Technical FAQ: Quick links and more pedal thread questions

Lennard Zinn answers questions about chain quick link compatibility, why pedals come unthreaded, and Di2 wireless technology.

Dear Lennard,
Yesterday on a ride, a buddy broke a chain link. I had a KMC 10-speed quick link and a tool, we both ride 10 speed Shimano, so the problem was quickly solved.

However, we got to wondering about compatibility between drivetrains (9-, 10- and 11-speed, and Shimano/Campy). In a pinch, can you use a 10-speed quick link on an 11-speed (or 9-speed) chain? And do the links work for both Campy and Shimano?
— John

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Dear John,
You can use a 10-speed master link on an 11-speed chain, because the chain is narrower than the master link. But you cannot use a 10-speed master link on a 9-speed chain, because the chain’s inner links will be wider than the inner width of the master link. You might get lucky mating one brand of 10-speed master link that happens to be a bit wider than most with another brand of 9-speed chain that happens to be a bit narrower than most. But in general, I would not expect it to work.

Yes, the links work for both Campy and Shimano chains. I raced cyclocross for many years on 10-speed Campy and Shimano chains with Wippermann 10-speed master links holding them together. Same goes for my travel bike, on which I would remove the chain every time I put it in the bike case in order to not have everything end up in a tangle.

I did discover, by breaking a master link once, that it is not a good idea to keep using the same master link when you replace your worn-out chain. I hadn’t kept track, but I’m guessing I had replaced that chain at least three times and kept using the same master link over and over. It doesn’t seem like a smart move now, but it sure was easy; hindsight is always 20/20.

If you use a master link to hold your chain together, replace it when you replace the chain.
― Lennard

More on pedal thread direction

Dear Lennard,
I understand the mechanics behind the way pedals are threaded, but I can tell you also that I’ve personally helped two riders, with perfectly good pedals, re-attach them after they came off on steep climbs. Regardless of the intent behind the pedal threading, it seems even a good pedal can generate enough friction to slowly but surely unthread, if it’s only hand tightened to start.
— Steve

Dear Steve,
I also have a buddy who came across a guy on a local trail on a brand new mountain bike from Walmart whose pedal had just fallen off.
― Lennard

Dear Lennard,
I enjoyed your ideas about pedal thread direction but I must disagree with part of your theory. It may be correct that if a bearing seized, and if the pedal weren’t tightened very well on its threads, the pedal would just unscrew rather than breaking the leg of the rider or causing a crash. However, in my long experience working on and riding bicycles, the pedal threads tend to get so tight that they are difficult to loosen even with a wrench. I propose that in 99.99% of cases, if the bearing were to seize (which is a very rare situation nowadays), the pedal would not un-thread. The rider would either have to coast or, if he happened to be on a fixie, would still be likely to crash. Pedals are so infrequently removed, and then they get tightened by the “precession” you mentioned, they are generally so tight that they could not be unscrewed by the rider’s pedaling action even if they bearing seized.

Dear Mike,
I used to think that, too, until I saw my daughter pedal off two seized Crank Brothers pedals in cyclocross races. She doesn’t live far from me, but once I help her set her bikes up for the season, she doesn’t tend to ask me to work on them, and we certainly put the pedals on tightly, and those incidents happened in two different seasons. So I’m betting that those pedals were on there very tightly until the bearings started to seize. The constant power washing of ’cross race bikes exposed the propensity of the needle bearings in that 2012ish-era Eggbeaters and Candys to seize up (current models have plastic Igus bushings, and Refresh Kits are available to replace the needle bearings with them).

My theory is that the seizing of the pedal is a progressive thing, and as it happens over time, it is gradually unscrewing the pedals. Yes, a shoe attached to a cleat could not unscrew a tight pedal with a frozen bearing. But if the bearing freezes slowly over time, I am convinced that it can. I’ve seen it happen twice when I had firsthand knowledge of the circumstances.
― Lennard

More on Di2 Bluetooth and ANT+ connectivity

Dear Lennard,
So to summarize, the three options are:

SM-EWW01: ANT+ only. Will connect to a Garmin that has ANT+. Will not connect to an iPhone, iPad, or Android device for programming. May be obsolete?

EW-WU101: ANT+ only. Will connect to a Garmin that has ANT+. Will not connect to an iPhone, iPad, or Android device for programming.

EW-WU111: ANT+ and Bluetooth. Will connect to a Garmin that has ANT+. Will also connect to an iPhone, iPad, or Android device for programming via E-Tube.

Is that correct?

Dear Ken,
You’re correct on the first and third items, but not on the second.

Both the EW-WU101 and EW-WU111 are Bluetooth and ANT compatible. They work with the e-Tube app on a phone or tablet as well as with a Garmin. They are interchangeable other than a geometry difference; the EW-WU111 is inline with a port on each end, and the EW-WU101 has both ports on the same end.

You can put a D-Fly unit anywhere in the system. The EW-WU111, with ports on either end, facilitates hiding it inside the frame (although the signal will probably be weaker). The simplest method, if it’s done as an afterthought, is to use the EW-WU101 on the lower seat stay. Just unplug the rear derailleur; you run the rear derailleur wire up from where it pops out of the end of the chain stay and plug it into one port on the EW-WU101. Then, run a short wire from the other port to the rear derailleur. The photo is of the EW-WU101 on my gravel road bike, mounted as I just described; I haven’t used the EW-WU111.

As long as you’re not using the satellite (climbing) shifter, you can instead use the SC-M9051 or SC-MT800 Bluetooth/ANT+ digital display units for XTR Di2 and XT Di2, respectively, on a road bike. The digital display only has three ports, though. If you’re using a climbing shifter, you need the 5-port Junction A, which is not a transceiver.
― Lennard