Ok whats this , how does it work , do I need one ?

Joined
Feb 7, 2008
Messages
4,573
Location
Nottinghamshire England
Hi all


Whats this called ?
How does it work ?
Do I need one ?
How soon before DannyC builds one ?

Paul
 
Joined
Apr 16, 2017
Messages
424
Location
Winnipeg, Manitoba
Well I,ve been wrong more times than I care to admit, but it appears to be a type of linear shifter. With it you could maybe eliminate the rear derailleur and just use a single sprocket on the wheel.
 
Joined
May 31, 2013
Messages
3,980
Location
South Benfleet, Essex, England, UK
It looks like a version of the chain-driven gearbox system that was supposed to be made by Hayes c.2004.

https://mbaction.com/hayes-to-market-chain-driven-gearbox-system-oct-5/

=============================================================================
snip from article......
Honda has patented a similar system for its RN01 downhill bike that reportedly has been in service with the team for much of this past season. There is no big secret to be revealed inside the Honda or the PeteSpeed transmissions?they are really just a derailleurs in a box. The PeteSpeed/Hayes system, however, does offer downhillers a couple of big advantages over the conventional external rear derailleur:

1)Anytime shifting: because the freewheel is at the crank, not the cogs, as long as the bike is moving, so is the transmission?which means that you can shift whether you are pedaling or coasting.

2)Precise drive-sprocket placement: the final drive sprocket can be placed close to, or concentric with the swingarm pivot, which helps to remove pedaling torque from the suspension action.

3)No more flailing chains: a derailleur in a box has a short chain that cannot derail easily. Conventional external derailleurs are weak chain tensioners that let the chain flap all over the place.

4)Say goodbye to muddy cogs: Only the final chin drive and a couple of sprockets are exposed to the goo and dust?and a heavier chain can be used, because it does not have to shift.

SO, WHAT?S BAD ABOUT IT?
Weight?it has to be contained inside a strengthened housing that is bolted to a frame, so it will be heavier. And, it will not cover a wide enough range of gearing to make a true mountain bike transmission in its present layout. Another disadvantage is that the small-diameter sprockets inside the PeteSpeed transmission are subject to much greater torque loads than the larger-diameter sprockets of a standard system. This will undoubtedly lead to accelerated wear of the sprockets and chain inside the PeteBox.

================================================================================

The big problem with such systems with very short lengths of captive "drive-transfer" chain is that the chains suffer from "stretch" too much because all of the load is put on so few links.

Sandman had the same problem on his e-assist drive where a captive hub-motor was used to transmit drive.

Not sure I want to build one (even for the challenge). :)

Dan.
 
Joined
Feb 7, 2008
Messages
4,573
Location
Nottinghamshire England
This looks more useful ?


It reduces the rear mech height to approx 0 , however it appears to be a pull/pull gear shift so unsure what they use to control it ?

Paul
 
Joined
May 31, 2013
Messages
3,980
Location
South Benfleet, Essex, England, UK
This looks more useful ?


It reduces the rear mech height to approx 0 , however it appears to be a pull/pull gear shift so unsure what they use to control it ?

Paul
Could be any 2-cable shifter as long as it has enough travel I guess. :)
A simple Fore/Aft lever with cables attached on either side would do it. You would only need to work out the amount of cable travel required across the range. A longer lever makes it easier to change (of course).
 
Top