dura ace 9100 can't cross chain

[TobinHatesYou]

Lots of guys don't race and have never been forced to cross-chain. For sure, it isn't ideal, but sometimes you have no reasonable choice.

I try to keep front shifts to a minimum, especially when running Q-Rings. So the reality is if I do cross-chain it will be big-big and almost never small-small. Big-small to small-small is just a bad habit with how quickly you can blast through cogs on any modern drivetrain.

[PinaF8]

This is what happen when you try to put down big power in small to small.

[TobinHatesYou]

This is what happen when you try to put down big power in small to small.

That’s true... With many bikes using compact rings, small-small is barely even usable because the chain will graze the big ring. With compact Q-Rings, you even get that rub in the 10th cog.

[ms6073]

I think the cross chain restriction is imposed by the DI2 software on the 9150 RD because of its design compared to the traditional 9070 design.

Actually it is the 9100 Di2 shifters, not the derailleurs. Found this out when I upgraded wife's ST-9070 shifter with ST-R9150 shifters while keeping the FD9070 and RD9070 derailleurs, for when I updated the firmware and set the 50/34 chainring sizes and 12-28 cassette, no more small/small cross chaining until I changed the chainring size back to 52/38 or 53/39.

[PinaF8]

I think the cross chain restriction is imposed by the DI2 software on the 9150 RD because of its design compared to the traditional 9070 design.

Actually it is the 9100 Di2 shifters, not the derailleurs. Found this out when I upgraded wife's ST-9070 shifter with ST-R9150 shifters while keeping the FD9070 and RD9070 derailleurs, for when I updated the firmware and set the 50/34 chainring sizes and 12-28 cassette, no more small/small cross chaining until I changed the chainring size back to 52/38 or 53/39.

I changed only my RD to 9100 and it prevents me from going small to small without playing with gear ratios. My guess is software and RD and not the shifters.

[Mr.Gib]

This is what happen when you try to put down big power in small to small.

That’s true... With many bikes using compact rings, small-small is barely even usable because the chain will graze the big ring. With compact Q-Rings, you even get that rub in the 10th cog.

Except with the Sram 22 stuff. The chain clears the teeth of the big rig when in small/small. I don't understand why other manufactures aren't able to achieve this.

I use small small sometimes on my Sram equipped bikes. It is not a gear that anyone rides around in but there are some spots with a dip in the middle of the climb where it would be silly to go to the big ring just to avoid the 11 tooth cog for 50 metres, or attacking the bottom of a very steep hill where you know it would be a bad idea to drop from the big to the small under power, etc. It's situational and nice to have.

[ms6073]

This is what happen when you try to put down big power in small to small.

That looks more like what happens when you try to rejoin hollow link pins with the wrong tool.

[TobinHatesYou]

I wouldn’t bet on that pin having been messed with outside of the factory considering the quicklink...

[coloclimber]

I want to go small small when setting up a new change to check length. When I did the 11sp Shimano method of big big + 1.5 links and the new master link the chain was too long. I am able to dial in the RD tension screw too in small small and verify in big. Other than that I probably dont use and shouldnt use small small on the road but would take whatever gear I could get in a XC race blurry eyed. .

[Greatestalltime]

Old thread, but...I like 52-25. If I upgrade my firmware on my 9070 will I know longer have this option?
I’ve only had this a month. I tried to pair and update and it crashed and I had to unplug the battery. Guess I’m glad I did.

My main reason for staying on the big ring is to avoid chain smack on my new frame and it’s what I’m used to.

[BdaGhisallo]

Old thread, but...I like 52-25. If I upgrade my firmware on my 9070 will I know longer have this option?
I’ve only had this a month. I tried to pair and update and it crashed and I had to unplug the battery. Guess I’m glad I did.

My main reason for staying on the big ring is to avoid chain smack on my new frame and it’s what I’m used to.

I have one bike with 9070 and another with 9150 DI2, both with the latest firmware. I use 53-39 rings and 12-28 cassettes and I can put the chain in whatever chainring-cog combination I want. I think you need to have 53-39 rings and need to de-select the 'gear control' option in the E-Tube software to enable this or, rather, disable the system preventing you from accessing the smallest two cogs on the cassette when in the small chainring.

[hlvd]

I love big big.. small small not so much

I'm guilty of big big often, usually when I'm close to the top and don't want to change down, small small not so much.

[TobinHatesYou]

I love big big.. small small not so much

I'm guilty of big big often, usually when I'm close to the top and don't want to change down, small small not so much.

Big-big situations for me are short and shallow ramps up to 3% or so. I'll shift to the small ring for anything longer than about 20s. For everything else, my shifting revolves around cogs 4 and 6. If I I'm in a situation where I need to shift to the 3rd cog, then I'll shift down the the small ring and shift up the the 6th cog. For me that's typically shifting from 50x22 to 34x17 instead of 50x25...aka the same gear ratio. Conversely, if I need to shift up to the 7th cog, then I shift to the big ring and shift down the cassette to the 4th cog.

[Calnago]

Old thread, but...I like 52-25. If I upgrade my firmware on my 9070 will I know longer have this option?
I’ve only had this a month. I tried to pair and update and it crashed and I had to unplug the battery. Guess I’m glad I did.

My main reason for staying on the big ring is to avoid chain smack on my new frame and it’s what I’m used to.

Big/big should be fine. It’s small ring/ smallest two cogs it will lock you out of in the default setting.

[Greatestalltime]

Old thread, but...I like 52-25. If I upgrade my firmware on my 9070 will I know longer have this option?
I’ve only had this a month. I tried to pair and update and it crashed and I had to unplug the battery. Guess I’m glad I did.

My main reason for staying on the big ring is to avoid chain smack on my new frame and it’s what I’m used to.

Big/big should be fine. It’s small ring/ smallest two cogs it will lock you out of in the default setting.

Thanks. So I guess I’m good to update.