Randallissimo

Is it true once you break a Shimano 10 sp chain it's toast? I read this in a popular bike maintenance book. I have a DA chain, and I've removed it a few times, and reinstalled. Should I be worried it is going to leave me by the roadside to die? As far as I can tell there is no special link. The book says once you push a rivet out and then put it back in it is no longer roadworthy.

AEO

yes, that's true.

the 10sp, and even 8/9sp, chains are not designed so you can reuse the connecting pin.
You have to either have a reusable quick link or reconnect it with a new connecting pin.

basically the pins are shot peened to give the links extra strength at keeping the plates together and when you break the chain by pushing out a pin, you damage the shot peening. The plates in the chain can pull apart and break on you if you give it some heavy load and if the chain is worn out enough.

LarDasse74

Sort of true, as AEO says...

But the thing to rememeber is that you can break and reuse the chain if you use a new pin, which is available from the LBS for pretty cheap.

I found this out the hard way in the mid nineties when my chain broke about seven times in a month - I found out later I had been reconnecting it incorrectly.

Shimagnolo

Use a SRAM or KMC master link with it.
Or better yet, just buy SRAM or KMC chains until Shimano moves forward into the 1990's and starts including master links with their chains.

bkaapcke

Shimano won't be moving into the '90's anytime soon because there is no marketing advantage to it. Get a SRAM or KMC masterlink. Those need only be replaced when you change the chain. bk

AEO

KMC missinglink and wipperman connex are the only makers that offer a reusable 10sp quick link.

SRAM powerlink is not reusable, or at least it's not supposed to be, not that it's impossible.

shimano does offer a reusable quick link for their latest generation of chains, albeit a vastly inferior design to what KMC and wipperman have to offer.
just look up SM-CN79.

BCRider

AEO, do you have a SRAM link on that? I always thought that the whole point of the Powerlink is to make it so that you CAN reuse the link. And while I have to admit that I never read the instructions that came with the chains there sure wasn't any big red print that said that the links were one time use only. If SRAM is claiming that they are then they sure don't trust their own work since I've never had any issues at all with opening and re-closing my Powerlinks at least a hald dozen times each over the life of my SRAM chains. And they sure never seem to be any easier to open or difficult to close.

Or is this a new 10 speed issue for the Powerlinks?

Shimagnolo

SRAM 8/9s link: PowerLINK (gold or silver)
SRAM 10s link: PowerLOCK (black)

SRAM *claims* the PowerLOCK is not reusable.
They just added a tiny shelf on the edge of the slot to make it difficult to open/close.
You only need a Park MLP-1 to open it easily.

Randallissimo

This is unwelcome news as I have opened up my DA chain maybe three times over two years and could not tell you which links they are. So far no problems, but I wish I had known that before.

DaveSSS 

A small correction about the pin peening. The pins are heavily peened to create a mushroomed end, but it's not shot peening. Shot peening is an entirely different process, done for an entirely different purpose.

https://en.wikipedia.org/wiki/Shot_peening

Most of today's chains are of the flush-pin design, with much heavier peening than the old protruding pin design. If a flush pin is pushed out, it usually breaks off a ring of metal, left hanging on the drive pin. That's what was holding the pin in place.

stonecrd

Surprising that you are still using a two year old chain but you should replace it. Shimano is very clear in the instructions that you have to use a new pin and remove the link when repinning or use a quick link as mentioned. I have never been in a position where this was a problem as I never have a reason to remove my chain unless I am replacing it.

fietsbob

Stimulate the economy , buy new stuff ..

nhluhr

There is nothing wrong with breaking a shimano chain as long as you put it back together correctly with the appropriate replacement pin. I use a master link on my CN-7900.

Al1943

Campagnolo recommends not reusing the plates as well as the pin. They have a kit with a few new links and a special pin for breaking and re-connecting their chains.
The only time I break a chain is to replace it. I always get at least 5000 miles out of a Shimano 9 or Campy 10 speed chain.