CeramicSpeed DrivEn drivetrain

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10speedsemiracer
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CeramicSpeed DrivEn drivetrain

Postby 10speedsemiracer » Tue Jul 10, 2018 5:03 am

Won't pretend to know much about it but it looks interesting.

Image

The makers claim a 99% efficiency rate in power transmission to the rear...

https://www.velonews.com/2018/07/bikes-and-tech/ceramicspeed-shows-off-revolutionary-driven-drivetrain-eurobike_471747
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Re: CeramicSpeed DrivEn drivetrain

Postby Trevtassie » Tue Jul 10, 2018 8:56 am

Wow, there certainly would be some sideways flexing forces on the rear sprocket in low gears, from the ramping effect of the pinion rollers. It'd take some nice steel and some slick machining to make it work. (that's engineering speak for bloody expensive)

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Re: CeramicSpeed DrivEn drivetrain

Postby Calvin27 » Tue Jul 10, 2018 9:04 am

Trevtassie wrote:Wow, there certainly would be some sideways flexing forces on the rear sprocket in low gears, from the ramping effect of the pinion rollers. It'd take some nice steel and some slick machining to make it work. (that's engineering speak for bloody expensive)


I was thinking that too. But given we have graduated to thru axles, that is a huge step forward.

I do wonder what that would feel like to pedal though....

*Edit: And you thought a disc rotor was going to do damage in a crash? What about a plate full of spikes!
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MichaelB
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Re: CeramicSpeed DrivEn drivetrain

Postby MichaelB » Tue Jul 10, 2018 1:38 pm

Looks expensive and heavy.

And some say discs are a solution looking for a problem .....

I can just imagine the cost of the bearings and the faff required when they are buggered.

5th Horsemen, please step up ...

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Re: CeramicSpeed DrivEn drivetrain

Postby find_bruce » Wed Jul 11, 2018 8:32 am

MichaelB wrote:5th Horsemen, please step up ...

My thoughts exactly - does it come with automatic gears ?

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Re: CeramicSpeed DrivEn drivetrain

Postby bychosis » Wed Jul 11, 2018 11:13 am

I wonder how it copes with mud/rain/grit. The little bearings appear to be relatively unprotected.
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Re: CeramicSpeed DrivEn drivetrain

Postby 10speedsemiracer » Wed Jul 11, 2018 11:33 am

bychosis wrote:I wonder how it copes with mud/rain/grit. The little bearings appear to be relatively unprotected.


I imagine the spin-rate would keep a lot of gunk out of there...maybe.
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Re: CeramicSpeed DrivEn drivetrain

Postby Nobody » Wed Jul 11, 2018 11:36 am

People that could afford this probably have two other $6K to $10K chain driven bikes to ride in poor weather. Also, if you could afford this then replacement part expense is probably a very small concern. Like parts for a Ferrari.
Last edited by Nobody on Wed Jul 11, 2018 12:41 pm, edited 1 time in total.

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Re: CeramicSpeed DrivEn drivetrain

Postby P!N20 » Wed Jul 11, 2018 11:38 am

find_bruce wrote:does it come with automatic gears ?


You're jumping the gun, aren't you? They haven't figured out how to actually change gears yet.

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Re: CeramicSpeed DrivEn drivetrain

Postby Thoglette » Wed Jul 11, 2018 1:09 pm

10speedsemiracer wrote:The makers claim a 99% efficiency rate in power transmission to the rear...

...undoubtably by ignoring all the things that go wrong in bevel drive. There's reasons Ducati now uses rubber bands.

e.g. this from geartechnology
Spur gears alone already have a very good efficiency of 99–99.8%. In contrast, bevel gears and, above all, hypoids in rear-axle drives, have a clearly lower efficiency due to their higher percentage of relative sliding (Fig. 2). According to transmission type, efficiency is approximately 85–97% (Ref. 1).

(That's real world numbers, not hyper-adjusted lab demo.)

Now the picture doesn't show a hypoid but it's also not running in a bath of (clean) oil. Then there's the inevitable false neutrals between gears. Presuming they ever work out how to make it shift.

I say: "Clip, clop, clipperty, clop."

Update: The Retrogrouch is onto it and has dug up this early adopter

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Re: CeramicSpeed DrivEn drivetrain

Postby find_bruce » Wed Jul 11, 2018 2:36 pm

P!N20 wrote:
find_bruce wrote:does it come with automatic gears ?


You're jumping the gun, aren't you? They haven't figured out how to actually change gears yet.

If they can quote efficiency figures for a drivetrain that doesn't exist, why can't they make it automatic? Oh & make it fly, cause I would definitely buy a flying bike

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Re: CeramicSpeed DrivEn drivetrain

Postby bychosis » Wed Jul 11, 2018 3:39 pm

P!N20 wrote:
find_bruce wrote:does it come with automatic gears ?


You're jumping the gun, aren't you? They haven't figured out how to actually change gears yet.


Missed that bit, I was looking for how it would work and couldn't figure out how it was done considering the bit that needs moving is on a rotating shaft and there appeared to be no cables. Although a linear actuator in the middle of the shaft electrically operated and fed by hidden wires might work (and add drag)
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Re: CeramicSpeed DrivEn drivetrain

Postby Mububban » Wed Jul 11, 2018 4:16 pm

From the short video I watched, they said it would likely be covered to keep out dirt/mud etc.
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Re: CeramicSpeed DrivEn drivetrain

Postby P!N20 » Wed Jul 11, 2018 4:27 pm

Mububban wrote:From the short video I watched, they said it would likely be covered to keep out dirt/mud etc.


Geez, they're already talking a gravel model.

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Re: CeramicSpeed DrivEn drivetrain

Postby P!N20 » Wed Jul 11, 2018 4:28 pm

find_bruce wrote:cause I would definitely buy a flying bike


Image

Retrogrouch.

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Re: CeramicSpeed DrivEn drivetrain

Postby Thoglette » Wed Jul 11, 2018 6:14 pm

P!N20 wrote:Retrogrouch.

Talk about making me feel old! (It's the "Gossamer Albatross" crossing the channel, if anyone cares).
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Re: CeramicSpeed DrivEn drivetrain

Postby MichaelB » Wed Jul 11, 2018 9:58 pm

Actually, is it April already ...

The ‘quoted’ efficiency figures, are they even real or just purely theoretical.

I notice with all the pics, but is there a video ?

Actually, probably more like a “Sky” PR exercise for their ceramic bearings than anything real

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Re: CeramicSpeed DrivEn drivetrain

Postby Nobody » Thu Jul 12, 2018 8:54 am

MichaelB wrote:...but is there a video ?



I don't think it will fly. Even if I'm wrong, it will probably be prohibitively expensive for almost everyone, with extremely small (if any) benefit. So I'm not a fan. But it's still interesting to look at as a novel engineering project.

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Re: CeramicSpeed DrivEn drivetrain

Postby P!N20 » Thu Jul 12, 2018 10:49 am

^ Still wondering if it can actually be ridden.

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Re: CeramicSpeed DrivEn drivetrain

Postby MichaelB » Thu Jul 12, 2018 3:03 pm

P!N20 wrote:^ Still wondering if it can actually be ridden.


I’m not.

One of the key things (aside from May of the other 45 engineering obstacles) is the strength of the “cassette” to not bend and the bearings to pop out of the drive during high torque applications.

And whilst I can see that in the larger gears, the friction is low(er), the small cogs, due to the misalignment between the drive bearings and the cassette will be huge.

Dumb idea at best.

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Re: CeramicSpeed DrivEn drivetrain

Postby Thoglette » Thu Jul 12, 2018 3:21 pm

I'll be interested in a comparison to a roller bearing equipped chain constructed to the same standard.

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Re: CeramicSpeed DrivEn drivetrain

Postby AUbicycles » Thu Jul 12, 2018 11:20 pm

Dumb? There are certainly some unknowns and at a glance I have questions about efficiency but wouldn’t call it dumb... ideas are good and if your cash is not on the line... encouraging ideas is a plus!

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Re: CeramicSpeed DrivEn drivetrain

Postby MichaelB » Fri Jul 13, 2018 7:59 am

I rate it as dumb as there is no realistic chance of success and way too many ‘wrong’ (in engineering terms) things for it to realistically succeed and make it useful

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Re: CeramicSpeed DrivEn drivetrain

Postby JPB » Fri Jul 13, 2018 8:13 am

My dad would have described it as Heath Robinson contraption. Overly complicated and engineered for its purpose.

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Re: CeramicSpeed DrivEn drivetrain

Postby Jmuzz » Mon Jul 16, 2018 3:39 pm

bychosis wrote:Missed that bit, I was looking for how it would work and couldn't figure out how it was done considering the bit that needs moving is on a rotating shaft and there appeared to be no cables. Although a linear actuator in the middle of the shaft electrically operated and fed by hidden wires might work (and add drag)


Easy enough to move by motor or solenoid, and I think smart electronic shifting would be the only way it could work since it would have to time the shift perfectly to quickly jump between spikes at the right time when there is a gap alignment.

Plus at the price point electronic shifting would be expected anyway.

Put shifting on both front and back to make that rear plate smaller and I think it's better and more combinations, eg 5 X 5 speed.

Probably all fairly pointless because it's only ever going to be about bling.

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