[QUOTE 4864356, member: 9609"]I use the tool to take the chain off about every week and I ain't damaged one yet, I love the system really quick, even after many repeats the link seems to make a nice click when put back together.
(7 speed chain)[/QUOTE]
I agree that damage doesn't seem evident, but then again, few people have a good look. There is some plastic deformormation in those notches. I also agree that with repeated use you can still generate a nice click, but certainly not one as strong as the first one. It's all moot, if it still works.
I don't suggest wide-scale failure but I have had one experience, and only one, where a quick link did undo itself and the chain came off. With the double safety system of a recessed key slot and a narrow press-fit passage for the pin to move through, the already slim chances of a link coming undone are double. Double a slim chance is nevertheless still slim. Unfortunately I never took the trouble of examining the link closely afterwards and I can still kick myself for it.
For this to happen - the link to come undone - the specific link out of the 100 or so on the bike, has to be at the right place at the wrong time. We know the chain cannot be in tension for it to happen, thus it has to happen somewhere in the slack run. We also know that the link has to pushed together whilst the chain is slack and, I would imagine we need some vibration and a dry-ish chain to make it all the more plausible. These conditions are of course rare: the shifting link has to be under sideways compression (which only happens at the rear sprocket somewhere between half-past and 12 'o clock, without tension in the chain (no pedalling, possibly with a dodgy freehub body that keeps on turning when you stop pedalling, a bumpy road and dusty or wet conditions which would have dried out the lubrication.
It seems to me that the odds are so small that had I played the Lotto that day I'd be typing on a gold-plated keyboard right now.
However, would you mind, next time you change your chain and prepare to dump the much-used link, to let me know. I'd like you to send it to me and I'll examine and photograph it.
