Mechanic vs Di2 Maintenance
 

I have three drop bar bikes, all with mechanical shifting (one with friction shifting). With my racing bike, I've been frustrated by the amount of maintenance I've been having to do on it. Sometimes, it has been with the barrel adjuster being off. Just as often, it seems like the derailleur hanger bends a lot, even though I always replace them after they bend (this is not an issue with my other bikes). This has made me consider replacing my racing bike with a bike with Di2. IF I get a bike with Di2, I'd prefer Ultegra Di2 with rim brakes. I know people feel strongly about electronic or mechanical one way or another. I'm open-minded, and keeping my maintenance to a minimum is my biggest issue. I have a few questions:

• Would I be performing less maintenance/making less trips to the LBS with electronic shifting? Or, would I just be replacing one problem with another?
• How does Di2 perform with a mildly bent derailleur hanger? Does it also suck? If not, will it just get more bent over time if it isn't straightened?
• Is it possible that the biggest culprit of my shifting issues on my racing bike is the combination of the frame and derailleur hanger? This wasn't nearly as big of an issue with my previous racing bike, and my other two drop bar bikes are both chromoly, so their derailleur hangers are integrated.

I have never bent a mech hanger. What are you doing to them?

Di2 wouldn’t like it either but eliminates cable issues

There's an underlaying problem if you are constantly bending derailer hangers. I have bent a hanger maybe twice in 35 years and had a shop fix it.

Moving to Di2 is not going to solve your bent hanger issues, as Di2 is every bit as sensitive and possibly harder to accommodate a bent hanger, the way you do with a mechanical by over compensating with cable tension.

As Choddo stated, Di2 does eliminate the need to replace cable and housing, but you still need to replace the cassette and chain every few years when they wear out.

Ditto, Di2 is as sensitive to a bent hanger as mechanical. I don't think it is worse though. You can still electronically adjust the derailleur in or out like you would with mechanical. While technically possible, Shimano has NOT designed the Di2 systems to give you individual gear position adjustment. Just like mechanical cable adjustment, the single Di2 adjustment affects all gear positions.

I also wonder why you are bending hangers so much. I assume something to do with transporting the bike.

In general, a Di2 system will need less adjustment than mechanical. Di2 is sort of set and forget. There's no cable to stretch or get dirty, or barrel adjuster that can move. I have Ultegra Di2 on a bike I bought last July, so about 6 months of use, and once I got it set, I've not had to touch it since then and have about 2,500 miles.

Di2 won't help with those problems. And I'll add to the chorus of posters asking what are you doing to all of those derailleur hangers? Are you crashing (and landing on the drive side) that much?

If bent hangers are a common problem, consider swapping the hanger for one made by Wheels Manufacturing, they tend to be a bit stiffer than the average stock hanger that comes on a bike.

Over the years, I've had a number of different bikes. On some bikes, the derailleur hangers rarely bent. On one bike I had, it seemed to bend, often badly, after every three rides. I probably went through 10 derailleur hangers before selling the bike because of all of the issues I was having with that derailleur hanger.

As for this bike, I've probably went through 3 derailleur hangers in a span of 2 years. I did switch to Wheels Manufacturing derailleur hanger. On this bike, the derailleur hanger doesn't bend too badly, definitely not as bad as the bike I mentioned above. For that reason, it is sometimes hard for me to tell if the cause of the subpar shifting is because of the tension or the bent derailleur hanger (but my LBS can tell). I don't lean or drop this bike on the drive-side any more than on my other bikes (I never intentionally do this with any of my bikes). Is it possible that the design of the derailleur hanger for this particular frame is weaker than the derailleur hangers for my other bikes?

In any case, thanks for letting me know that Di2 wouldn't solve this particular problem.

Derailer hangers do not spontaneously bend, since they are not actually under load. They only bend under impact or some other catastrophic event.

I suspect you are having some other problems… But I have no idea what could be going on.

As Koyote noted derailleur hangers don't just bend. I would suggest figuring out why they are getting bent so often. It could be as simple as you laying your bike in the back of a vehicle on the drive side or leaning on the drive side elsewhere or you are really crashing a lot or something like that. We probably won't know what actually happens though.

In the case of mechanical vs. Di2 I would say Di2 is pretty low maintenance and with the new Di2 it is super easy to adjust without a tool just using a phone. It is really a ton of fun and way better than SRAM AXS which only allows you to adjust all the gears at once vs each individual on Shimano. With electronic shifting there are no cables to adjust or fray. However in the end a good quality derailleur and proper initial adjustment will generally lead to fewer issues to no issues.

Though truth be told Di2 vs. mechanical is not going to change much if you are damaging your hanger like that often.

Maybe start with a new bike that has a UDH standard and get a T-type AXS setup. I bet after that, all your hanger and shifting problems will go away.

On the bike(s) where the RD hanger(s) bend(s) for no apparent reason, is/are the chain(s) too short for big/big?

I have also been studying Di2 in consideration of an upgrade, but as far as I can tell the only advantages are (1) faster shifts (meh) and (2) not having to replace shift cables every 2 years or so. My theory is that since Di2 now comes with 12 speeds and (potentially) closer cog spacer, a bent RD hanger would affect shifting even more prominently than on a 11-speed mechanic drivetrain.

A bent hanger had NOTHING to to with the quality of your derailleur system.

Before spending a penny on upgrades or changes, find out how and why the hanger is bending and fix that.

it’s also just a different experience. a tap of a button instead of pushing the whole lever over. no lateral lever movement at all when braking. at least compared to my GRX bike, it’s night and day. faster, more reliable (for the maintenance reasons you note), more satisfying, more flexible (make whatever button do whatever you want,) easier to adjust. as for the spacing… 10,000+ 12 speed di2 miles and I have literally never had to adjust anything, and while it’s possible the derailleur hanger is in the exact same position as it was, it seems more likely that it’s some tiny amount off from accumulated abuse and in fact the system is no less forgiving than 11 mechanical speeds.

i would never buy a mechanical shift bike again, but that’s just me!

That was my first thought about someone that seems to bend the hanger on a somewhat regular basis.

The reason for why you are bending the hanger is independent of the level of maint required for Di2. I have an 11-speed Di2 on my bike and other than 1-2 times during the riding season (I live in the Boston area), the only maint I perform is to recharge the Di2 battery. While I have no need to make adjustments on how the Di2 system operates, you can adjust, configure and play with it as much as you want via the etube app which communicates to Di2 via Bluetooth.

Caveat: My Di2 is 11 speed. But I don't find the shifting any faster than a good mechanical system -- in fact, with my shift speed set to four (on a five point scale) it is a little slower than a good mechanical system. (I've been told that setting the shift speed to five raises the odds of buggering it up.) It's especially noticeable when shifting both derailleurs at the same time, as when starting a hill or cresting one -- it seems like the system shifts one derailleur, then the other. With a mech system, it's easy to push both levers at once and execute simultaneous shifting.

Never having to worry about shift cables is great, especially since 11sp Shimano is known for shredding cables inside the shifters.

Another unanticipated benefit is that Di2 can connect via bluetooth to a cycling computer, which can be programmed to show your current gear combo on the display -- it's great when climbing in rough terrain (gravel or mtb) and I want to know if I still have a bailout gear without looking at my rear wheel. Also, I've got my shifters' top (auxillliary) buttons can be programmed to scroll through the display screens -- or with a long press they turn my taillight on or off. Surprisingly useful.

I have mechanical Ultegra and other than replacing cables every year or so, not much maintenance.

My friends with Di2 or SRAM electric seem to always be taking their bikes to the shop for something.

That said, I certainly would buy electric next time, just like a car, but new-and-improved doesn't necessarily mean less maintenance.

Maybe you need to put kickstands on your bikes so they won't fall over.

I switched from 11 speed Ultegra to 12 speed 105 Di2 around 18 months ago and love my Di2. It is nearly maintenance free...which I actually complain about...No more checking the adjustment of the derailleurs for cable stretch...or whatever you want to call it.
I also use submersive waxing for my chain so even less maintenance as I'm not using agents to degrease my chain, remove the degreaser, lube the chain, let it soak in then wipe off the excess. Now I just replace the chain with a freshly waxed one every two or three weeks. Yes I do have to clean the 'used' chains but I wait until I've used the last good chain...I have three in rotation...then I do them all at once. I always measure the wear on the old chain when replacing it.

I had no problems with the mechanical Ultegra 11 speed system except I found that shifting the front derailleur took more force than I expected...I went from the long arm version to the latest because Shimano said it took less force to shift but I found the difference barely noticeable. No matter how I finagled it took more force than I expected...I have small hands and shortish fingers which is the likely reason.
The rear derailleur was perfect.

I have the 12 speed Di2 set up for the fastest shifting mode and it is amazing. What I really like is the internals are the same across the board...Dura Ace, Ultegra use the same internals, just the externals are changed. Oh and the front derailleur is the 'old' style Dura Ace, not the sleeker brain new version but that is fine as I generally don't look down at the shifter while riding.

Regarding rear mech hangers...I have found some to be much less robust and reliable than others. It depends on the maker. Some are so cut out that I've wondered if they may flex and/or bend under heavy load shifting...trying to shift to an easier gear while in the big ring and climbing a steep grade while out of the saddle is one example. That is a lot of load.
My 'wondering' is based on over 30 years in the bike biz working at several shops as a salesperson, builder, wrench monkey and service manager...all the way from 5 speed down tube friction bikes to today's...including recent builds of a SWorks SL8 with a full Dura Ace 12 speed groupo and an Aethos with 12 speed Ultegra as well as building my Aethos with 12 speed 105.

My only caveats is the potential for failure in electronic systems. It is there and should be considered. Electronics can fail and usually do because of the manufacturing defect...if this defects pops up during the warranty period, woohoo it is covered but if it doesn't until the warranty is expired you are SOL.
Mechanical systems generally don't fail...the mechs, brakes, etc...they can last decades even with abuse and still work fine once serviced.
If an electronic part fails it fails...it is dead, done and you have to replace it. Fortunately it doesn't happen often but it does as is validated by some of the posts on this site offered by people affected. And at the replacement cost it is something to be considered...this sh i t isn't cheap lol.

Going back to maintenance. As I said I usually replace my chain maybe every two to three weeks, sometimes going for a full month at this time of year as my bike is on a smart trainer for the winter. During 'road' season I replace the chain every two weeks or sooner if caught in the rain or I did a ride/event/race that had sandy roads and my bike had a coating of dust, etc. on it after the event. Back to the trainer...I put the bike on my stand, check the chain wear with a Park tool, replace the chain and give the bike a good wipe down with either Bike Lust or something similar...I have a couple of different products I use but none of them stand out as "oh my goodness this is amazing"...they just work. I generally seldom check the rear mech hanger, the Aethos hanger is pretty robust but I do have six spare hangers...oops I clicked twice when ordering and only wanted three lol...I did bend one once when my bike fell over, of course onto the drive side. It was only on grass but is did bend enough to cause the shifting to be wonky and even adjusting the cable tension did not fix it completely. When I checked it at home it had a decent bend to it...this was using the Ultegra mech system.

Wow, I did not intend this to be so long but there you have it. I'm done now. Ride on !

On my bikes, I use the "big-big" method to size the chains. I double-checked the chain length on my road bike. There are 2 extra links on my road bike. I am skeptical that the chain is too short. I don't think that this is likely, but is there any possibility that the combination of a relatively large cassette in the back (11-32) and the aggressive geometry of my bike has anything to do with the derailleur hanger bending?

I was unaware that you could change the Di2 shifting speed. Is that done thru the ETube app?

Bending hangers could be from how you transport the bike. Particularly if more than one bike is involved. If you have kids, don't underestimate what those little angels are capable of when out of sight. They might be climbing up to get to something behind where the bike is kept and stepping on the RD sometimes.

Yes.

I'm definitely interested in the UDH standard, but why would it matter if I get AXS over Di2?

Found it....thanks!