James Connell writes:
>> I have a SunTour chain that I need to break to throughly clean; I know that I should use a
>> replacement pin when doing so, however a bicycle mechanic told me that a Shimano pin will not
>> work. If I don't push the pin completely out will I still be in jeopardy of creating a weak link?
> Any time you push the pin out it gets weaker, on the newer models with 'mushroomed' pins get is
> worse I'd remove the link completely and put in a quick link.
The reason for the special pin for Shimano is that there isn't much of a micro radius on the ends of
their pins and pressing such a pin back in can get into a broaching mode that reams out some of the
press fit that is required to safely use the chain. The special pin is one with an entry nose with a
groove to crack off the nose after pressing in. This assures a more reliable fit, although the
radius at the groove is no greater than the original pin had. It only guarantees a straight
insertion that you can achieve yourself if you have the tool. Shimano inserts these pins in without
a leader nose in the first place.
I have not used these chains but most others that I have, I re-inserted the original pin, that is
except for the times I used master links. After one of these jumped out on me when clean and new, I
decided they offered no advantage because a dirty chain is not easily opened with one of them, grit
taking up the clearance needed to release the master link. The master links can disengage if the
chain skips on a worn sprocket and the link happens to be the next on to enter the sprocket. In that
event I found the link lying on the street, reinserted it and rode on.
When pushing out a pin for re-use, push it only so far that the chain will not separate without
lateral bending or it will be difficult to connect the chain after cleaning. When pushed back in,
the pin should protrude equally on both sides before the link is loosened by forcefully bending the
chain sideways. This bending forces the side plates apart enough to make the chain free to
articulate.
Jobst Brandt
[email protected] Palo Alto CA
