I really look forward to seeing this in the real world once you've figured out the remaining challenges. All the issues I can see look solvable, which is really promising.
Author — FunnyHacks
I really like the concept. I think thirteen speed is a good sweet spot. I suspect some type of dashboard transmitter/receiver would be required. My biggest concern would be when coasting. A neutral position seems like a must for free coasting. Having an option to use my legs or handbrakes for stopping would be cool.
Author — 007vsMagua
Keep it up. Can’t imagine all the hurdles you have already overcome. Looking at this prototype, it looks like flex could become an issue. If so, milling the gears into the rear tire itself might be an avenue to approach. Swapping rear tires would give you all the gearing options you need. As for the driveshaft, it could also be a more integral part of the frame. In other words, if this doesn’t work as you have envisioned it, instead of tweaking your design, maybe tweak what the bike itself is. Best of luck to you.
Author — Armyof Shea
That system shows a lot of potential. Especially if you can get it to last long enough to make it economical enough to ride every day.
Author — Indonesia America
Looks pretty. Wonder how long it would last if Marcel Kittle or Andre Greipel were applying power in this system during the last 50 meters of a sprint? Happy to see innovation. I am sure the engineers involved in this project can solve problems that arise. If it ever comes to market, I see it applied only in very high end machines.
Author — Finley Currie
super-genius...it really is, and great video-coverage on what has to be the way of the future. taming parasitic-drag has always been the determining factor in way more than bikes, in engineering in general...and my favorite part of the video was the actual durability-test in the field for a real-world comparison lol. but im sure in time, this design will permiate bicycling.
Author — charlotte quillen
How hard would it have been to put peddles on it and have someone demo it on a roller? Ah, that would have shown how weak the rear gear hub was! Nice idea though.
Author — Mark
Excellent explanation !! I would like to have seen a rider on stationary rollers demonstrating the shifting process. Is it legal to use in professional races? other than reduced frictional losses is there mechanical advantage? also, when changing the pinion diameter to get a new set of ratios, how does the shaft adjust itself with respect to the frame? would have been nice to see the process of R & R of the shaft and pinions. lastly, what is the projected cost and can it be retrofitted to current frames?
Author — abz1248
I think it's an absolute kickass invention! I do have a few questions how does it handle torque? And how soon do you think it will be when you overcome the hurdles of Switching gears? Oh and but of course cost Factor?
Author — Daniel Hillwick
Looks like it might be a good idea...will watch this one! Will depend
much on its final execution. The design you're showing for the internals I believe will
be too slow ...heh!
Hey guys, add a solenoid coil into or around the tube, turn the whole
body into a solenoid and index it that way..with a zero energy latching system (so its not using energy while in a certain gear).
If as well with some clever engineering, you could make this device charge its self (or more).
Use the 'reverse spin' to generate electricity by latching/cogging the front roller assembly.
You can then generate electricity when its in 'spin/coast mode'... when the biker is rolling forward and holding the pedals stationary.
Author — B James
Awesome design!
I personally would like to see a soley-mechanical, torque-based automatic version, with a spring running through the center where the current "brains" are, that would get pulled with increased torque towards the front crank, shifting to lower/easier gears. The spring could get pulled by the front crank, if you press extra hard on the pedals, it temporarily transfers more torque on this spring, pulling some hard line running through the center of a compression spring? Not sure how the sprinning front bearings could transfer that to puling the spring down, hmm, maybe it could be spinning the spring, and then locking in at a torque threshold? Hmm, seems like it could work somehow :)
Author — Michael Reed
It won't work under load. The entire load is on one little aluminum tooth at a time. Another huge problem is that as soon as you put load on it the rollers will put pressure on the sprocket to move it away from the rollers. That flimsy aluminum would soon bend. And then there is the problem of changing the pinion diameter. If you do that you have to move the pinion either closer or farther away from the sprocket.
Author — bombero42
My only question, How do you control flex? The drive sprocket looks beefy enough, but the rear one looks very thin. Even if you use an exotic materiel like magnesium or titanium, there isn't enough mass to prevent a lot of flex and eventually breakage
Author — crazyjr
Amazing, great to see new tech. Keep up the good work guys.
Author — Jonathan Collins
Very interesting concept. Looks like maintenance would be greatly reduced as well (no more chain oiling - yay!). Would be fascinating to see it in action at some point. Just ignore all the Negative Nancies here - some people can do nothing but find fault with everything. Every good idea has to start somewhere and improve with each iteration. Not sure if this even needs improvement though.
Author — Maynard the Miser
I want one on my bike! Definitely the right approach from a mechanical engineering point of view. Side flex on the back gear plate would be a trick but nothing that the right design won’t fix
Author — Glen Springle
It may be the world's most efficient when it is proven to be on an actual, bicycle that can be ridden and gears shifted. Also, a problem with the "quick disconnect" drive ratio chance is that the diameter of the drive sprocket will change requiring it to be on an axis either closer or further from the wheel mounded, driven sprocket.
Author — Scooter George
No surprise that the conceptual challenge (shifting) was the hurdle I had with a similar design about 35 years ago. I was thinking helical-bevel cut at the time. Never got past that!
Author — η
Problem I see with this system: You need very little tolerances in the concentricity of the chainrings and a high stiffness of the crank and bikeframe under load. The drive shaft can not counterbalance any tolerances or wear like a chain can do. So you need a force to push the gear to the "chainring" to prevent "jumping". A Chain creates its own force, which pushes it to the chainring. You can compare that system with a back differential in a car.
Author — Alex Meier
I think it could be improved a bit by studying the geometry of how involute gears mesh, and reverse engineering a better interface with the bearings that way. Then you'd get something silent AND reduce friction.
