Third front sprocket to shimano 6800?

Trivia
Trivia Posts: 12
edited May 2017 in Workshop
I was wondering if it'd be possible to fit a third front sprocket to give you a bit of ease on uphills. I currently have Ultegra 50x34 do you know if it's possible or will i have to get a new crank altogether?

Comments

  • Thick Mike
    Thick Mike Posts: 337
    Trivia wrote:
    I was wondering if it'd be possible to fit a third front sprocket to give you a bit of ease on uphills. I currently have Ultegra 50x34 do you know if it's possible or will i have to get a new crank altogether?

    You will need a triple crankset and a triple shifter and front mech too. Not so straightforward unfortunately.

    Cheaper to swap to 46/30 on the front, or to get a bigger cog on the cassette (though you might need a longcage rear derailleur for that).
  • ugo.santalucia
    ugo.santalucia Posts: 28,335
    Don't think your shifters will allow you to have a triple chainring
    left the forum March 2023
  • Trivia
    Trivia Posts: 12
    Thanks for replies! I looked and couldn't fine 11 speed 46x30 from shimano anyway.
    - Are chainrings to some extent compatible between makes?
    - Is there a difference in cog spacing between 10 or 11 spd versions (shimano) or are they interchangeable?
  • dj58
    dj58 Posts: 2,224
    T A specialites make a 33T inner chainring which you could use with a 32T low rear sprocket, may be an option for you.
    https://specialites-ta.com/plateaux/roa ... nring.html
  • Trivia
    Trivia Posts: 12
    Thanks, done some more research and i think ill go with 11-32T and get a GS derailleur. That should cap at 120 euros, seems cheaper than other options, plus difference is greater than from 34 to 30 and i'm not losing higher gears.

    Thanks again :)
  • trailflow
    trailflow Posts: 1,311
    There is no such thing as a 46/30t chainset from Shimano. Their lowest compact road/cx cranks are 46/34t.

    A 46/30t crank is a called a super compact and is a relatively new release from FSA. But (i think) they are only available for pressfit BB''s (BB30,BB386)

    You can mix and match brands but the chainring needs to match the BCD (bolt circle diameter) and number of bolts.

    The smallest inner ring you can put on a 110bcd crank (5-bolt) is 33t.

    Your Ultegra 6800 crank has 4 arm , 4-bolt BCD pattern, so is only compatible with 4-bolt chainrings. i believe there are no 33t 4-bolt chainrings currently available, only 5-bolt.

    10 and 11spd chainrings are interchangeable. The spacing is fractionally smaller on 11spd but its not enough to cause any negative effects if you do mix and match.

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