From: jbrandt@hpl.hp.com (Jobst Brandt)
Newsgroups: rec.bicycles.misc
Subject: Re: Simple Newbie question.........
Date: 29 Sep 2000 19:13:21 GMT

Vincent Radford writes:

> What exactly is chain suck?

Chain suck occurs when the chain does not disengage from the driving
chainwheel and wraps around rips the derailleur apart in the process.
This occurs primarily with small sprockets and new chains, a
combination in which the teeth are still bearing load where they
should disengage from the chain.  Grit enhances the condition.  For
larger sprockets (30+) a new chain on a worn chinring usually
disengages with a little chatter under high torque but smaller
sprockets have so few teeth that tooth contact is high at exit and a
large reach derailleur (typical for MTB) allows the chain to hang on
beyond the line of incoming chain.  Rrrrrip!

Jobst Brandt      <jbrandt@hpl.hp.com>