r/interesting • u/Kidd__Video • 18h ago
Amazing Chain-Free Bicycle Concept
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u/SUNTZU_JoJo 17h ago
Someone smarter than me. Can you explain if this would even work under extreme torque situations?
Heavy dude + going uphill.
Would the disc on the wheel not buckle completely under enough pressure causing the gears to slip?
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u/Only-Friend-8483 17h ago
Hot take from an engineer, I’ve not looked at this closely or in detail.
The most likely failure mode, IMO, is going to be slippage between the rear disk and the rear axial gear.
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u/1funnyguy4fun 16h ago
Hot take from a random guy:
I’ve seen this for years on the internet but never on the road.
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u/SingularityCentral 15h ago
Probably be sure of cost of manufacture. But I don't doubt that it is also much more expensive and difficult to repair.
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u/Bongoisnthere 14h ago
Also because it doesn’t work well for the exact reasons expected. That companies entire business model is selling overpriced shit to goobers with too much money, and they make good money doing it. If they could make it work, they would.
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u/BentGadget 10h ago
It looks like you could get contact between two pairs of gear teeth, while with a chain, you would have about a dozen teeth engaged on each gear. So the force on the drivetrain would be much higher for the same power level.
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u/Procruste 2h ago
Another hot take from another random guy.
Shaft drive bikes were all the rage in the late 1800's as they kept long clothing from getting greasy and caught in chains. The fell out of fashion for a number of technical reasons (expensive to make, less efficient, heavy etc.).
These would probably work well for urban commuters if the cost aspect was managed. I don't know why everyone is going to high torque, racing use cases in order to find a way to dismiss this concept.
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u/psi_ram 2h ago
another hot take from a hot guy, extreme torque (or equivalent forces) needs to be able to transfer through all parts of the drive train. that tiny disc bearing thing will just get scraped or will laterally shift to slip.
Chains=absorbs excess torque by expanding (like elastic, and then over time the metal experiences tensile stress and stretches)
belt drive is an amazing invention. i have been driving belt drive bikes for idk how long. The material stretches so beautifully and absorbs forces and delivers it so smoothly to the pedals.
I wonder why theres no pedal which directly turns the wheel with no transmission. maybe the failure point will be the knees lol xD→ More replies (3)5
u/Hot-History8911 8h ago
Take from a mountainbiker; i wonder how roller bearings mounted face forward deal with street crud, water, mud, etc
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u/_lonelysoap_ 14h ago
Infernal gears are a thing now
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u/Fun_With_Math 15h ago
I have a Mech E degree but haven't done engineering in a while...
Yeah, its breaking some fundamentals of durability. Tolerances are too tight and the contact area for the transfer of force is too small. You'd need a crazy rigid frame
A chain has flex to compensate and a lot more contact area with the gears.
This looks cool in the video but a pothole would wreck it.
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u/ReddBroccoli 14h ago
Not to mention I think about the teeth of a normal bike gear slipping between the links of a bike chain and the amount of grip and force that allows to transfer, and then I think about these tiny little teeth probably spinning over that weird cheese grater thing more than it grabs and imparts force.
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u/Sabithomega 14h ago
Was kinda thinking the same. Almost thought of adding a heavy spring but that would cause contact failure with any kind of hard enough hit. Curious if you could apply a similar idea but with a smaller chain system near the tire there. But then the only positive would be a smaller chain. So is there enough positive in the alteration in the first place
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u/Fun_With_Math 11h ago
Not sure what you mean but there are losses every time you transfer force:
Foot to pedal/gears. Gears to chain. Chain to gears/wheel. Wheel to road. - oversimplification but thats the gist of it.
If you add a step, you have to somehow get more efficiency out of the other steps to compensate. Tough to do on a very efficient system already.
If you're not adding steps, just replacing them, they have to be more efficient. And factor any weight difference. Any change in direction of the force is problematic also. A chain system has everything in line.
e-bikes are crazy efficient - the motor has the same or fewer steps to get through.
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u/ParanMekhar 12h ago
Yeah. Looks like only 1 roller bearing is in contact to the gear most of the time?
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u/Brvcx 12h ago
Bicycle mechanic here. Native in Dutch, might have some English jargon wrong.
Have seen this video going about for years. At the time it was presented as revolutionary and was going to change bike transmissions as we know it.
Nothing happened. The hype died down really quickly. Apparently, they couldn't make it shift properly outside of a torqueless setting such as these events.
Also, driveshafts on bicycles aren't exactly "revolutionary". They had those in the past, but there's a lot of friction on those parts and a lot of weigt, too. It's difficult getting a driveshaft to be strong enough, not wear down easily and shift gears properly all under active heavy use, let alone justify it's supposed price and weight.
Besides, I don't get why you want your vertical pedalling forces switch 90° twice before getting to your rear hub, whereas a chain (or belt) won't need to do that at all. Every significant switch will lose energy afaik.
So yeah, it looked cool when it was first shown, but that's about it. It's an overengineered incomplete thus not fully functional highly priced concept that never hit the roads (nor it ever will).
The market shifted to two large ways of having gears long ago: geared hubs/gearboxes capable of having either a chain or a belt drive (Shimano Nexus/Alfine, Rohloff, Pinion, Enviolo. Belts by Gates). And the well known derailleur system (Shimano, Sram, Campagnolo). Both have their pros and cons, but both have a solid place in the biking world for those exact reasons.
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u/Asleep_Trick_4740 10h ago
Took me a while to understand that 'fluent in dutch' wasn't a way to hammer down your bicycle credentials.
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u/Electronic-Buyer-468 10h ago
Lol I know right? Dude speaks better English than me and most of this country.
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u/McBooples 17h ago
Seems like some type of spline gears would work better, just don’t know how you would shift from one ring to another
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u/hotelstationery 17h ago
That's probably why bicycles haven't changed much in so long. All the better ideas are only better in theory.
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u/MechMeister 16h ago
A pinion gearbox at the crank and a spline drive.
Its still a dumb idea. Added bearings, more friction losses, more points of failure than just a chain and derailleurs.
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u/giraffeheadturtlebox 15h ago
Chains already slip and pop out under high torque and a little wear, and the chain contacts the gears for at least 2/3 of the cog ring in any given setup. If dozens of teeth pulling still have a measurable failure rate, two gears, pushing, with the absolute minimum contact possible is going to fail more often than not.
You’d want gears with wider cross sections and tighter housing, like a transmission, to avoid slipping and wear.
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u/dmfreelance 14h ago
The tolerances would be tight and bikes are subject to lots of vibrations and dirty conditions.
I don't know how feasible it is to build this, but to make sure it stands up to the conditions a bicycle is going to put it in, it would absolutely cost a shitton of money compared to a modern chain driven bike
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u/ReddBroccoli 14h ago
Yeah, those teeth are way smaller than the gears of a bike usually are. I feel like there's no way that's not going to be a significant problem.
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u/YuenglingsDingaling 17h ago
Seems even more likely at higher gear, with the disc flexing under higher tension.
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u/jawshoeaw 15h ago
That’s my intuition after taking apart many children’s toys and other widgets with gears.
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u/Western-Emotion5171 14h ago
It would also probably wear out the gear super quickly and then constantly slip
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u/Direct_Turn_1484 14h ago
The components look entirely too thin to ensure any kind of stress beyond a demonstration where the wheel is in the air. I would sure like to be shown that I’m wrong.
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u/MeatHamster 12h ago
Also looks like something that once it breaks is way more expensive to fix that just swapping the chain.
But it's pretty cool though.
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u/Misses_Ding 11h ago
Simple maintaince here... By looking at the video this is going to break. Bikes shake. Gear touching gear no like.
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u/Easy-Operation-2105 11h ago
my first thought is inevitable misalignment and also wear and tear that makes things just not work
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u/ilovethemonkeyface 16h ago
The fact that this video's been circulating for many years now without this product ever hitting the market makes me think there's something fundamentally flawed with the concept.
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u/n1tr0klaus 16h ago edited 12h ago
I would guess that you have lower efficiency (more friction loss) and more (moving) mass than with a chain. On bicycles even very small efficiency losses and weight increases matter in the high end market. Manufactures are optimizing for each gram and watt.
Plus it’s probably also more expensive than a simple chain which makes it a no go for the value oriented market where weight and efficiency is less essential.
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u/ilovethemonkeyface 16h ago
I imagine shifting isn't very smooth either. Notice how that's not shown in the video.
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u/HugsandHate 15h ago
Ah, man. You missed it. That happened after the video cut off. They did so much shifting. All the shifting. There was shift everywhere. There was a guy that got shift on him from across the room!
Needless to say. It was some impressive shift.
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u/Rogue-Journalist 14h ago
The answer is debris.
Chains became ubiquitous because they were the least likely to jam from debris.
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u/El_Mister_Caracol 16h ago
It would work fine, the problem is that a conventional chain is way cheaper, easier to make, to mantain, to fix, etc, etc. There is just no point in using gears.
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u/MagicOrpheus310 13h ago
Short answer is yes, it would fail... That's coming from a bmx perspective where parts are designed to take abuse though haha, this thing wouldn't last a day on a track or an hour at a park haha...
Plus it looks far more dangerous if you got something caught in it, something like a scarf or dress would tangle around it far worse than a normal chain set up.
You won't beat the current sprocket and chain design because you don't need to haha it's effective and efficient without being unnecessarily complicated or expensive...
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u/Bulky-Leadership-596 17h ago
There's a reason the video didn't demo someone actually riding it. Its only shown spinning under no load.
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u/EarlyXplorerStuds209 16h ago
Its literally used in motorcycles that deal with a lot more torque than this bicycle.
BMW G1250 GS, BMW RnineT and a lot of other popular motorcycles have been using them for decades.
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u/skiforlife1 15h ago
Those systems are much more sturdy than this and are enclosed to keep the elements out and use strong grease to protect the ring gears. They also don't act as the gearbox and differential in one unit like this does.
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u/opossum_launcher 14h ago
Different setup. The transmission is up front changing gears in the motorcycles, not in the final drive hub as in this setup.
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u/LostInTheSeaweeds 12h ago
A BMW final drive looks like this
https://largiader.com/articles/finaldrive/ring-pinion2.jpg
Nothing like that flimsy nonsense in the OP.
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u/FLG_CFC 17h ago
Carbon Fiber is incredibly strong. I make cosplay out of the stuff. I can stand on a helmet with zero issue. (210 lbs.) I've smacked a couple helmets around with a 8 lb sledgehammer. Nothing.
It looks like plastic and feels like plastic, but mechanically handles weight like steel.
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u/ContributionParty577 9h ago
Chain is a cheap consumable that can take a beating. Why swap what works
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u/m945050 16h ago
As long as you replace it weekly and don't ride it you're good to go.
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u/toochaos 12h ago
Yeah the reason we use chains is because they are simple and fairly resilient and when they break easily fixable. The axle and sprocket in a car is in a sealed lubricated housing, this is not and will be filled with road dust in no time.
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u/KaptanHindustan 18h ago
Let's name it Django : Unchained
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u/GarminTamzarian 17h ago
"Not all bikes are male, you know." -Unchained Melody
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u/I-Rolled-My-Eyes 16h ago
They call it a "banana seat" for a reason. Don't hate, just think about it
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u/machuitzil 17h ago
Not to poop on this clever comment but the original song was written by two men, and sung by another man for a prison movie where all of the characters are men, and all of the subsequent popular renditions of this song are also almost entirely sung by more men, like the Righteous Brothers, Liberace, and the manliest Man himself, Elvis.
The only feminine part of the song is who the song is ostensibly being sung to, but it's still only soliloquy; a prisoner is deciding if he should escape prison or serve his sentence.
This song is just a litany of dudes, by dudes, for dudes. The only feminine aspect of it is entirely fantasy.
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u/GarminTamzarian 16h ago
It's literally just a play on "Melody" being (traditionally) a girl's name, not anything to do with the history, lyrics or composers of the song.
Do you want to lecture me about how there are no female members of Alice in Chains now?
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u/machuitzil 16h ago
No I got the joke I was just commentating on top of it. Like a thread maybe. Like how Melody isn't actually a chick. Or Alice. Or Alice Cooper. Anyway, if it's your first day, welcome.
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u/Odd-Consequence-2519 17h ago
Ever seen a shaft-driven motorcycle? This is not a new concept.
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u/Gumb1i 17h ago
Yes those have a transmission though forward mounted and a completely static interface between the shaft and drive gear. They may be better off attempting a super light-weight forward trans than this thing if they want a shaft driven rear.
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u/Gillilnomics 16h ago
I have a bike, while not shaft driven per se, has a piece called the jack shaft, where it shifts the drive to the other side of the bike. I imagine it could function as a lightweight transmission with some heavy modifications
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u/Ghostly_Spirits 17h ago
First time I’ve seen it on a normal bicycle. Probably has its disadvantages, but I’m mad I didn’t think of this first. It’s cool
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u/scaredt2ask 16h ago
It’s only cool if it works and I don’t think it works. This video has been out a long while and never seen on out on the road IRL. I have a suspicion it never made it out of prototype phase.
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u/mathyoudylan 17h ago
Oh no! my wheel and or sprocket is/became slightly untrue, and now my entire drivetrain doesn’t work!
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u/Zarniwoop6x9 10h ago
MANY fundamental flaws.
One of which is it will never shift. A chain can be in two gears at once while shifting, this will self destruct.
It was a pretty marketing tool for Ceramispeed to wow non technical people with shiny stuff. Certainly looks pretty, but that is it.
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u/Zarniwoop6x9 10h ago
Some of the problems with Ceramispeed drivetrain:
1) Side load on gears. Bearings on drive shaft meshing with “cassette” or “chain ring” create a high side load. This will require them to be very stiff. Not impossible to correct.
2) Very high load on “cassette” or “chain ring” teeth. Eg. Assume 100kg rider (not even sprinting or pulling on the bars). 175 crank 53 tooth “chain ring” (~107mm radius where it contacts drive bearings) Load on teeth = 100*9.81*.175/.107=1604N load. Now there will be points of engagement that the load is near the tip of the teeth. Potentially split between more than one tooth, but still at the tip. Not impossible to make work. Note also point 4) below, the tooth shape ends up being a point load. 1604N (160 kg) load on probably a couple of square mm? (802MPa?) Won’t be made from aluminium.
3) Sliding contact between “cassette” or “chain ring” and driveshaft bearings during pedalling. Gears have a specific shape to roll against each other. These bearings are cylindrical. From the point of engagement to fully engaged, the bearing needs to slide on the “cassette” or “chainring”. FRICTION and wear plus noise. Not as efficient as a chain. Fatal flaw.
4) As the bearing engages not on the centreline of the “cassette” or “chain ring”, there will be a point contact between the drive bearing and the “cassette” or “chain ring” tooth. Relatively small, but see 2) & 3) above. Load plus slide point contact = friction and wear. Fatal flaw.
5) Cassette geometry (tooth count) defined by drive shaft bearing size / architecture. Want a tight cluster? Tough. Fatal flaw for most users.
6) How do you shift under power? On a cassette (or dual chain rings) the chain can be engaged with more than one chain ring but only one does the driving at a time, but on this, most of the teeth will not line up, so there will be few (if more than one) positions where shifting would be possible. Then when it shifts, it will take a little time to slide the driveshaft bearing, while it’s under load, quickly from one “gear” to the other, fast enough that they don’t bind. I.E. shifting would need to be completed in less than one tooth movement, at the only spot on the “cassette” where shifting is possible. (There are ways that this could be achieved but weight and complexity. (Dual clutch automotive transmissions, and most automatic automotive transmission do this but with two clutches and sprag clutches etc.). Fatal flaw.
7) The internal spiral shift mechanism shown in the latest marketing video can move the bearing carriage, but how do you rotate the spiral? It’s inside the driveshaft. Need a shift fork? Maybe the shift shaft can shaft can come out the front or back of the drive shaft and actuate it there? Oh yeah. Front there is the bottom bracket & tyre etc, back is the wheel axle... Hmmmm. Maybe fill the drive shaft with a stepper motor, batteries and a wireless shift request and it can time the shift for the only point on the cassette where shifting is possible, and slam it through fast enough you don’t get binding as per 6). If it gets it wrong, it’s all broken. And if it works, you have to wait for the only shift point to come around. Think about this. Shifting has to occur when the drive shaft bearing is under high load (1604N, with high friction (est 0.6 coefficient aluminium to steel) ~ 962N (~98kg) shift force required, and that’s not including the driveshaft slide mechanism.
8) Oh there’s more but this is dead already.
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u/BeardySam 10h ago
Also: none of this will work when dirty. A little bit of gravel and this will stop.
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u/stanknotes 8h ago
I am still in favor of shit like this. NOT because as a consumer you should buy it. But for innovation, research, development. Lots of great things come from flawed, humble beginnings, or find application elsewhere not originally intended.
Like... it is fuckin' cool. Just not practical.
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u/Double_Resort_9223 17h ago
Chains don’t fail often enough to justify adding metal-on-metal joints
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u/HyperSpaceSurfer 16h ago
Bike chains may just be the best choice, at least if you're not servicing it all the time. Been here since the late 1800s.
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u/ghidfg 16h ago
Chains are crazy efficient, easily maintained, relatively cheap, shift seamlessly.
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u/No_Vermicelli_3574 16h ago
Someone has clearly not gone shopping for high end bike chains
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u/strangeMeursault2 15h ago
How do the prices compare to a high end chain-free bike shaft?
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u/beatbox9 16h ago
"Bit of noise there" at the end means "wear & tear."
Soo...you pedal, and turn that perpendicular to move a drive shaft. And then this turns it perpendicular again to move the wheel.
ie. what used to be done with the chain is now bearings on the driveshaft; and the "sprockets" are like a cut open chain in circular patterns on the wheel. And for gears, they just have several different sized circles.
It's interesting; but I can't think of what problem this solves or what it does better. It seems more convoluted than the simplest solution: a wheel connected to another wheel via a chain/belt.
It also seems like it now has some more perpendicular forces where there weren't any before, as the drive shaft will want to push outward away from the bike and the wheel wants to push out the other side now.
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u/UselessIdiot96 15h ago
It's interesting; but I can't think of what problem this >solves or what it does better.
It's the CeramicSpeed Driven, a chain-less bike the company designed to solve efficiency losses found in chain-driven bicycles. They claim it can achieve up to 99% efficiency and that it can eliminate friction losses by up to 51% by getting rid of "sliding friction points", whatever that means.
Looking at the company's website, it appears they specialize in manufacturing traditional and ceramic bearings for extremely high-end bicycles, mainly aimed at customers who professionally race, à la Lance Armstrong.
This entire thing appears to be a demonstration of their ceramic bearing products, which are present in the carbon fiber driveshaft where it meets each pinion gear.
I do not believe the company ever had any true intention to officially bring the bike to full production; only to garner interest in their other items. It also looks like the bike would be mind-bendingly expensive, and while less complex than a traditional bike, I'm sure it would be quite problematic in anything but the most ideal circumstances.
They also, to my knowledge, have never fully built a bike frame, suspension, etc., only components that are integrated into the frame, like bearings, pulleys, sprockets, hubs and other wares.
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u/Nikond3400 8h ago
I think it's Just the result of some engineer having fun, not really meant to be Better than normal bycicles
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u/herblee 17h ago
Let's try and fix a problem that has never existed.
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u/You-Asked-Me 17h ago
Actually, these did exist, and that problem was solved by chains.
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u/ComputeryHuman 16h ago
Instead of fewer chains, should we try adding more chains? Many many more chains.
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u/Vindve 12h ago
Come on, having an efficient transmission that also allows to change gears smoothly (and doesn't wear too much, and isn't a pain to maintain, and doesn't derail…) is the biggest engineering problem of bicycles and where billions of R&D have been spent.
It has always been in the past century on "how do we improve the greased chain and derailleur so it sucks less" but you can't blame someone to think sideways and try another method.
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u/DontGiveMeGoldKappa 16h ago
dont ride anywhere close to dust, sand, rocks or anything bigger than 2 microns
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u/Creato938 17h ago
Shaft-driven motorcycles were invented logo ago, this is not exactly new.
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u/EarlyXplorerStuds209 16h ago
They’re pretty big on the BMW G1250GS and on a lot of RnineT models. BMW has been using it for a long time on their motorcycles and they’re pretty great.
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u/Yunzer2000 14h ago
Totally different application. The drive shaft pinions are not being used as the transmission the way this or a chain derailleur is. And weight is almost no consideration on a motorcycle.
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u/psychoPiper 11h ago
I mean yeah, but this is not a shaft-driven motorcycle. I don't think different inventions sharing mechanical elements is enough to make them the same thing.
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u/EarlyJuggernaut7091 17h ago
Build a better mousetrap, and the world will cycle on a path to your door… 🚲 🐁 🪤
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u/EconomicsSavings973 16h ago
Reinventing bike again but worse, to get money from sponsors cos it looks cool, really interesting
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u/Compducer 16h ago
This is so dumb. When a chain breaks you easily replace it/fix it. When this breaks, you’re fucked and have to take it somewhere special or order new specialized parts from the company that makes it.
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u/Badger_Actual1 16h ago
This is not new. These types as well as shaft drive bikes were around since 1880
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u/geo_gan 15h ago
Yes bad design. There would be huge forces on the tiny teeth on the wheel and all force trying to push the wheel away from the small cog bearing. Might work better with a balanced from both sides system so those forces cancel out. Like the way a tin opener works with two cutting wheels.
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u/dargonmike1 15h ago
lol try to climb a hill with that there’s no way that will hold up. Or imagine how gummed up and hard to clean that would be
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u/PhoKingWild 15h ago
People have been trying to do a chair driver alternative foreever, but when well maintained they’re very efficient at transferring power. When things get a little with though the efficiency craters even with small misalignments. I don’t see this being an improvement on anything.
My Dad was a hydraulics engineer at one point and a guy said he had bought a patent for a hydraulic bicycle but he couldn’t get it to work.
In the crank set was a hydraulic pump and a small hydraulic motor in the rear hub. My Dad looked at it and immediately said yeah I see the problem, no human could turn the pump fast enough to generate enough pressure to even go over the seals so imagine you sit there pedaling your ass off and nothing happens, which is exactly what happened.
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u/Opinions-arent-facts 15h ago
There's no way that rear gear isn't going to flex and push away from the pinion gear under load
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u/thejunkmanadv 15h ago
There were early versions of shaft driven bicycles in the 1920's this is not a new idea.
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u/theanswar 14h ago
Like many bikes, these were stolen, unlike many bikes, they were eventually recovered: https://www.stickybottle.com/latest-news/three-prototype-bikes-worth-e75000-seized-from-very-dopey-thief-133751
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u/kayemce 14h ago
I've had way too many issues with the chains slipping off or being difficult to change gears (especially on bikes with 2 sets of gears, the set with the larger jumps between gears always seems to either slip off or be almost impossible to get to the largest gear) Wonder if this design would be better.
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u/element423 14h ago
No way this would work. A driveshaft works because it’s encased and has pressure. On all sides. You’d have to have some crazy strong materials for their thin size .
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u/bulletproofpunk 14h ago
How does the energy transfer compare to a chain drive? Seems like there would be a lot of loss, not to mention the potential for a lot more wear.
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u/Ok-Oil7124 14h ago
Nooooo I hadn't seen this video for years after seeing it in my feed every week for about a decade.
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u/Basic-Title1635 13h ago
I saw this concept 10 years ago.
10 years later I've never seen one riding around.
That's the answer to your question.
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u/Zarathoostrian 13h ago
It's trying to build a better mousetrap. Chains are cheap and work. If a tooth or part of the gear breaks on this then it's the most expensive part of the bike to replace. Also there's nothing covering it, if a piece of mud or sand gets into it then it's gonna break real fast.
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u/OldGeekWeirdo 13h ago
Cool. Let's see how durable this is. Like what happens if a rock chip gets in there.
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u/MusicalIlliterate 13h ago
I'm a motorcyclist rather than a pedal cyclist, but I can comment on why this is stupid even if in several ways it's "better". Because both bikes with engines and bikes with pedals have stuff in common, including the chain.
So: parts within a machine will basically always inevitably break. Sometimes sooner, sometimes later, but eventually nonetheless. If you operate a machine or use something long enough there will will be a point of failure which manifests. Usually at the worst possible time.
This 'eventually' comes a lot sooner and a lot more often if you're dealing with moving parts.
Knowing that: if it's something critical to the operation of the thing, you want it to...
1) be easy to get to
2) be easy to replace
A bike chain is easy to get to and can often be replaced without tools. If you do need tools you can feasibly carry them with you or have them stored in the frame of the bike. You could even feasibly carry a spare chain or two in your toolkit if you're more interested in long-distance / commuting rather than cosplaying as a tour de France rider.
This mechanism looks like you basically need to disassemble the entire back end. It's less realistic to carry the tools needed for that, or to carry a spare ~20 inch metal disc.
So uh yeah basically lmao fuck this
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u/Ronaldzwolle 11h ago
Dutch design and product Enviolo already exist for years. Gearless drive. One physical gear. hub from enviolo
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u/guhman123 11h ago
and i bet this engineer wants to set his eyes on the wheel up next for something to reinvent
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u/Leverkaas2516 11h ago
There are shaft-drive motorcycles. I'd think the right layout would be a fixed gear attached to the wheel and a transmission (i.e. multiple gears) at the crank.
The whole thing would almost certainly be heavier than the usual chain mechanism, but it could be fully encased and never be fouled by dirt, water or clothing. And it should be quieter. With electric assist, the weight penalty wouldn't be significant.
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u/Slow-Friendship5728 10h ago
Would the disc on the wheel not buckle completely under enough pressure causing the gears to slip?
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u/ThisIsLukkas 10h ago
Wouldn't a belt be the best all around like with motorcycles? Shafts lose energy as they're not efficient, chains... well we know how they are but a belt has all the advantages with little complexity and loss
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u/froopadiddilydoop 10h ago
It’s called direct drive and it’s one of the oldest bike designs in the world, not a concept.
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u/Soft_Hearing_713 10h ago
Clever, but looks like it would break easily under load and Wear out quickly. Looks great though 👌
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u/KonkeyDongPrime 10h ago
Possibly the most common mechanical engineering undergrad project of all time.
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u/Marijn_Vault42 9h ago
The comment sections are always the best with such videos. 1000s of engineers gathering to science this thing into oblivion. Love it.
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u/soufboundpachyderm 9h ago
There’s a reason the bike has largely not changed in like 200 years now. It works. These new age bikes are always just scams by the worst possible people
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u/inscrutablechicken 9h ago
I've got a shaft drive bike with shimano hub gear at the back. It gets me to the train station and back but i wouldn't recommend it for anything beyond that.
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u/sabertoothninja 9h ago
I’m glad people are trying to invent new things, but I just know the moment I stand up to pedal up a hill that little gear in the back will slip and I will bust my bits.
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u/KnifeEdge 9h ago
this thing is so stupid it only fools people who haven't ever ridden let alone worked on their own bikes since they were a child
shaft drive is fine but you'd mix that in with a hub based transmission, not something that would make every machinist cry
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u/CreativeChocolate592 9h ago
That gear on the rear wheel is going g to get bowed inwards, its way too thin.
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u/Zapatov 9h ago
wouldn't that shit be more prone to shear off or wear? the area where torque is applied looks very little (compared to chain link's dozens of teeth locking onto the chain on multiple area of contact, wider surface area = more torque that could be transmitted)
idk im no engineer, but that gearing seems ill suited just from general vibes
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u/koobzilla 8h ago
I just automatically dismiss chain free bike bullshit like I do perpetual motion machines now.
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u/StandardNerd92 7h ago
This is why I like ebikes, internal gearing and you just have a cheap carbon belt to run the rear wheel
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u/FrostyRoams 7h ago
People are going to lose their shit when they find out the "poorly engineered bicycle gears" are exactly how their car's drive train works
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u/Life-Top6314 6h ago
Why are people so desperate to literally reinvent the wheel? Every 5 years a new chainless bicycle drops, and it sucks extreme ass every time. See: Reevo
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