Martin wrote:
The other day the mechanic at my local bike shop rejoined my Shimano 10
speed Ultegra chain reusing two rivets. Looking at the link under a
jeweler's magnifying glass I can clearly see that the peening on the
rivets is missing and I can see the countersinking in the plates around
the rivets.

The mechanic is very experienced, very well respected and services many
bikes in a busy shop. It looks like the rivets have been inserted to the
correct depth. Nevertheless the contact area between rivets and plate is
substantially less than it should be and the peeening that would prevent
the rivet moving is absent.

I am interested in readers' opinions and experience regarding the safety
and durability of this repair job. Do many people reuse rivets? Any
experiences of reused rivets working well? or failing?

Many thanks

Martin

on shimano chain, never re-use rivets. as you say, the peened shoulder
sheers off leaving the link side plate free to disengage. always use
the replacement rivet supplied with the chain.

on older chain, particularly sram, it's not a problem as rivets do not
sheer their peening shoulders, but again, this is NOT the case with
shimano, so a new rivet is mandatory.

regarding your mechanic being "well respected", that's much more a
function of their self-promotion abilities than their actual skill or
knowledge - as you seem to suspect. near where i live, there's a guy
that promotes himself as the hottest wheelbuilder around - massive "word
of mouth" following, but having examined several pieces of his work, i
can say that it's distinctly average - more than 1mm lateral play after
100 miles, uneven spoke tensions... very average indeed. otoh, another
builder i know is quite exceptional, but he's very quiet & modest &
"road only" so he's known to a much smaller following of aficionadoes.