Hi Snoogly!
As I recall, you have that lovely black disc-braked Carl Strong with the shop-installed Rohloff. My, it is a beauty!
You asked...
Can anyone confirm that the link on this chain can in face be re-used (on the same chain, not switched to a different chain)
<nods> Yes, I have done so repeatedly on the same chain and continue to do so with no problems. That is also the general concensus here:
http://forums.mtbr.com/drivetrain-shifters-derailleurs-cranks/re-use-kmc-missing-link-whats-your-advice-670607.htmlYou also asked...
does one have to use a tool to remove it?
No, no tools needed. It is a simple thing to remove, but as with other connecting links of this type, there is a small trick that isn't obvious that will make it go so much easier: Be sure to pinch the links together as you slide them apart. <-- That's the trick: Pinch, then slide. Sometimes, you'll even hear a little "click" as you press the links (press the sides directly *in* toward each other). Once you've done that, just slide the link halves lengthwise relative to each other, and the plates will release, allowing the mating halves to come apart.
Re-installation is the reverse of this process. I put one connector-link half in each chain end, align the pins with the holes, pinch together and then slide my fingers (and with them, the two link-halves).
As the chain wears, so will the link, becoming a bit easier to remove and reinstall. I have never found a connecting link to release accidentally. I believe it was Pavel who voiced the very good idea to install a *couple* connecting links on his chain so he could easily remove a link-pair on-tour when his chain stretched beyond the remaining take-up afforded by his eccentric bottom bracket. I have seen chains comprised of discarded excess segments joined by a number of connecting links, and I believe Dave Fife has seen similar in his regular shop-repair experience. I've never seen a link fail outright, though I suppose it could happen.
I hope this helps. If you have any trouble installing or removing the connecting link (sometimes people do, till they get the hang of it), give a shout and I'll put up a little photo-illustrated tutorial.
Regarding your last question...
is it possible/advisable to substitute one of the missinglinks that is claimed to be resuasble?
...Again, yes! I have had excellent results substituting other manufacturers' links so long as the link is the same width (same number of "speeds") as the chain it is used on (i.e. 9-speed link on a 9-speed chain). The KMC Missing Link is reusable in my own experience, and I have also substituted a SRAM link and found no increase in noise or skipping or problems in mating so long as they were all the same dimension and also the same age/wear. I had the same good results using a KMC link on a SRAM chain and a SRAM link on a Shimano chain. Once installed with the new chain, I kept the same link with that chain for the life of the chain, discarding it when I discarded the chain. I start out with a new link on each new chain.
I do believe it is wise to replace the connecting link every time you replace the chain, as it is another link and will wear at the same rate as the others.
Best,
Dan.