Put me in the camp of liking the current fully wired Di2 setup. I don’t get why people dislike this. It’s not like you are setting it up multiple times. Yes if takes more time to set it up the first time compared to SRAM, but after that the single, longer lasting battery is awesome
The exposure does not seem to be a problem, even in rougher environments (their MTB groupsets use the same battery).
In practice, it seems to be equivocal: Di2 has a longer-lasting battery, but it is harder to charge. With eTap batteries, you can always bring a spare with you. (One former team mate’s Di2 battery ran dry the day of a race even though he had charged it the night before. He fortunately found someone who brought the cable.)
There are some pretty obvious drawbacks. Ever wonder why there is no Shimano 12-speed Di2 mountain bike groupset? (I know DuraAce is a road groupset, but SRAM can use developments for eTap for both, dropbar (= road and gravel) and mountain bike groupsets. Here are a few more:
- The battery is hard to access. Long battery life conversely means that you might forget to charge it as you rarely have to. (How accurate is the battery gauge for a Di2 battery? Honest question.)
- You cannot replace the battery on a ride in case something goes wrong.
- You cannot share technologies with mountain bike groupsets. Dropper posts, rear suspension and more varied frame geometries make placing a Di2 battery much harder.
The last point will force Shimano to take one of three options:
- Abandon plans for electronic shifting for mountain bikes. (Very unlikely, me thinks.)
- Develop a custom solution for mountain bikes. (Unlikely, IMHO.)
- Go wireless. (The most likely scenario.)
This. I cycle my two eTap batteries (I have a 1x setup) so that both are always charged. It is simply peace of mind, and I know I am never left stranded in one gear.
It’s a problem to my eyeballs.
Yep, my thoughts exactly
I have had a sram battery die on a ride (why no battery warning at say 50% and 25% sram?). Swap front to back and keep going. I have had friends with Di2 have their batteries die. They get stuck in the small ring and have to spin spin spin home (maybe there’s a way to change this?). Oof.
How long will di2 batteries last and how much are they to change?
That said… I’m very close to pulling the trigger on a di2 bike. Pros and cons. Both systems are fine.
I’ve been a Shimano fan boy forever but I think my next bike will be SRAM. It just seems better in nearly every way, especially for offroad riding.
I get your arguments about aesthetics, but I do think it’s far easier to just take off a SRAM battery and bring it to the charger than to try to find a place with the space and a wire long enough to charge a DI2 battery and angle everything where you can see the light to know when charging is complete. Plus, I hate their weird connection.
I charge mine maybe every 750 miles or so? I’ve never actually thought about it. I just charge them every month or two when it occurs to me.
It’s easier because I don’t have to find a place in my house to put my dirty bike that it and the charger won’t get in the way and I don’t find it difficult to unclip a battery from a derailleur.
Tell me how a single cable is harder to charge than a dock and 2 batteries
I just want to add my input to this conversation. I recently went to a SRAM AXS setup from Di2 (I had Di2 for 4-years I think) - the change to AXS is due to my bike becoming totaled and I figured I would give AXS a try.
I must say since I have had AXS on my bike for only 6-months, in that 6-months time I have had the battery die twice on me during a ride and I think I have forgot to grab the RD battery off the charger maybe 6-7 times now and had to walk back up my driveway (I live on a slight downhill).
When I am in the zone to get ready for a ride, I just grab my bike and go and if the battery is sitting on the charger I might overlook it (I am crazy time limited). I have started charging the battery’s every 2-3 days because the battery’s are such short life in my experience and its honestly not something I want to remember.
That being said, I think the AXS has inferior shifting (it just clunky and slow) in comparison to the 11-spd Di2 and the ergonomics are not comfortable to me. I have a spare bike that is Ultegra Mechanical Disc and it honestly is so much smoother and quieter than the AXS and feel more comfortable in my hand. The other thing is in all the years of having the Di2 it only died on me (1) time while riding. The system would notify my Garmin every couple months that the battery is getting low and I would hook a charging cable to it as soon as I got home and then forget about it for months.
That being said, I think AXS has some pretty cool gearing options and I was excited to try them out. I have (2) 1x bikes now and after playing with 1x gearing for a few years now I have settled on the fact that for me 52/36 x 11-30 truly is the best gearing for me on a road bike. I tried to get along with a 50 x 10-33 but to me it was not for me.
That being said, I cant wait to try out the new 13-speed Shimano and maybe its going to be clunky and slow like the 12-speed AXS 
AXS RD batteries last around 60h ride time (per SRAM). Depends on how much you shift obviously. They warn you of a low battery with ~5h left; if you pair the shifter to your head you get a warning there. An obvious advantage is if you have a dead/low battery for whatever reason it takes a moment to swap in a fresh battery pre- or even mid-ride. This is generally hypothetical in my experience, I’ve never actually had a SRAM battery get low enough to not shift.
I think this debate is largely academic, as Shimano will almost certainly go to full wireless in the next iteration of their groups. On the MTB side they’ve so completely missed the boat on wireless shifting that few frames support easy battery placement and wire routing, so if they want to have any play in that market they have to go wireless. And I’m sure road frame designers would love to quit having to design around those elements as well.
You’re killing the battery life by leaving it in the charger and by charging it far too frequently. Charge it, put it back on your bike. Problem solved.
Better still, get a spare battery. Connect your RD to your head unit. Ride till you get a “low battery” alert on the head unit. (On Wahoo you helpfully get a reminder when you end your ride, not just a mid-ride notification.) When that happens, at the end of your ride swap on a fresh battery and charge the other. Your bike is always ready to go, nothing to forget.
I’m really not sure what the pro of wireless is for shifting - cable routing is a one time job and wireless just adds risk into the mix seemingly without major benefit.
I’ve got one that is 8 years old and has done maybe 50,000 miles and it’s still going strong. As in, I still get ~1000 miles of riding between charges. So not really an issue worth worrying about IME.
For me, the the ease of the micro adjust and you can pair road shifters with MTB rear derailleurs and cassettes.
Really? Unless AXS is using NiCd batteries or not using smart charging protection circuits for Li-ion leaving a battery plugged in should not be an issue.
I have seen a case (see story above with my former team mate) where that can go wrong (where the battery either did not charge correctly or discharged over night). Does that happen frequently? No. But neither does that happen with Etsy batteries.
Provided you have that proprietary charging cable with you. If you are at home, cool. If you are out and about, that might be an issue.
Doesn’t sound good to be honest. We should get percentages like we get with smartphones or my head unit. The same goes for SRAM, obviously.
Personal preference as in Shimano vs. SRAM or central battery vs. wireless? In many discussions on this topic I feel people start from the former and go backwards.
In the big picture, I’m certain Shimano will go wireless, because they have to. At least on the MTB side. And then the question is whether it makes sense for road group sets to stay wired. This is especially important since mullet group sets have become popular and Shimano has no (up-to-date) offering. Not sure if their M9000-series XTR Di2 groupset is still on sale and compatible with 12-speed road shifters.
Many weeks with regular use (4–5 times a week, mostly on the trainer in resistance mode). I should keep notes. The spare battery simplifies my life, because once I see a battery warning, I pop in my fresh spare, put the nearly empty one on the charger and it is usually completely charged once I am back.
I charge mine maybe once a month? It’s honestly not frequent enough for me to think of it as a bother. I just click the shifters friday nights and see if the light is green. My only issues is, for example, last week when the lights were green, then when I get to the start of a 5+ hour ride on saturday morning I got a “battery critical” warning. Really? Where is the “battery low” warning? We have phones and head units. It should be easier to track battery status.
Removing and popping batteries on the charger is easier than charging my lights and about the same as charging my head unit (which I need to do more frequently than my sram batteries anyway). I already have usb cables lying around to charge all sorts of things. I’m not super thrilled with the idea of a proprietary cable for my bike (can’t you just make that USB-c too, shimano?). And I sure would like to be able to set the bike to be stuck in the big ring rather than the small if worst comes to worst and I have a long flat ride home.
But I do think I’ll pull the trigger on a Di2 sooner than latter. I’m worried about wireless batteries that are not interchangeable being the worst of both worlds.