datlas 

I finally joined the 21st century and had a friend upgrade my Roubaix with Ultegra Di2 11 speed. I kept the 6700 crankset and brakes.

He tells me the setup has 1st generation 11s shifters and 2nd generation 11s RD/FD.

The system shifts great and although I have only used it a few times, I am overall pleased with it.

I so far have only one concern: the setup will NOT let me use the two smallest cogs in back when on the small ring in back. I can use all cogs in back when on the big chainring.

I mentioned this to my friend who set this up, he said this is the default of the system to prevent cross-chaining, and to over-ride this you need a computer setup which he does NOT have.

I suppose I can get used to not having my 11t and 12t when in the small ring, but it kinda rubs me the wrong way that I can't use these gears occasionally on an-as needed basis.

The whole electric shifting thing is still mostly a black box to me, but I expect there is some good knowlege here. Suggestions?? Easy Fix? Suck it up, buttercup???

Pic



PS. Note this is 11s Di2. I believe the 12s works differently. Thanks for any/all suggestions.

blacknbluebikes 

Really, I don't think you'll miss it that much. I ride both mech and di2, and it's so darned easy to be shifting front and back simultaneously, that I'm usually dancing in the mid-cog more than ever, except significant hills.

BTinNYC 

Sounds like Gear Position Control.

https://bettershifting.com/di2-cant-...ng-adjust-gpc/

datlas 

Thanks, that looks about right. I may have to find a friend who is able to do this. It's way beyond my capabilities.

choddo

Not sure there is any “as needed” to use those two gear combinations to be honest. You’re probably already into the equivalent of the 4th/5th cog on the back with the large chainring at that point.

spelger

why would you even want that gear combo? personally, once i'm half way through the back end i'm up on the big ring. little-little is something i never do.

Turnin_Wrenches

... I'm concerned that you are concerned . Why oh why would you want to knowingly ride in a fully cross-chained combination of gears?

Aaaaaaaaaaaaaahhhhhhhhhhhhhhhhhh... make it stop !!!

... OK, do what you want... but I do not comprehend this insanity.

datlas 

If I am on a mild incline that is leveling off, and I want to go just one or two gears bigger, especially when I KNOW we are going to hit a stop sign soon, I don't want to bother with going to the big ring.

I don't use these often but sometimes I want to be able to.

choddo

Is there a reason not to be in the big ring (and presumably a biggish cog) at a stop sign? Doesn’t Di2 actually make this really easy to do quickly?

datlas 

Yeah. Try starting from a full stop in the big ring. Not easily done, at least for me.

phrantic09

There’s an easy solution. Become too fat for this sport.

seypat

If it's fixable with a computer setup, I'd find a computer setup you/your buddy can fix it on. I do agree with your reasoning on why it needs to be fixed. One of my pet peeves is those at the front of the group that doddle and slowly get across an/the intersection. The people at the back of the group get hung out to dry as the traffic starts up again.

Iride01 

I kinda sorta felt the same way about not being able to use the 2 small cogs when in the small front when I got my first experience with 11 speed Di2. I got over it quickly. You just learn to shift to the big ring earlier where there are the same or almost the same gear ratios available.

In fact I found that I like to run the Di2 in full synchronized mode so I never even have to think about it. And for the most part, the shift levers on my left STI haven't been used but for a few very rare instances since going exclusively to full synchro.

So this part of your post is very appropriate....

eduskator

It's called dumb-proofing and you shouldn't cross-chain as there is no good reason to. The system shouldn't let you use the 2 hardest gears in the back when you're on the small ring and shouldn't let you use the 2 easiest gears in the back when you're on the big ring.

If you really want to do it and you don't mind you chain rubbing on the FD cage, you can probably circumvent this by connecting your bike to the E-TUBE app via the computer or your phone if you have the bluetooth adaptor (11sp DI2 requires a separate adapter to be bought while 12sp DI2 are bluetooth enabled) and enabling it.

choddo

I pretty much always do unless I’m on a gradient. Gives you more time to clip in too, because you get more distance/time for your one push on the pedal.

choddo

You need to be in the right gear (I always aim for the middle of the cassette when coming to a stop) but this doddling seems more likelyif you’re in the small ring?

Besides, you can always change gear while stopped by pulling the front brake and pushing on the bars to lift the rear wheel as you rotate the crank.

datlas 

I agree that cross-chaining is "poor form" and can cause some extra wear on the drivetrain. That said, there are occasonally times when I want to be able to use the smaller cogs on back when in the small ring (see above) and if I want to use that combination for 30 seconds periodically, I don't see that as such a bad thing.

I will ask a computer savvy bike friend if they are able to help me with this.

genejockey 

"I went to the doctor. I said, 'It hurts when I go like that.' He said, 'Don't go like that.'"

eduskator

Good idea. If you have a PC (Mac is not supported), you can install the E-TUBE software and connect your bike to your computer through the USB port. It should recognize it and you should be able to play with the settings on your PC through the software. You will most likely have a few updates to download and install at the same time.

rm -rf

The older Di2 6850 allowed this small chainring -- smallest cog cross chain.

Last year, I upgraded the rear derailleur to the newer 8050. I don't think there's a way to override the small ring, two smallest cog lockout. I thought this was going to be quite annoying, but I don't really notice any downside to this lockout. I used to do the small-small cross chains occasionally, but the chain "ticked" on the big chainring's shifting pickup pins. Ha, that did tell me when I was cross chained!

I have the older charging cable & control box, but that model isn't compatible with the new 8050. So I had the local bike shop do the firmware update. I've used e-tube with the old 6850, and it's easy.

spelger

i agree with your use case, but that would be a lot of rubbing. i do it too but just not that gear combo. i don't mind a little rubbing for a short time, to get over the hill but certainlyu not little-little.

yo must have the Di2 set up as manual as can be. i do too. if it were one of the other ways then i think it would shift to the big ring for you. i did not like that config so when full manual.

Iride01 

I don't think the restriction is for X-chain reasons. It is for the ability of the RD to be able to take up the chain slack when the chain is sized for cassettes with bigger rear cogs.

On my version of Di2 the cassette size in the e-Tube setup can be changed to a 11-26 or maybe n-27 and it will shift to those two smaller cogs. Physically the size of the cassette doesn't matter to the Di2 RD or E-tube it'll just have the gear ratios presented to you wrong when you look at the set up for them or on a Garmin or other device capable of communication with your Di2, it'll show the wrong ratios or tooth counts if you choose to display that information.

Shadco 

Ultegra 12 speed Di2 would allow this but I use semi sync instead, when I select the 13t cog whilst on the small ring it automatically goes to the big ring and moves back up the cassette a pre determined number of cogs. Works the same the other way in the big ring if I select a shift that would move to the 27t cog it drops to the small ring and goes down the cassette. It’s brilliant and keeps me in the middle of the cassette as much as possible. Once you get used to it you can anticipate the auto shift and do it manually if conditions make sense to do so.

.

Turnin_Wrenches

^ This doesn't make sense to me. When you size a chain for a mechanical groupset in which the rider can shift into "small-small" the RD deals with that just fine. It's a very bad gear combination for sure, but it shouldn't create excess slack in the chain.

Proper chain management for cassette cogs of various tooth counts is why rear derailleur cages come in different lengths.

choddo

It will reduce tension though (and therefore increase chain slap and maybe increase risk of losing your chain) because the force exerted by any spring is proportional to its extension and you’ve got 2 springs there both closer to their rest length when in small/small. (Might only be the pulley spring that affects the chain tension as I think about it)