I am trying to make my current chain shorter, and I am wondering how I can do that. The chain is new and it is a shimano 11 speed, but I had already installed it with the quicklink (quick link is now connected) and im wondering if I can reuse the chainlink pins that I will pop out. Or, reuse the quicklink
It is not advisable to reuse a previously pushed out link pin to rejoin the chain. The chain will quickly come apart at that junction when riding. Shimano chains can be rejoined with a special, speed specific, reinforced chain link pin, which has tapered, guide aspect, followed by the reinforced link pin. When the link pin has been fully inserted into place with a chain tool, the tapered, guide pin is snapped off.
The reinforced part of the link pin features a diameter that is slightly larger than the factory link it replaces, making the fit more secure. This is also the reason Shimano advises one to break the chain at a different location than where it has previously been disconnected and rejoined with a reinforced link pin.
In my personal experience, when necessity has forced me to rejoin a bike chain with the same pin that was forced out to break it, KMC chains stayed together just fine but Shimano chains came apart at that spot very quickly. More than once during the very next ride after "repair." Thus, reusing a previously pushed out chain pin should be avoided.
Quicklinks--the Shimano branded version of the handy, special pair of outer links, known generically as a "master link," which are used to rejoin the ends of a chain, are a bit of a different story in practice. The majority of anecdotal evidence regarding the use (and re-use) of these has been favorable. It seems that failure of a reused Quicklink is so rare to non-existent that reuse is commonly practiced despite Shimano advising against their reuse in joining a chain. It has also been shown successfully, that using master links from different manufacturers, KMC, SRAM, and Wipperman, to name a few, to join Shimano chains (especially 8, 9, & 10 speed versions that Shimano advised using their reinforced connecting pins and had no master link option to offer) has become common practice. These also have excellent reliability when reused. Typically they are disconnected to allow the user better access to perform chain and drivetrain cleaning, derailleur replacement and other maintenance tasks. When taking all this into consideration, it seems reusing a Quicklink would be fine, as long as you're aware of the manufacturer's caution against this practice.
The Shimano-sanctioned ways:
- Use an 11-speed Shimano connecting pin.
- Use a new 11-speed Shimano 2-piece link.
Don't try to press a normal link back in. As there are many questions here about, the press fit isn't reliably as strong as intended, which can result in failure.
Shimano cautions against seperating and rejoining their two-piece links. While they don't elaborate on why (that I've seen), it's probably because when doing so, it can be difficult or perhaps impossible to avoid damaging the little cradle area of the link that the end of the pin rests in. If that happens, it won't be as secure. In practice this is an at-your-own-risk thing that a lot of people are doing and getting away with. Having good technique while separating them may make the difference in whether it gets damaged.
Further info, back in the old days of 5/6/7 speed chains it was quite normal and accepted practice to push a regular chain pin most of the way out, and then rejoin the chain later by flipping the chain tool and pushing that same pin back in.
Sure it got slightly malformed, but one time wasn't generally enough to hurt it, and with 100+ pins in a chain there was a low chance of hitting the same pin a second time.
As "speeds" increased, the chain gets thinner. 8 speed chain is just-about as fat as 6 speed, but 11 speed chain has an outer width of about 5.4mm and the pin has to fit flush with the outside of the outer plate. This leaves less tolerance in how far the pin goes through.
Too far through and the pin will grind on the adjacent cog, or worse could catch on an edge.
Not far enough and the side plate may pop off under load.
Upshot refitting a modern chain by reusing a standard chain pin is no longer best practice.
Your options are to use a master link (also called a quick link) in the same "speeds" as your bike, OR to use a disposable snap-off pin, which goes through the chain like normal but you snap the other end off with pliers. This is Shimano's recommended closing system, but many many riders use reusable master links without issue because its much cheaper.
The difference between modern chains (which should be joined with quick links or connecting pins) and older ones (where one could simply press out and press in the existing pin) is that newer chains have riveted pins. The riveting is integral to the chain's strength under side loads. Pressing a riveted pin out destroys the rivet, so the chain is apt to snap when heavily loaded.
Additionally, I've never had success trying to push a riveted pin back in. The mushrooming of the pin makes it very hard to drive into the side plate straight; it always wants to go in crooked. Learned this the hard way trailside.