Di2 Question

Sutton_Rider
Sutton_Rider Posts: 493
edited September 2019 in Workshop
I'm running a 50/34 and 11/28 on an SS rear mech and I've just installed Di2 on the bike. When in the 34 ring I can't change in to the 11t and 12t cog (not that you would want to). Is this normal or is it a setup issue I've not got right? I can get all gears when in the 50 ring.

Comments

  • StillGoing
    StillGoing Posts: 5,211
    Why would you not want to be able to use the 12 & 11 tooth sprockets when in the big ring?

    Your indexing is not right if you can't change into the the smallest gears when in the big ring. If you have 8050/8070, the synchro shift setting won't allow you to change into the top 3 or gears when in the small ring and the lowest gear when in the big ring. It would automatically change the front ring when you tried to change to those sprockets respectively.

    Re-index your gears.
    I ride a bike. Doesn't make me green or a tree hugger. I drive a car too.
  • Sutton_Rider
    Sutton_Rider Posts: 493
    Sorry philthy3, I got the rings round the wrong way, I've corrected my original post.
  • darkhairedlord
    darkhairedlord Posts: 7,180
    philthy3 wrote:
    Why would you not want to be able to use the 12 & 11 tooth sprockets when in the big ring?

    Your indexing is not right if you can't change into the the smallest gears when in the big ring. If you have 8050/8070, the synchro shift setting won't allow you to change into the top 3 or gears when in the small ring and the lowest gear when in the big ring. It would automatically change the front ring when you tried to change to those sprockets respectively.

    Re-index your gears.
    If you've just woken up have coffee and re-read the OP.
  • drexel1975
    drexel1975 Posts: 70
    This is the way that the new Di2 works. Unless you use E-Tube software to tell the system that you have another chainring combination then you can't use the 34 and the two smallest gears on the cassette. This is explained in the dealers manual which you can download from the Shimano website. I use a 52-36 crankset and also cannot use the two small gears. It's to stop crosschaining which can harm the gearing components.
  • Sutton_Rider
    Sutton_Rider Posts: 493
    Thanks drexel I'll have a look at the manual, but it seems that I've got it set up OK.
  • StillGoing
    StillGoing Posts: 5,211
    darkhairedlord wrote:
    philthy3 wrote:
    Why would you not want to be able to use the 12 & 11 tooth sprockets when in the big ring?

    Your indexing is not right if you can't change into the the smallest gears when in the big ring. If you have 8050/8070, the synchro shift setting won't allow you to change into the top 3 or gears when in the small ring and the lowest gear when in the big ring. It would automatically change the front ring when you tried to change to those sprockets respectively.

    Re-index your gears.
    If you've just woken up have coffee and re-read the OP.

    If you read the reply to me, you'll see that they changed the original post having put the wrong chainring. Back of the net. :D

    OP, in which case, yes you can't shift into the top 3 or 4 gears when in the inner ring without the front derailleur changing to the big ring. Likewise, you can't can't change into the bottom gear when in the big ring without the front derailleur changing to the inner ring. Your Di2 is working fine.
    I ride a bike. Doesn't make me green or a tree hugger. I drive a car too.
  • Sutton_Rider
    Sutton_Rider Posts: 493
    Yes thanks philthy3, I think your first reply was sent at the same time as I corrected my original post, hence the confusion, they crossed in the post as they say. My bad.
  • darkhairedlord
    darkhairedlord Posts: 7,180
    philthy3 wrote:
    darkhairedlord wrote:
    philthy3 wrote:
    Why would you not want to be able to use the 12 & 11 tooth sprockets when in the big ring?

    Your indexing is not right if you can't change into the the smallest gears when in the big ring. If you have 8050/8070, the synchro shift setting won't allow you to change into the top 3 or gears when in the small ring and the lowest gear when in the big ring. It would automatically change the front ring when you tried to change to those sprockets respectively.

    Re-index your gears.
    If you've just woken up have coffee and re-read the OP.

    If you read the reply to me, you'll see that they changed the original post having put the wrong chainring. Back of the net. :D

    OP, in which case, yes you can't shift into the top 3 or 4 gears when in the inner ring without the front derailleur changing to the big ring. Likewise, you can't can't change into the bottom gear when in the big ring without the front derailleur changing to the inner ring. Your Di2 is working fine.
    I noticed once I'd had a coffee.
  • pilot_pete
    pilot_pete Posts: 2,120
    And of course you can change the setup in eTube if you really want to cross chain...

    I tried syncro shift but didn’t like it, so mine is set up to replicate mechanical derailleurs. I found that after a fast descent in a high gear going straight into a steep climb requiring a really low gear, as I dropped to to the little front ring it would automatically drop me down a couple of cogs at the back to get the next ratio down, when I wanted to go straight to bottom gear!

    PP
  • -Dash
    -Dash Posts: 179
    Pilot Pete wrote:
    And of course you can change the setup in eTube if you really want to cross chain...

    I tried syncro shift but didn’t like it, so mine is set up to replicate mechanical derailleurs. I found that after a fast descent in a high gear going straight into a steep climb requiring a really low gear, as I dropped to to the little front ring it would automatically drop me down a couple of cogs at the back to get the next ratio down, when I wanted to go straight to bottom gear!

    PP

    I've found this too with the semi synchro shift. Generally when I shift the front it's because I want an easier or harder gear. I don't want what I effectively just had!
  • StillGoing
    StillGoing Posts: 5,211
    Pilot Pete wrote:
    And of course you can change the setup in eTube if you really want to cross chain...

    I tried syncro shift but didn’t like it, so mine is set up to replicate mechanical derailleurs. I found that after a fast descent in a high gear going straight into a steep climb requiring a really low gear, as I dropped to to the little front ring it would automatically drop me down a couple of cogs at the back to get the next ratio down, when I wanted to go straight to bottom gear!

    PP

    That's not correct with R8050 series unless you're running a 39/53 set up. The restriction is inbuilt into the design.

    I use synchro shift and have no issues with it. On ramps, it allows me to keep my cadence up without sudden RPM increases trying to catch the lower gearing and losing speed.
    I ride a bike. Doesn't make me green or a tree hugger. I drive a car too.
  • Alejandrosdog
    Alejandrosdog Posts: 1,975
    why cant we program our group sets with a personaisedpowerband consisting of power/ cadence and have fully automatic changing so we can achieve greatest steady state speed whilst maintaining our own personal optimal power use. Thats proper innovation.

    I don't want to think about what im doing or expend valuable energy changing gear.

    Imagine how good everyones tens on a dual carriageway would be.
  • wongataa
    wongataa Posts: 1,001
    Alejandrosdog wrote:
    why cant we program our group sets with a personaisedpowerband consisting of power/ cadence and have fully automatic changing so we can achieve greatest steady state speed whilst maintaining our own personal optimal power use. Thats proper innovation.
    You probably will be able to at some point.
  • Alejandrosdog
    Alejandrosdog Posts: 1,975
    wongataa wrote:
    Alejandrosdog wrote:
    why cant we program our group sets with a personaisedpowerband consisting of power/ cadence and have fully automatic changing so we can achieve greatest steady state speed whilst maintaining our own personal optimal power use. Thats proper innovation.
    You probably will be able to at some point.

    Stepforward triathletes and ironman contenders and PBP riders.

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