Before going crazy with diagnoses, start with the simple stuff that is the common culprit.
First, you know there is supposed to be slack. More slack than many people think and do when adjusting, which when it is too tight exponentially wears out a chain and sprockets. For many the most common cause of chain stretch is that the chain is being tightened too much when adjusted.
Next, if the chain worn out to the replace area of the adjuster guide, yes a chain can stretch faster. Replace then.
Last edited by kwtoxman; 06-13-2014 at 05:53 PM.