Rear derailleur compatibility across 9,10 and 11 speeds
Results 1 to 19 of 19
  1. #1
    RoadBikeReview Member
    Reputation:
    Join Date
    Jun 2005
    Posts
    220

    Rear derailleur compatibility across 9,10 and 11 speeds

    This is a question that’s been on the back burner for a while now. Thought this would be the perfect time to lay it out here.
    1. Rear derailleur works by the pulley moving across the width of the cassette. The cable pull is regulated by the amount of cable pull within the shifter mechanism. What’s stopping me from using a older model 8 speed derailleur with a 11 speed shifter? Or a 9 speed? The cassette hub is a constant fixed width. The only variable is the spacer width and the cog thickness. Theoretically, setting the high and low limits should take care of that. Let’s have the yay’s and nay’s on why it should or shouldn’t work.


    Sent from my iPhone using Tapatalk

  2. #2
    tlg
    tlg is offline
    RoadBikeReview Member
    Reputation: tlg's Avatar
    Join Date
    May 2011
    Posts
    16,847
    Been asked about a bazillion times. 100% Nay won't work. The pull ratios are different.
    Custom Di2 & Garmin/GoPro mounts 2013 SuperSix EVO Hi-MOD Team * 2004 Klein Aura V

  3. #3
    'brifter' is f'ing stupid
    Reputation: cxwrench's Avatar
    Join Date
    Nov 2004
    Posts
    15,147
    8, 9, and 10 are the same cable pull ratio...except for 4700. It's 10 speed but the cable pull is the same as 6800/8000 and 9000/9100. You can use the 8 speed derailleur w/ any 8 or 9 speed shifter, and all 10 speed shifters except 4700 Tiagra. It won't work w/ ANY 11 speed shifter. You can use the 8 speed derailleur w/ any 8 or 9 speed mtb shifter as well, but no 10 speed (Dyna-Sys) shifter will work.
    #promechaniclife

  4. #4
    RoadBikeReview Member
    Reputation:
    Join Date
    Feb 2002
    Posts
    21,325
    Quote Originally Posted by arshak View Post
    This is a question that’s been on the back burner for a while now. Thought this would be the perfect time to lay it out here.
    1. Rear derailleur works by the pulley moving across the width of the cassette. The cable pull is regulated by the amount of cable pull within the shifter mechanism. What’s stopping me from using a older model 8 speed derailleur with a 11 speed shifter? Or a 9 speed? The cassette hub is a constant fixed width. The only variable is the spacer width and the cog thickness. Theoretically, setting the high and low limits should take care of that. Let’s have the yay’s and nay’s on why it should or shouldn’t work.
    As others have noted, as long as the cable pull is consistent then it will work. But when you say "older" derailleur, you might find that a newer 8s derailleur will work better than an older 8s derailleur just because there are improvements in derailleurs over time. Might not be an issue in your specific application.

  5. #5
    RoadBikeReview Member
    Reputation:
    Join Date
    Oct 2013
    Posts
    4,153
    So, how exactly are you going to get to 9,10, & 11 speed gears? ... when the shifters only go to ...8?
    I think you're going to be missing some gears!
    BANNED

  6. #6
    RoadBikeReview Member
    Reputation:
    Join Date
    Feb 2002
    Posts
    21,325
    Quote Originally Posted by duriel View Post
    So, how exactly are you going to get to 9,10, & 11 speed gears? ... when the shifters only go to ...8?
    I think you're going to be missing some gears!
    Reading comprehension issues or trolling? The OP said "8 speed derailleur with a 11 speed shifter"

  7. #7
    RoadBikeReview Member
    Reputation:
    Join Date
    Oct 2013
    Posts
    4,153
    OK, I got it backwards. I guess I got mixed up with another thread about/with a 11 spd hub/wheel.
    BANNED

  8. #8
    Banned Sock Puppet
    Reputation: Lombard's Avatar
    Join Date
    May 2014
    Posts
    11,404
    Quote Originally Posted by cxwrench View Post
    8, 9, and 10 are the same cable pull ratio...except for 4700. It's 10 speed but the cable pull is the same as 6800/8000 and 9000/9100. You can use the 8 speed derailleur w/ any 8 or 9 speed shifter, and all 10 speed shifters except 4700 Tiagra. It won't work w/ ANY 11 speed shifter. You can use the 8 speed derailleur w/ any 8 or 9 speed mtb shifter as well, but no 10 speed (Dyna-Sys) shifter will work.
    Exactly this. Shimano changed the cable pull ratio on 11-speed road and 10-speed mountain to pull more cable.

    Unless this 8-speed rear derailleur is one you have lying around your bike parts pile, why would you want to buy an 8-speed one when 11-speed rear derailleurs are relatively cheap anyway?
    "COMPLACENCY IS LETHAL - VOTE in November." - System Shock.

    "With
    bicycles in particular, you need to separate between what's merely true and what's important."
    -- DCGriz, RBR.





  9. #9
    RoadBikeReview Member
    Reputation:
    Join Date
    Jun 2005
    Posts
    220
    Quote Originally Posted by duriel View Post
    So, how exactly are you going to get to 9,10, & 11 speed gears? ... when the shifters only go to ...8?
    I think you're going to be missing some gears!
    I think you misunderstood me. The shifters will be the change in the constant. If I use 11 speed shifters with 8 speed Dura Ace rear derailleur, the cable pull will be regulated by the shifters themselves. If the hub width remains a constant as well, wouldn’t the 8spd rear derailleur work just as well?


    Sent from my iPhone using Tapatalk

  10. #10
    RoadBikeReview Member
    Reputation:
    Join Date
    Jun 2005
    Posts
    220
    Quote Originally Posted by Lombard View Post
    Exactly this. Shimano changed the cable pull ratio on 11-speed road and 10-speed mountain to pull more cable.

    Unless this 8-speed rear derailleur is one you have lying around your bike parts pile, why would you want to buy an 8-speed one when 11-speed rear derailleurs are relatively cheap anyway?
    Lockdown blues and boredom. I have an old DA 8 speed derailleur in the spare parts bin. Will update if my theory holds or not as the case maybe.


    Sent from my iPhone using Tapatalk

  11. #11
    Banned Sock Puppet
    Reputation: Lombard's Avatar
    Join Date
    May 2014
    Posts
    11,404
    Quote Originally Posted by arshak View Post
    I think you misunderstood me. The shifters will be the change in the constant. If I use 11 speed shifters with 8 speed Dura Ace rear derailleur, the cable pull will be regulated by the shifters themselves. If the hub width remains a constant as well, wouldn’t the 8spd rear derailleur work just as well?
    No, an 11 speed road shifter has a different pull ratio than an 8, 9 or 10 speed. Any 8, 9 or 10 speed road shifter will work with any 8, 9 or 10 speed road rear derailleur (unless it's Tiagra 4700). However, the 11 speed road system pulls more cable per shift and therefore is not backwards compatible.

    I'm still not sure what you are trying to do here. What do you have on your bike as far as shifters, rear derailleur and cassette and what is it you are trying to change?
    Last edited by Lombard; 1 Day Ago at 06:02 PM.
    "COMPLACENCY IS LETHAL - VOTE in November." - System Shock.

    "With
    bicycles in particular, you need to separate between what's merely true and what's important."
    -- DCGriz, RBR.





  12. #12
    'brifter' is f'ing stupid
    Reputation: cxwrench's Avatar
    Join Date
    Nov 2004
    Posts
    15,147
    Quote Originally Posted by arshak View Post
    I think you misunderstood me. The shifters will be the change in the constant. If I use 11 speed shifters with 8 speed Dura Ace rear derailleur, the cable pull will be regulated by the shifters themselves. If the hub width remains a constant as well, wouldn’t the 8spd rear derailleur work just as well?


    Sent from my iPhone using Tapatalk
    Nope. The cable pull is regulated by the shifter but not how much the derailleur moves. That's a combination of cable pull and derailleur geometry.
    #promechaniclife

  13. #13
    RoadBikeReview Member
    Reputation:
    Join Date
    Jun 2005
    Posts
    220
    Quote Originally Posted by Lombard View Post
    No, an 11 speed road shifter has a different pull ratio than an 8, 9 or 10 speed. Any 8, 9 or 10 speed road shifter will work with any 8, 9 or 10 speed road rear derailleur (unless it's Tiagra 4700). However, the 11 speed road system pulls more cable per shift and therefore is not backwards compatible.

    I'm still not sure what you are trying to do here. What do you have on your bike as far as shifters, rear derailleur and cassette and what is it you are trying to change?
    Like I said, lockdown boredom and the fact that I have an old 8 speed kicking around. Believe it or not I have managed to get a 10 speed Rival derailleur work with a 9 speed cassette with help from 9 speed Campy Daytona. I will keep you updated on this thread as to where the boredom driven rabbit hole leads me. ‘Tis curiouser & curiouser said the bunny wabbit


    Sent from my iPhone using Tapatalk

  14. #14
    Banned Sock Puppet
    Reputation: Lombard's Avatar
    Join Date
    May 2014
    Posts
    11,404
    Quote Originally Posted by arshak View Post
    Like I said, lockdown boredom and the fact that I have an old 8 speed kicking around. Believe it or not I have managed to get a 10 speed Rival derailleur work with a 9 speed cassette with help from 9 speed Campy Daytona. I will keep you updated on this thread as to where the boredom driven rabbit hole leads me. ‘Tis curiouser & curiouser said the bunny wabbit.
    Haha! OK. Not sure about SRAM compatibilities. I'd have to look that up. CXWrench would know for sure. But hey, if you're bored, try 'em all, LOL!
    "COMPLACENCY IS LETHAL - VOTE in November." - System Shock.

    "With
    bicycles in particular, you need to separate between what's merely true and what's important."
    -- DCGriz, RBR.





  15. #15
    RoadBikeReview Member
    Reputation:
    Join Date
    May 2010
    Posts
    9,501
    Quote Originally Posted by Lombard View Post
    No, an 11 speed road shifter has a different pull ratio than an 8, 9 or 10 speed. Any 8, 9 or 10 speed road shifter will work with any 8, 9 or 10 speed road rear derailleur (unless it's Tiagra 4700). However, the 11 speed road system pulls more cable per shift and therefore is not backwards compatible.
    If that's true then theoretically an 8 speed der will over shift because it was designed to move further with less cable being pulled.

    Try it to find out. "more" cable being pulled doesn't necessarily mean it's not still be 'close enough', It won't be perfect but wouldn't shock me if it worked acceptably.

  16. #16
    xxl
    xxl is offline
    Moderator
    Reputation: xxl's Avatar
    Join Date
    Mar 2002
    Posts
    38,810
    Quote Originally Posted by cxwrench View Post
    Nope. The cable pull is regulated by the shifter but not how much the derailleur moves. That's a combination of cable pull and derailleur geometry.
    Yep. Metaphorically, the derailleur is the big dumb boyfriend doing all the heavy lifting while the shifter is the cute girlfriend calling the shots and telling him where she wants the furniture placed.
    More Americans wanted Hillary Clinton to be President than wanted Donald Trump.

    Donald Trump has never had a wife he didn't cheat on.

    There are over 5.2 million covid cases in the United States (as of August 12), seven months after Donald Trump said it was "totally under control," and that "it's gonna be just fine."

  17. #17
    Banned Sock Puppet
    Reputation: Lombard's Avatar
    Join Date
    May 2014
    Posts
    11,404
    Quote Originally Posted by Jay Strongbow View Post
    If that's true then theoretically an 8 speed der will over shift because it was designed to move further with less cable being pulled.
    Yep.

    Quote Originally Posted by xxl View Post
    Yep. Metaphorically, the derailleur is the big dumb boyfriend doing all the heavy lifting while the shifter is the cute girlfriend calling the shots and telling him where she wants the furniture placed.
    Hahah! Good analogy!
    "COMPLACENCY IS LETHAL - VOTE in November." - System Shock.

    "With
    bicycles in particular, you need to separate between what's merely true and what's important."
    -- DCGriz, RBR.





  18. #18
    RoadBikeReview Member
    Reputation:
    Join Date
    May 2010
    Posts
    9,501
    Quote Originally Posted by xxl View Post
    Yep. Metaphorically, the derailleur is the big dumb boyfriend doing all the heavy lifting while the shifter is the cute girlfriend calling the shots and telling him where she wants the furniture placed.
    Kind of the opposite in this situation. Instructions on placing the furniture are a given.
    The cable pull from the shifters is what it is no matter what. Different ders make different decisions on placing the furniture with the same instructions.

  19. #19
    xxl
    xxl is offline
    Moderator
    Reputation: xxl's Avatar
    Join Date
    Mar 2002
    Posts
    38,810
    Quote Originally Posted by Jay Strongbow View Post
    Kind of the opposite in this situation. Instructions on placing the furniture are a given.
    The cable pull from the shifters is what it is no matter what. Different ders make different decisions on placing the furniture with the same instructions.
    I think we're on the same page: The "instructions" are coming from the shifter-dictated cable pull/girlfriend, and the actual shifts of chain are being performed by the derailleur/boyfriend, yes?

    [Of course, IRL, the actual girlfriend is continually updating those instructions as to where the furniture is to be placed, sometimes in boyfriend's mid-lift, so the metaphor isn't perfect. ]
    More Americans wanted Hillary Clinton to be President than wanted Donald Trump.

    Donald Trump has never had a wife he didn't cheat on.

    There are over 5.2 million covid cases in the United States (as of August 12), seven months after Donald Trump said it was "totally under control," and that "it's gonna be just fine."

Similar Threads

  1. Replies: 6
    Last Post: 07-09-2013, 12:05 PM
  2. Replies: 6
    Last Post: 03-12-2013, 02:57 PM
  3. Can 10 speeds crank uses 11 speeds chain rings
    By slowoldman in forum Campagnolo
    Replies: 6
    Last Post: 05-28-2011, 08:17 AM
  4. do 9 speeds shift better than 10 speeds?
    By pdxtim in forum Components, Wrenching
    Replies: 7
    Last Post: 10-18-2007, 09:57 PM
  5. Rear derailleur compatibility, does # of speeds matter?
    By T-shirt in forum Components, Wrenching
    Replies: 6
    Last Post: 05-29-2005, 01:05 PM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  

THE SITE

ABOUT ROADBIKEREVIEW

VISIT US AT

© Copyright 2020 VerticalScope Inc. All rights reserved.