dura ace 9100 can't cross chain

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Rick
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by Rick

hmmm....I have been cross chaining relentlessly for 20+ years, both small-small and big-big, and I deliberately carefully adjust my derailleurs so I can do it without any rubbing. Who knew I was doing a bad thing all this time ?!?! :lol:

Admittedly, it has never been on DI2; always mechanical.

TobinHatesYou
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by TobinHatesYou

Rick wrote:
Tue May 29, 2018 3:26 am
Who knew I was doing a bad thing all this time ?!?! :lol:
A lot of people? It's inefficient, it wears your chain faster. It sounds worse whether there is cage rub or not.

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Rick
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by Rick

Believe it or not, sometimes efficiency, chain wear, and increase in chain sound is the least of your worries. :beerchug:

srshaw
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by srshaw

I always feel faster in the big chainring. Who cares about efficiency.

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by TobinHatesYou

Rick wrote:
Tue May 29, 2018 7:39 pm
Believe it or not, sometimes efficiency, chain wear, and increase in chain sound is the least of your worries. :beerchug:

Have the presence of mind to shift your FD earlier. My shifting strategy almost never changes. I shift to the small ring when I would have to shift down to the 3rd cog. I shift up to the big ring when I would otherwise have to shift to the 7th cog. Not only is this optimal for chainlines, it's also the best point to synchro-shift on a SRAM 11-32 (11-12-13-14-15-17-19-22-25-28-32.) Going up to 50/25 is the same as going down to 34/17 and only requires two rear shifts. The only times I deviate from this is when I know a grade change is very short, then I will utilize the 1-3 cogs with the big ring. I pretty much never use the small ring in conjunction with the 9-11 cogs.

mattr
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by mattr

Rick wrote:
Tue May 29, 2018 3:26 am
and I deliberately carefully adjust my derailleurs so I can do it without any rubbing.
Some combinations physically can't be done without rubbing. Which you cannot adjust out. As the chain is rubbing the chainrings.
You could (i suppose) space the chainset over or extend your chainstays, but neither is practical, or particularly desireable........

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by TobinHatesYou

mattr wrote:
Wed May 30, 2018 7:59 am
Some combinations physically can't be done without rubbing. Which you cannot adjust out. As the chain is rubbing the chainrings.
You could (i suppose) space the chainset over or extend your chainstays, but neither is practical, or particularly desireable........

Well if he's talking about FD cage rub, he shouldn't really be getting that with a Yaw derailleur if it's set-up correctly. The tail of the cage is very wide.

But yes, I get some chain contact with my big ring if I am in 34x11. GXP cranks, 410mm chainstays. Good thing 34x11 is a silly gear combo nobody should ever use.

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Rick
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by Rick

mattr wrote:
Wed May 30, 2018 7:59 am
Some combinations physically can't be done without rubbing. Which you cannot adjust out. As the chain is rubbing the chainrings.
You could (i suppose) space the chainset over or extend your chainstays, but neither is practical, or particularly desireable........
I can't really speak for all combinations, but I have been able to do it with all my bikes; and this is pretty standard racing geometry chainstay lengths, etc. (not "touring bikes" or anything like that.) Maybe I am just lucky. Ironically, I seemed to have the most trouble getting my Sram Red Yaw front derailleur perfect; but successive iterations finally got it there. My 34-11 works fine, even if nobody should ever use it. I do have a derailleur hanger alignment tool also, so maybe that helps.
Of course nobody really has to do this, you can never cross-chain if you don't want to. But it seems to work perfectly fine for me, and frankly, I need all the gears I can find. :)
(I know it doesn't really give more gears, but when under pressure to crest a hill with the bunch, etc, sometimes you don't want to double shift and you haven't anticipated the shifts correctly. Who is perfect on that sort of thing ?!?! )

plag
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by plag

Isn’t all the new 1X systems the same as cross chaining? Your going from one extreme to the other .



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by Nefarious86

plag wrote:Isn’t all the new 1X systems the same as cross chaining? Your going from one extreme to the other .



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Calnago
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by Calnago

plag wrote:Isn’t all the new 1X systems the same as cross chaining? Your going from one extreme to the other .
Yes it is, but the 1x crowd doesn’t like to talk of such things. Shhhhh.

And for what it’s worth, one click in the rear to go from 50/22 to 50/25 is a helluva lot more efficient than shifting to 34/17 any day under any circumstance, especially when you’re not even close to the extremities of an 11/32 cassette.
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by TobinHatesYou

Calnago wrote:
Wed May 30, 2018 3:31 pm

And for what it’s worth, one click in the rear to go from 50/22 to 50/25 is a helluva lot more efficient than shifting to 34/17 any day under any circumstance, especially when you’re not even close to the extremities of an 11/32 cassette.

1) 50/25 is where chainline starts hurting efficiency on most road bikes with short chainstays. There are times where I will go to 50x32 when I know it's just a short ramp, but
2) Moving to 34x17 is an anticipatory move as you know the grade will be increasing even more.
3) Shifting to 34x17 doesn't take me significantly more energy to shift on an electronic group.

And there's never really an analogous situation for going to 34x11.

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Calnago
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by Calnago

Since when is 50/25 where chainline starts hurting efficiency? Says who? You’re just making stuff up again. Number of teeth has nothing to do with chainline. It’s where that cog is positioned in the cassette that counts, and at the 3rd position down from the top, chainline is just fine, even on short chainstay bikes, of which there are becoming fewer and fewer. Is it as good as a straight line shot single speed system?... Of course not, but on a modern road bike it is fine. Whether it’s an electronic group or a mechanical group is completely irrelevant. I will give you that if that’s the point you like to shift your chainrings to anticipate something coming up then so be it, that’s an individual preference, but it’s your preference and may not be everyone’s. But it’s not hurting the system one bit and the drop from a 50 to a 34 is the most problematic shift of any of the three main road chainring combos as it entails the greatest physical drop distance and has the most potential for things going wrong.
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TobinHatesYou
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by TobinHatesYou

Calnago wrote:
Thu May 31, 2018 1:58 am
Since when is 50/25 where chainline starts hurting efficiency? Says who? You’re just making stuff up again. Number of teeth has nothing to do with chainline. It’s where that cog is positioned in the cassette that counts, and at the 3rd position down from the top, chainline is just fine, even on short chainstay bikes, of which there are becoming fewer and fewer. Is it as good as a straight line shot single speed system?... Of course not, but on a modern road bike it is fine. Whether it’s an electronic group or a mechanical group is completely irrelevant. I will give you that if that’s the point you like to shift your chainrings to anticipate something coming up then so be it, that’s an individual preference, but it’s your preference and may not be everyone’s. But it’s not hurting the system one bit and the drop from a 50 to a 34 is the most problematic shift of any of the three main road chainring combos as it entails the greatest physical drop distance and has the most potential for things going wrong.

We have been talking about 50x25 in relation to my 11-32t, which does hurt efficiency. You can hear it. Don't try to twist my words regarding cog sizes when we all know tighter bends means lower efficiency. As usual you seem determined to counter everything I say with screams of "fake news!" Give me a day or two, I'll find the source.

e: Nevermind, I already found it.

https://www.bikeradar.com/us/road/gear/ ... ing-44016/

"According to Friction Facts, the tipping point comes eight cogs in from the outermost cassette position – roughly two-thirds of the way across. On a modern drivetrain with 53/39t chainrings and an 11-28t 11-speed cassette, this means that if you’re in the 53-21t and need an easier gear, it’s better to drop down to the inner chainring and select the 39-17t combination instead of using the 53-23t one."

So besides your obsession with me, what's in it for you to falsely claim that 50x25 (2x3) doesn't hurt efficiency?

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Calnago
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by Calnago

I have no obsession with you, I just think a lot of the things you say are ill advised and quite frankly, kind of silly. I can only assume you are either quite new to all this cycling stuff, or so young, naive and gullible that you just haven't had enough experience to know when to depart from theoretical perfection to real world practicality. Nothing is "in it" for me to falsely claim that big ring and 3rd largest cog doesn't hurt efficiency, because in the real world it is just fine. I'm sorry your drivetrain is noisy using the big ring and the 3rd largest cog. I suppose I wouldn't want to go there either if that were the case. You should fix that.

I think I've seen you favorably touting the 1x drive trains, but think that most roadies won't switch until 1x14 is here. Really. Hmmm... we'll see. But how do you sleep at night knowing that on either side of those 8 cogs in the center, there are 3 more on either end that would be just so "inefficient" for you to consider using? It must be hard.

The poster who resurrected this thread simply was wondering if upgrading his di2 system would allow him to use big/big, and in his case that was a 25 cog. He likes that combo, for whatever reason. Di2 doesn't lock him out of that. So he's good, and he's happy.

And pretty sure if some pro were chasing some other pro up some climb in the big ring and his 3rd largest cog, and he felt he was going to blow up and needed that next easier gear to even hope of staying in contact, he's going to be clicking once to get to the second biggest cog and not faff about worrying about his chainline at that point. If you want to use the 4th largest cog as your cutoff point when you need to shift chainrings, that's up to you. My drivetrain is slient at that point, and beyond... I decide when the time is right to shift either front, rear, or both simultaneously, depending on the circumstance. It's ever changing.

Really, the leap between theory and practice isn't that big, you should try to reconcile the two in your mind occasionally.
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