Man that's so weird I'm almost interested in buying one. Their over the top marketing kind makes me suspicious though.

Also there only seems to be two reviews of the thing online, one from two years ago and one from four years ago. Weird.

Mark Kelly 

The problem with all these claims is that they're a castle built on sand: since there isn't any appreciable energy loss in an ordinary frame, reducing the energy loss does diddly squat. Same argument applies to the latest carbon LSBVC wundercycle.

Canaboo

The video of the bikes on the dynamometer looks pretty convincing.
Energy loss isn't really the point but rather the practical energy gains.
I realize that energy can't be "created" but I can see relative inefficiencies of a pedal stroke being converted to a more efficient system.

Omiak

I'm not entirely sure what a carbon LSBVC wundercycle is, but you make a good point about the ERB. It does look interesting as a sort of semi-passive suspension though.

wphamilton

The marketing text does say that the spring "returns energy", but it is unclear to me that there is any mechanism to transfer the energy to the pedal rotation or wheel rotation. That's not actually in the patent so I'm skeptical. The only way I can see an improvement for energy efficiency is if the frequency of bumps happen to coincide with a frame oscillation, lightening the wheel over subsequent bumps. But that could just as easily work against you.

Sorry, but you did ask for our thoughts.

I tend to believe that it does act as a suspension with a smoother ride, possibly improving traction over rough surfaces.

Mark Kelly 

LSBVC = Laterally Stiff But Vertically Compliant.

Canaboo

Not sure where your other reply went......

Omiak

Ahh, I've never heard that one acronymized before.

Do you guys think this frame would suffer from the same negative features of other unified rear triangle suspension designs? I guess any time the suspension is pivoting along the composite rods you're going to have the pedals moving in the opposite direction as the saddle, but it seems like it would be pretty subtle on this bike.

Is engaging the rear brake going to make the suspension pivot and bounce you around?

Mark Kelly 

I decided it wasn't worth pursuing.



Pic courtesy XKCD.

Andrew R Stewart 

Mark- Well said! I usually try to use logic and physical laws a couple of times with my relies. After that I am reluctent to go for a strike three. I i had a dollar for every time someone said they have reinvented the bike I'd be rich. Like the Italian crank arms with a 90* bend in the arms. Their claims were along the lines of "the power reaches the rings before it's applied to the pedals" (or some such impossibility). Andy.