Shimano Synchro for Triathlon

I’ve been riding around on a couple of Shimano’s technologies and thought I’d report in. You should at least be aware of Shimano's 1-button shifting and it's Synchro shifting. While Synchro is an option for standard road control units it’s really the only way to ride 1-button tri/tt shifting (unless you’re running electronic 1x which is technically—but I don’t think officially—possible).

I threw up a little 20sec video of the shifting at work while the bike is on the stand (below). But first things first. And, can I say in advance, there’s a lot I’m leaving out. This is meant for those who want a quick and dirty look at this classy system.

What’s caused me to migrate to 1-button shifting? Basically, after all these years, I still don’t know, in the heat of battle, for certain, which button does what. Now, I’m a regular Jose Feliciano on any sort of mechanical shifting. I'm dead fluent in everything mechanical, which paddle, which direction, without looking, SRAM, Campy or Shimano, road or tri. But two buttons on one shifter stupify me. I know intellectually which does what. But when I’m doing my slow version of drilling it, and my IQ falls to 70, my brain stem needs to know which button does what, and it doesn't.

This is why the 1-button system (for either SRAM or Shimano, but Shimano in this case) appeals to me. The way I have mine set up, the right hand shifter pushes the chain to the right, and the left hand shifter to the left. The “right” in this case always means a bigger gear. The cog to the right side of the bike. The cog toward the outside, away from the bike. That’s always a “bigger” gear, i.e., harder to pedal, you go faster per the same number of pedal revolutions. That’s how I remember it: push the right hand button, the chain moves to the right; push the button on the left extension, the chain moves to the left. Same thing with the shifters on the pursuit bars. This is my tri bike version of righty-tighty, lefty-loosy.

But we’re adding one more wrinkle to this, which is that Synchro shifting means the “system” decides when the front derailleur should shift.

This isn’t necessarily sequential shifting. Technically if you were looking for the next larger gear on your bike (or the next smaller) your front derailleur would be shifting an awful lot, because out of the 22 available gears on your bike, there would be a gear between 52x19 and 52x21, maybe 36x14 or something. But the bike is not always going to be hunting for that exact in-between gear. Let’s take my bike as currently set up, for example.

I’m riding a Diamondback Andean with Shimano Dura Ace Di2 9150, Rotor crankset, PremierBike chain. Why did I choose this equipment? Because the Andean is my test mule, and I’m constantly putting stuff on and taking it off. This just happens to be what’s currently on it.

What I’ve got on that bike is 52x36 on the front and 11-25 on back. The Shimano system has decided that it likes 52x23. If I’m in, say, 52x15 and I’m starting to climb a very slight hill that’s getting progressively steeper, I’ll shift the left button (easier gear) and the system will shift to the 16t cog, the 17t, and so on until the 23t cog (the second to the inside). Then when I hit that left hand button one more time the front derailleur will drop the chain to the 36t ring and the RD will downshift twice, to the 19t cog. That’s the next lower gear.

You might think that if I now shifted in the other direction, to the next larger gear, the reverse would happen, and the FD would again shift, but no. in fact, I get 3 more shifts into larger gears with the chain on the small ring before the system decides I need to be in the big chain ring. This is to keep the FD from constantly shifting. I like that.

Of course, the system also performs the very best electronic function: the FD auto-trims. The very best thing about electronic shifting is FD function: auto-trim and absolutely zero chain derailings. Hey! To everyone who posts on our Reader Forum asking whether ruined frames due to chain suck is a warranty issue! Most of this frame damage is due to the chain derailing, and electronic shifting eliminates that.

To be clear, this system isn’t faster than mechanical. In fact, it’s slightly slower, in terms of shifting speed (much more reliable and trouble free! just, not faster). It completes the FD shift before it commences the RD shift. And, it doesn’t perform both rear shifts at once. There are 3 distinct shifts the electronic system performs: FD, then RD downshift, then a second RD downshift. If you watch the video this all happens at 9sec into the video. It’s not a big deal. Just, it’s not dope (as the kids now say).

And, look, there’s an inexorable march toward certain technologies, and you can complain to me and I’ll make sure it goes into the right file. We’re heading toward disc brakes and electronic shifting (and maybe tubeless tires). Electronic is kind of like using smart phones; it’s easy if you grow up with it; less so if you learn it late.

Let me see if I can demystify a couple of things. The E-Tube System is simply Shimano's software that allows you to set up, adjust, customize your shifting. It works nicely on a Windows machine. There’s a way to Bluetooth into the E-Tube system from your bike but, really, no need.

There’s a couple of options for the set up. One is, if you want to charge your battery without taking it off the bike, there’s a charging wire you can plug right into your Shimano electronic 5-port junction box. This charger bears the name BCR2. One end has a USB port, if you plug that into your computer that hosts the E-Tube software, that software can pick up the signal from your bike through your charger, and you can configure electronic shifting that way.

But this isn’t what the BCR2 was built for; it’s primarily a charger. I don’t get the sense Shimano wants your bike to use that to talk to your computer. There’s another interface device called a PCE1, and it’s real job is to talk to the E-Tube software. I’ve used both the BCR2 and the PCE1 to connect my bike to the software and the PCE1 is slightly more reliable. Sometimes the BCR2 just doesn’t want to talk. So, the PCE1 is more communicative.

The PCE1 comes with 2 ports (I don’t know why, you only need 1); and it comes with a wire for each port, which is fine but you only need 1. What you do is, you pull one wire out of your bike's 5-port junction box (pull out one of the wires that goes to one of your pursuit shifters; that works nicely) and stick in the wire from the PCE1 interface. Then you’re ready to do whatever kind of programming you want. The only programming you can’t do using this method is something I had to do: for some reason my left and right pursuit shifters were backward (remember, the right shifter should shift to the right, the left to the left). I had to “tell” the pursuit shifters to shift opposite of how they were set up. This was easy to do, you just can’t do it unless both those shifters are plugged into the 5-port hub.

Speaking of dope, there is the dope set up for this. On any Shimano Di2-outfitted tri bike you have 2 junction boxes: a 5-port front junction (if you have electronic pursuit shifters) and a 4-port junction down on the bowels of your bike. Into the 5-port go the 4 shifting wires (2 pursuit and 2 bar-end) and then the 5th wire travels back to the ship’s bilge. Down there is the 4-port B Junction Box, into which the wire goes from the front junction to the bilge. The other 3 ports are used for your battery, your FD and your RD.

But you can put another B Junction Box anywhere you want in the bike. As many as you want, in fact. I’m going to get myself another one and put it right next to my front 5-port junction. It’ll act like a splitter. I’ll plug it inline between my 5-port junction and my B junction, and then I’ll have 2 more ports available. One port I’ll keep a rubber plugged in so that water doesn't get into it, the other will be what I plug my PCE1 wire into whenever I’m updating firmware or fiddling with the on-board system.

The screenshots sprinkled herein are just a couple you'll see when updating, adjusting, customizing your shift system in Shimano's E-Tube software.

All this is pretty easy to work. I’m not the smartest tool in the shed, especially when it comes to new-age electronicky stuff like this. But it’s all fairly intuitive, and it’s quite plug-and-play. What I like best is not having to worry about shifting and, especially, about front derailleur function. I suspect the most frequent catastrophic bad equipment luck that befalls triathletes, outside of crashing or driving your loaded roof rack into your garage, is chain suck and chain wrap that pulls RDs out of their hangers, and hangers out of their dropouts, due to derailings. Electronic shifting is so good at stopping that, SRAM has made its own chain catchers obsolete (unless you’re riding mechanical).

So, basically, lefty-uppy, righty-downy. That’s 1-button/Synchro from Shimano. The part of this system you need the least is pursuit shifting, if you’re on a budget. Yes, there are new little weirdnesses, like the 23mm cone wrench you need to tighten the wedge mechanism for the 1-button bar-end shifter (you have this tool, right?). Otherwise, there’s only 1 word to describe Shimano 1-button Synchro: Dope.