Is this the cleverest bike drivetrain ever?
- Thread starter cancel2 2022
- Start date
Mott the Hoople
Sweet Jane
The radial drive train itself is not innovative but the use of composite components certainly is. Keeping in mind that this is a prototype and the devil is in the details I should point out that radial drive trains have been tried on bicycles before and have failed. Usually either because of cost, complexity or durability issues.
Though this looks simpler in design it is actually more complex adding 23 bearings and a drive shaft. How durable can a carbon fiber drive shaft be? How easy would it be to fix or replace if it broke on a ride? Same with the bearings? Under high load will the axial forces cause the drive train to skip over the gears? It looks like a serious over load issue to me as a chain is in contact with most of the cog at any given time and this is in contact with just one small part of the cog.
Since this is more complex then a chain/mech combo even it if does improve efficiency, will it be as reliable? Given the nature of the materials involved sinternig ceramic chain rings, the cost of manufacturing the bearings and a reliable carbon fiber drive shaft would probably be christly expensive. So though this looks like a fascinating concept and might be more mechanically effiecient....it's got a long ways to go to pass from prototype to proof of concept, let alone full scale production.
It would be interesting to see what Southernman's opinion would be as an engineer.
Though this looks simpler in design it is actually more complex adding 23 bearings and a drive shaft. How durable can a carbon fiber drive shaft be? How easy would it be to fix or replace if it broke on a ride? Same with the bearings? Under high load will the axial forces cause the drive train to skip over the gears? It looks like a serious over load issue to me as a chain is in contact with most of the cog at any given time and this is in contact with just one small part of the cog.
Since this is more complex then a chain/mech combo even it if does improve efficiency, will it be as reliable? Given the nature of the materials involved sinternig ceramic chain rings, the cost of manufacturing the bearings and a reliable carbon fiber drive shaft would probably be christly expensive. So though this looks like a fascinating concept and might be more mechanically effiecient....it's got a long ways to go to pass from prototype to proof of concept, let alone full scale production.
It would be interesting to see what Southernman's opinion would be as an engineer.
cancel2 2022
Canceled
It will.probably be only for top end bikes at first, it's still in the prototype stage so who knows how it will evolve?
FUCK THE POLICE
911 EVERY DAY
Kind of bizarre to have an open shaft driven bike? I think most shaft driven bikes use gear hubs.
Anyway, these are complicated, difficult to fix or get serviced, and heavier than chain drives. No thanks. Pretty cool to look at though.
cancel2 2022
Canceled
This guy gets it.
A bevel gear shaft drive on a bicycle requires a hub gear to be able to shift. That leaves you with a very limited gear range that is extremely inefficient for racing. It’s also very heavy. This design gives you the gear range versatility of a derailleur drivetrain and then some. It’s also likely lighter than a derailleur setup and certainly lighter than a bevel gear shaft by a very wide margin. The focus of this drivetrain shouldn’t be the drive shaft as much as it should be the ‘cassette’ and how it shifts. That’s where the real innovation is here. Coupled with the fact that it will be electronically controlled, and you have a vastly different drivetrain from a basic bevel gear shaft. I think it deserves to be said though, that there are certainly some issues that the engineers will have to work out, no doubt about it. Quite frankly though, if you spend more than a few seconds thinking about it, it should be pretty obvious how this is better. In fact, the two aren’t even in the same league.
https://theradavist.com/2018/07/cer...damn-cool-driven-chainless-drivetrain-system/
A bevel gear shaft drive on a bicycle requires a hub gear to be able to shift. That leaves you with a very limited gear range that is extremely inefficient for racing. It’s also very heavy. This design gives you the gear range versatility of a derailleur drivetrain and then some. It’s also likely lighter than a derailleur setup and certainly lighter than a bevel gear shaft by a very wide margin. The focus of this drivetrain shouldn’t be the drive shaft as much as it should be the ‘cassette’ and how it shifts. That’s where the real innovation is here. Coupled with the fact that it will be electronically controlled, and you have a vastly different drivetrain from a basic bevel gear shaft. I think it deserves to be said though, that there are certainly some issues that the engineers will have to work out, no doubt about it. Quite frankly though, if you spend more than a few seconds thinking about it, it should be pretty obvious how this is better. In fact, the two aren’t even in the same league.
https://theradavist.com/2018/07/cer...damn-cool-driven-chainless-drivetrain-system/
cancel2 2022
Canceled
It's a prototype and no doubt the final version will be sealed, they use coated ceramic ball bearings which are considerably tougher and more hard-wearing than steel.
CeramicSpeed are no mere amateurs, so I am sure they know what they're doing. They have been working with many of the top riders for some decades now.
https://www.ceramicspeed.com/en/sport/journal/defying-the-conditions/
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I'm sure they are not amateurs, and again, it's an interesting design. But, the ball bearings have to be extremely small (a minimum of 5 balls per bearing) and must be lubricated and sealed to be rigid. Not a cost effective endeavor for sure. Add to the fact that the contact area is so limited, again, torque is also limited.
Durability of carbon fiber for the shaft isn't an issue. They make automobile driveshafts and airplanes out of it. Single point of contact isn't either, since gears are made that way. The problem I see is that unlike a chain any bit of dirt will bind this thing so, like a gear box, will have to be sealed. Hence weight and complexity.
cancel2 2022
Canceled
Well they specialise in ball bearing technology and work with the best riders in the world, so we'll just have to see. They make the ball bearings from silicon nitride, which is far less susceptible to failure caused by dirt, dust and poor lubrication.
Like most designs, I believe it will need "tweaked." Of course it has to be expensive, I doubt the "average" bike rider could afford one.
Really cool looking.
I have the same concerns as the others about the unprotected bearings. If properly sealed...people who can afford them will buy them...just because they are there.
I have the same concerns as the others about the unprotected bearings. If properly sealed...people who can afford them will buy them...just because they are there.
cancel2 2022
Canceled
It would easy enough to put dust caps onto those bearings, can't see it being an issue.
The dust caps would need to be free floating and that causes wear problems with such a small bearing. They would also need to be made from a very durable material, UHMW might be a possibility.
cancel2 2022
Canceled
The whole thing is a gearbox...
Fentoine Lum
Verified User
Well yeah, like with all your posts, they must be swallowed without doubt.
cancel2 2022
Canceled
Do you ever make intelligible posts? How about you make a constructive criticism rather than your usual ankle biting?
Fentoine Lum
Verified User
To intelligent posts, yeah. Try it sometime. Cheers.