Kai Winters

So it is a misstatement...when 'adjusting the gears' what is really being done is the rear derailleur is being aligned so the jockey pulley, and idler pulley I guess, is aligned with that particular gear so the chain isn't touching either the gear above or below...was this not understood when 'adjusting the gears' was mentioned? I suspect most of us know when this is said you are adjusting the derailleur as the 'gears' are only 'adjusted' if a spacer is used to move the cassette itself.
But I guess clarification is our friend...

One of the great benefits of electronic shifting is the ability to adjust the rear derailleur so it is precisely aligned to each gear of the cassette. A mechanical derailleur can't be adjusted this way but honestly we've used mechanical derailleurs for decades with few complaining of this inability. I've never considered it, whether possible or not, and I've been building bikes from the frame up since 5 speed friction shifters...yipes I'm old...long live 'straight blocks'

Mtracer

I don't think anyone thought you were literally saying physically aligning the gears. Here's your original statement:

And again in this last post:
What exactly do you mean by adjust "every" and "each" gear in the above statements? To me this sounds like you are saying the indexing can be fine tuned separately for each gear.

And what can you do with the Di2 that you cannot do with a mechanical in terms of adjustment? I'm not trying to argue, but twice now you've made statements that to me seem to be saying there is some way to adjust indexing individually for each gear. And if this is possible, I want to know how to do this.

If I misunderstood you and you simply mean the Di2 indexing is adjusted electronically, affecting all gears the same, similar to a cable tension adjustment, then that's fine. I simply read more into your statement than you meant.

Kai Winters

The rear derailleur on my 12 speed 105 Di2 system can be aligned for each gear on the cassette. I use the Etube app which moves the der into whatever alignment I want for each gear. The alignment is stored in the der's memory and when shifting into each gear it moves into the setting I've set it to. So the rear der is in fact individually aligned to each gear. This is not the case with a mechanical system. You align the rear der. using cable tension/spring loading in one gear to it's 'optimal' position which is then carried on with each shift. If a gear is a bit off you can adjust cable tension but by adjusting cable tension you affect all gears. Di2 does not work that way thus is individually adjustable.
In general this hasn't been an issue because the rear der, mechanical, does move in a precise location providing an efficient and quiet drive train. However as the cassette gears are closer together...11 speed, etc. the distance between the outer links of the chain are closer to the upper and lower gears. If the rear der isn't precisely adjusted and/or the cable and/or spring no longer holds the der in that exact position some rubbing sounds may occur requiring an adjustment. Most don't notice or perform enough routine maintenance that this adjustment is made.

You do have to manually set the upper/lower...high/low...limits with mechanical screws on the 105 system which is the same as all mechanical systems unlike Ultegra, etc which is done electronically.

I think this poor horse has been beaten enough and I'm done here...good luck everyone...I'm bored and moving on...

TerryDi2C

You cannot adjust the rear derailleur for each gear separately. It is one setting for the entire cassette.

It may look like that in the app, but there is only one adjustment setting for the entire RD/cassette .

Yes, you can go through each gear and change the adjustment/indexing value with the derailleur in any position you like... but you'll be changing the same setting/value. Perhaps I'll post a video tonight... in about 10 hours.

Mojo31

I have found this to be true as well. The goal is to find the best compromise.

Jughed

Here you go...

Shimano to recall 760,000 Ultegra and Dura-Ace cranksets due to crash risk | Cyclingnews

Maelochs

Worldwide recall to come as six injuries found in over 4,500 reported incidents of failing components .... out of 760,000 units sold.

That says a lot for Shimano.

Maelochs

Now I have to go look at my cranks .... ugh.

88ss

Nice thread, after reading it I hope to convert to the 105 D12 that a few of my riding buddies are using and doing well with, nice to know it is doing well for everyone else too.

SoSmellyAir

I guess we all just assumed the OP was talking about the current, 12-speed generation because he is comparing 105 Di2 and Ultegra Di2?

The crank issue has only been reported for the prior 11-speed generation of Ultegra and Dura-Ace HollowTech cranks. (I am not suggesting that it is impossible for the current generation to have the same problem; I am just not aware of any reports thereof.)

georges1

Take the the Ultegra if you can afford it otherwise the 105 is outstanding value for money