s-works frames generally do, even the crux. as for the pro and below...i don't think so.

all framesets *should* include those adapters. if you find you need them, ping me--i have 4 or 5 sets.

-not sarcasm-

Can someone explain to me why shifting is "better" under load with electronic than cables? Why does the source of the action (cable vs. servo) matter if the actual action (derailleur cage moving) is the same?

Everyone says it, so either is mass preference justification, or it's true, but if there's a hard reason that the mechanical action is actually different, that would definitely explain why it's better.

Thanks...I've had the meter for a few months now and it seems to be working well (even in the one rainy day I put it through). The zero offset is temperature sensitive and I've checked the offset values often enough where I can usually guess the temperature based on the offset value (within a few degrees).

Slope test is done by hanging a known weight off the crank while in the 3 o'clock position?

are you talking about the shims or the actual adaptive BB like praxis or mfg? I personally think the adaptive BB is better, but I have no scientific justification for it. The bike I'm building has kcnc, which is one of those with threaded connects and uses the same shimano BB tool.

shift force
shift speed
auto trim

At the rear I can't tell the difference. Shifting on a cassette depends mainly on the cog profile - the chain waits until the ramp comes by, mechanical or electrical. The derailleur geometry, the cog profile, that makes more of a difference than what actuates the mechanism. Since I primarily shift in the rear only I can't justify the price of electronic (nor the associated stuff related to the fact that all my stuff is Campy 10s).

The electronic front… it totally blew my mind how well the first gen di2 worked (I haven't shifted a later version or Ultegra). I was on a trainer, so real bad slow spots, pedaling at 20 or so rpm under load, no easing like I do normally (I had to do a few shifts before I got rid of that long ingrained habit), and it shifted the chain into the big ring with no problems. No way I could do that with a mechanical. Lots of noise, fine, but it shifted. I wouldn't shift like that but it illustrated just how well it would work if you were desperate and just shifted with no regard to the health of your drivetrain.

Maybe a merciless rider with super strong fingers could shift a mechanical similarly but I certainly can't. With the same cranks, chain (but different front derailleur, not sure of geometry or cage differences), the mechanical equivalent would flub shifts all the time.

For me the shifting performance is such that I'd consider regularly shifting into the small ring in a crit. Generally speaking I don't shift out of the big ring. I'd say I drop my chain maybe once every few years but that's too much risk for me. With electronic I figure that would go to zero.

thx dudes.

I think I am so used to the moment of shifting that I no longer think about it. Anyway, everyone seems to like it and it's unlikely you're all wrong.

I would argue precision. I mean how much more leverage can a small motor have than your hands on a long lever? for a mechanical setup, on an upshift, you're pretty much relying on your high limiting screw to stop you from dropping the chain. on an electronic shifter, it knows exactly how much to move the derailleur to make it shift just right.

Do you own Di2?

no, but I kind of want to block the FD from shifting on an electronic group to try to prove my point.

confirmed on Closer look: Shimano Dura-Ace Di2 transmission | Cyclingnews.com

shift speed on di2 is actually slower than on a mechanical system. a derailleur's shift speed is limited by the chain's contact time against the sprocket/chainring, not by the movement speed on the derailleur. the advantage for di2 is that its motor moves in a controlled manner, and overshoots the shift slightly to make the transition easier, and this happens in both directions. you can't replicate this very precisely on a mechanical system, and when you tap the small lever, the release in tension is not a controlled movement, but rather just a drop, and there is no automatic overshift.

Thats a really old article based on 7970 introduction. Much has been improved since then.

Other features of Di2 include multiple satellite shifter locations, programmability (change switch function, change STI function, alter shift speed, etc). Do people need these things to ride a bicycle? No. Are they improvements over mechanical systems? Definitely. It's all where you place the value. I value it highly. It's been a game changer for me.

this is much better, imo, than "it shifts better under load" which, while probably true, sounds just like confirmation bias. Anyway, how big a pain is it to switch wheels where the cassette spacing is slightly different?

Got a very significant modified equipment TT coming up. This is Valley of the Sun - held mid Feb.
Rules are:
No TT bikes or TT frames, no aero Water bottles, wheels must have 16 spokes, mass start bike.

The Course is 6 miles straight north 270ft gain, turn around and back. Speeds are around 26mph out 29mph back. Winds blow west to east from still to a lot, but planning on about 5mph.

So - find high profile heavier or stick with 55mm?
Current wheels are 25mm wide, 55mm profile and very light with internal nipples. Most the 80mm profiles are 200g+ heavier / wheel and have external nipples.
There are economic considerations, but I'm not yet convinced 55mm->80 or more is better when picking up at least a pound.

From a Di2 perspective? You mean, what is the equivalent of a 1/4 turn of the shift cable adjuster?

Shift into the 4th cog (10sp) or 5th cog (11 sp)
Hold down the button on the front junction box for 3 seconds to put it in adjustment mode
Click the large shift button while spinning the pedals until you hear the chain grinding the inner cog
Click the small shift button either 4 or 5 times depending on whether you want a neutral shift bias or a downshift shift bias

It took me about 10x as long to type this than to do it. You can always tweak in place but I prefer to go through the whole routine.

Shovelhd made it sound complicated but it's trivial to trim the RD on the fly, while riding. You press a button and then your right shifter turns into an RD trim adjuster. Press the button again and you're done.

Ygduf, the FD shifting improvement is not confirmation bias, I promise. Di2 will shift under conditions that are simply guaranteed to drop the chain with a mechanical setup. The combination of a very strong motor (it can break your finger in the stand) and consistent precision just can't be matched with a mechanical setup. You might not notice when you are shifting in a careful, controlled way, but when you need to make a desperate front shift under high load it is magical.

Also multishift both up and down, and the ability to shift both derailleurs simultaneously while multishifting without dropping the chain or grinding.

You guys are really starting to make me think about Di2, previously it wasn't even in question. Should have considered it more when I built my new CAAD10

Puppy Doge has current 9000 Di2 and started riding on 1st generation Di2 and we just removed Mectronic from his TT bike and put Di2. I am the mechanic. That's 3 Shimano Di2 RD in the house (and yes we also have cables) with every button available to shift them (inc. the sprinters buttons). I think it is the best choice (I like Campy too), but there are issues because its so good.

It gets taken for granted - which is good - I think. But so much so that he has dropped the chain twice in competitive situations. This year it cost him to lose the main group by 2 min in the Nationals RR and Shimano support to fix the jam which resulted in another mechanical issue (so much for my excuses thread). If he had had cables he would not have tried that shift, or taken longer to do it properly. I realize 100 or so shifts he made with Di2 would have dropped on a cable system (He dislikes SRAM RED, but never dropped a chain), its just that when mechanical shifting you tend to pay more attention. The beauty of Di2 is you don't (normally) have to pay attention.
There is a local lower tier pro team that has a no cost to them choice of Di2 vs. cables. They use cables.

So we finally installed a chain catcher and we're good to go I hope.

The rings on the 9000 are just superior and the chain is relatively happy to move when you push it. Also - there is a lot of force. They give you a little steel tube protector as the FD leverages against the tube. The next-gen bikes need a beefier FD hanger.

what do you mean "superior?" is it stiffer, chain teeth configuration more shifting friendly, because I thought the cranks were totally the same for di2 and dura ace/ultegra.

Di2 cranks are the same. I often hear Di2 compared to non-Shimano cable stuff.

Compared to non DA, DA is stiffer, chain moves off easier and on easier. Compared to SRAM Red FSA uh - haven't tried everything. Road Campy for years. Campy looked better, lasted longer and didn't work as well.

somewhere, it says ultegra cranks are slightly stiffer, but with a weight penalty. but idc, ultegra is enough for me.

I was comparing to non Shimano stuff. We have Ultegra too. I have no scientific data to know which is stiffer. Ultegra may be. Generally Di2 is judged using 9000 rings. Those rings alone make a difference, or solely based on experience not any lab tests - comparing Di2 on 9000 rings to non Di2 on non 9000 rings is not close to a valid test. Compare Shimano Di2 on 9000 rings to Shimano cables and Shimano FD and RD on 9000 rings. That is a comparison I cannot personally make. But my gut is - they are real close. And, as posted, some really really good racers choose cables.