CYCLINGFORUM.COM - Where Cyclists Talk Tech --- Return To Home

 

    Register FAQ'sSearchProfileLog In / Log Out

 

****

cyclingforum.com ****

HOMECLUBS | SPONSORS | FEATURESPHOTO GALLERYTTF DONORS | SHOP FOR GEAR

Return to CyclingForum Home Page CYCLING TECH TALK FORUM
          View posts since last visit

DrivEn drivetrain
 

Author Thread Post new topic Reply to topic
Pat Clancy
Joined: 13 Jan 2004
Posts: 1349
Location: Manchester, CT

7/11/18 6:59 AM

DrivEn drivetrain

Unlikely to ever be commercialized, but interesting.

https://newatlas.com/ceramicspeed-driven-shaft-drive/55364/https://newatlas.com/ceramicspeed-driven-shaft-drive/55364/

 Reply to topic     Send e-mail

Sparky
Joined: 08 Dec 2003
Posts: 16693
Location: Portland, OR

7/11/18 9:14 AM

Seems so few drive contact points would wear fast...

 Reply to topic     Send e-mail

April
Joined: 13 Dec 2003
Posts: 6420
Location: Westchester/NYC

7/11/18 4:05 PM

But ceramics donít wear out.

 Reply to topic     Send e-mail

Sparky
Joined: 08 Dec 2003
Posts: 16693
Location: Portland, OR

7/11/18 5:26 PM

The ceramics are the shaft bearings, not the drive engagement mechanism from what I read.

 Reply to topic     Send e-mail

Brian Nystrom
Joined: 26 Jan 2004
Posts: 4163
Location: Nashua, NH

7/12/18 5:45 AM

The main problems with it are:

1 - The bearings are open, which means they're quickly get contaminated with dirt and the 1% increase in efficiency will go out the window. If you put seals on the bearings, the 1% increase in efficiency will go out the window.

2 - The flat driven disk will flex under any significant torque, which means that most of the "gears" toward the outside will skip as it flexes under pressure.

3 - The tiny fingers on the drive and driven disks will bend and break easily.

4 - They haven't figured out how to shift it and it may not even be possible to do so.

This is an interesting engineering exercise with no practical applications in the real world, with the possible exception of track bikes and other single speeds. At least it's a pretty neat example of out-of-the-box thinking...


Last edited by Brian Nystrom on 7/15/18 1:01 PM; edited 1 time in total

 Reply to topic    

daddy-o
Joined: 12 Apr 2004
Posts: 3201
Location: Springfield

7/12/18 7:09 AM

Building on Brian's assessment:

The weak link is the lack of engagement, crank or cog. It's designed to slip. The force transfer surfaces are riding on balls. This thing will never pass the Wayne Lim test.

They need to slap it on a single speed and have the local talent try to strip it. I'm betting if it hits prime time it will look more like a bevel gear than this over complex design school darling.

And just use a metal shaft until you get the engineering done.

 Reply to topic     Send e-mail

Brian Nystrom
Joined: 26 Jan 2004
Posts: 4163
Location: Nashua, NH

7/13/18 7:30 AM

Bevel gears would reduce the efficiency to way below that of a chain, rendering the whole exercise pointless.

 Reply to topic    

daddy-o
Joined: 12 Apr 2004
Posts: 3201
Location: Springfield

7/13/18 8:11 AM

Yep, and because of the flexing like you pointed out it probably wouldn't be any more reliable either.

 Reply to topic     Send e-mail

Brian Nystrom
Joined: 26 Jan 2004
Posts: 4163
Location: Nashua, NH

7/13/18 2:20 PM

There are - and have been in the past - gear driven bikes available that were reliable, but they trade efficiency for simplicity and reduced maintenance. AFAIK, they've all been single speeds, unless perhaps some used internal hub gearing too, which would drop their efficiency even more.

 Reply to topic    

daddy-o
Joined: 12 Apr 2004
Posts: 3201
Location: Springfield

7/16/18 5:04 AM

4:34 Video clip of the drive train on the floor of the bike show. See and hear it with commentary that reflects this thread.

https://www.youtube.com/watch?v=rgo-yEaXDzA

 Reply to topic     Send e-mail

Brian Nystrom
Joined: 26 Jan 2004
Posts: 4163
Location: Nashua, NH

7/16/18 5:48 AM

The noise and the apparent slop in the system are not impressive and don't bode well for its future.

 Reply to topic    


Return to CyclingForum Home Page CYCLING TECH TALK FORUM
           View New Threads Since My Last Visit VIEW THREADS SINCE MY LAST VISIT
           Start a New Thread

 Display posts from previous:   


  
Last Thread | Next Thread  >  

  
  

 


If you enjoy this site, please consider pledging your support

cyclingforum.com - where cyclists talk tech
Cycling TTF Rides Throughout The World

Cyclingforum is powered by SYNCRONICITY.NET in Denver, Colorado -

Powered by phpBB: Copyright 2006 phpBB Group | Custom phpCF Template by Syncronicity