Shimano Di2 and Bigger Cassette

Tomollandudno
Tomollandudno Posts: 1
edited March 14 in Workshop

Hi, Looking for some advice please. I own a bike with 10 speed Ultegra Di2 with a RD-6770 Mech and 12/25 Cassette on the rear, 50/34 up front. Ive moved to an area with some very steep hills and want a lower Gear. Some online forums suggest a 12/30 can work with this rear mech but Shimano info Says 12/28 is the Max.

I'm wondering if those people who say it can work are actually talking about a slightly newer mech?

Does anyone have personal experience of using a RD-6770 Mech with a 12/30 and 50/34 set up? does it work? Will I need a Longer Chain? Also Has anyone changed to 12/28, is there much disernable difference?

Would very much appreciate knowing what to splash out on, Thanks in advance

Comments

  • laurentian
    laurentian Posts: 2,623

    Mate, this forum closes for good on Monday so probably not the best time for you to make your first post. Many people from here have migrated to Cyclechat where there are similar chats and advice

    https://www.cyclechat.net/


    PS I've never used Di2 so can't offer a reply

    Wilier Izoard XP
  • oxoman
    oxoman Posts: 704

    You will be fine with a 28 probably without extra links unless your running a tight chain. A 30t is also doable but extra links required. If the new areas are really lumpy then might be worth considering changing your crankset depending on what your running up front. Your probably looking at shimano grx 48/31 or look at fsa or similar compact cranksets. If not 100% happy doing it might be worth finding a decent local bike mechanic. I did similar to.you but with a cyclocross come gravel bike, but with mechanical groupset. Eventually went 1x11 on that. Also as Laurentian says, unfortunately this forum is closing.

    Too many bikes according to Mrs O.
  • trevor.hall12
    trevor.hall12 Posts: 521

    If it affordable best option is to upgrade your rear derailler to R8070 ,can be bought for 160

    That would open up your rear shifting to an 36t cassette as it has the longer cage and drop pivot .

    Ive just done this to My wife's bike with the 8070 using an Airbike 36t cassette and all it needed was a tweak on the b limit screw


    Airbike cassettes are also only 36 quid .

    Your option youre asking about is workable but everything is on its limit

    You also have the option of a roadlink to drop the RD too to fit your bigger cassette

  • super_davo
    super_davo Posts: 1,254
    https://forum.bikeradar.com/discussion/comment/21119352#Comment_21119352

    I don't think you can with 10 speed 6700 - though would be a good option for 6800.

  • trevor.hall12
    trevor.hall12 Posts: 521
    https://forum.bikeradar.com/discussion/comment/21119354#Comment_21119354

    My mistake ,I read it as 6800

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