A note of caution:
Calling something a "6 speed chain" does not mean that the chain has certain dimension shared with all other 6 speed chains, it may just mean that it shifts fine on a six speed freewheel.

So if you buy a "6, 7 and 8 speed chain", that's really an 8 speed chain dimensionally. It will work great on 8, 7, 6 and 5 speed cogs of any type.

A true 6 speed chain from 1988 is much wider, and that extra width is mainly in the side plate thickness. That thickness allowed the pins to hold just from friction. When Shimano came out with their 8 speed systems, the new spacing required side plates too thin to reliably re-pin. That's why we have one-use pins and quick links.


I don't know if there are any quick links that are reliably compatible with 1980s width 6 speed chains. There might be, but since no one makes those width chains anymore and they don't need quick links or special pins - I doubt it.