Di2 Cross-chain Limiter stopped working
 

I'm new to Di2, been riding with it for about three months. When I first got my bike the system would prevent me from cross-chaining and recently I've noticed it no longer does that.

Any ideas on how to fix that? Is it more likely to be hardware or software?

Software.

Something got changed.

Mine works that way by default. I've avoided doing firmware updates due to the fear that cross-chain prohibition would be forced upon me.

Have you modified anything in the software ?. Maybe you activated one of the Synchro modes ?,

Typically the lockout on the 2 lowest cassettes is dependent upon what crank and cassette the system thinks you are using, with only a select few combos allowing the system to shift small/small or small/next smallest, as well as being in other than Synchro mode.

I'm not aware of any config changes I would have made but it's possible I did so inadvertently. Documentation for eTube isn't great and I've looked for help. Can you point me to which setting I should be looking for?

Before you start diving into e-Tube, I think we need more information on how you shift. There are a lot of different ways to shift in Di2, and the "shift mode" you're in heavily influences both how you shift and your expectations on how the drivetrain should behave during shifts (because Di2 will do certain things automatically for you in some modes). So, if you aren't sure what the three shift modes are on Di2 then you should try to read up on that first, so that we can understand exactly what you were doing before and what changed now.

For example, if you normally shift by ONLY pressing the up/down paddles on the right lever, and then let Di2 shift the front chainring automatically, then you're probably have been using full-synchro mode. In that case, if you accidentally switched to manual mode, then I believe it will remove the cross chain protection at least in the big-big direction, but I think it still locks out at least small-small if not more.

So, while it doesn't entirely explain the behavior you're seeing, it's not impossible to have changed the shift mode accidentally by inadvertently double-pressing the button on the A-junction box. I'm pretty sure I've done it a few times myself while fiddling with the button to get into either adjustment mode or Bluetooth pairing mode.

Once you understand shift modes, the next step would be to figure out what mode you think you should be in based on how you've been shifting up to now, then go read out what mode Di2 is currently in on your bike (there's an easy procedure for this which doesn't require e-Tube).

You sure you didn't accidently change the shift mode by double pressing the junction box button? Work computer is preventing me from copying and pasting links, so do a search for "changing Di2 shift mode". You should be able to pull up something that explains how it's done.

Edit: Metaluna has already suggested the same above.

This looks like a pretty decent summary of how it works. Probably more readable than anything from a Shimano manual anyway.

https://www.bikeexchange.com/blog/sh...ings-explained


One possibility is that up to now the OP has been in one of the synchro modes, but thought it was manual mode. Both synchro modes allow you to shift the front an rear manually to a degree. It's only when you hit certain shift points that Di2 will take over and do some shifts that you didn't ask for. But a naive user might just chalk that up to the "cross chain limiter" doing it's thing. Take full synchro for example. Unlike semi-synchro, you can shift the front and it won't try to shift the cassette at all (even if it takes you off the progression in the shift map, IIRC), so there's nothing to tip you off that you aren't in manual mode. So you can go along in full synchro, happily shifting the front and rear yourself, thinking you're in manual mode. Except sometimes, when running up and down the cassette in your "manual" mode, you notice that it shifts the front for you. Oh, that must just be the "cross chain limiter" kicking in. But it's really the synchro mode following its shift maps, which happen to not allow big-big or small-small cross chaining, among other things (by default anyway). Then you double click the A junction button by accident, and that flips you from full-synchro back around to Manual. Suddenly the "cross chain limiter" doesn't work at all, or at least not quite the same way it used to.

But as far as I know, none of the modes, even manual, ever allow small-small cross chaining with the latest firmware, and there's no way to turn it off, so if the OP is truly able to shift into small-small, something else must be wrong.