520 sproket/525 chain

[Andy Preston]

Randy Grein wrote:
> High milage, dirt, water, neglect...
Mine suffer from that exact problem, normally in the reverse order !  In 
this picture is a DID XVM 525 on the left, and a DID XVM 520 on the 
right. The 520 chain is new, the 525 has 37K miles on it and is only 
1/8" longer for 108 links.  I couldn't believe how little that chain had 
stretched. The 520 was too stretched to be useful anymore after around 
20K miles, and I ended up just replacing the chain and getting another 
15K out of that chain and sprockets.

http://prestonmedina.com/img_1994_scale.jpg

To Dave's original question, just buy a steel 525 sprocket, the $50 will 
be worth it,

Andy