User Tag List

Results 1 to 11 of 11

Thread: 3x5 MTB drivetrain setup

  1. #1
    Join Date
    Nov 2019
    Posts
    9
    Post Thanks / Like
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)

    Default 3x5 MTB drivetrain setup

    Hi all

    I've just restored a 1990 Raleigh Massif, which has introduced me to the pleasures of setting up 3x drivetrains. It's all low-end Shimano stuff, not pretty but works amazingly well after 30 years (with the addition of a new chain and freewheel).

    There's one thing that puzzles me though. In the small (28T) chainring, the two largest rear sprockets (14T and 16T) cause the chain to rub against the front mech, whereas in the large (48T) chainring, I can shift through all five rear gears without any problems. This is with the limit screws set properly as per the Park Tool video (you can see I'm new to this!). I was kind of expecting the chain would rub in the largest / smallest and smallest / largest combinations.

    Have I done something wrong, or is this perhaps something to do with chainline, or just a quirk I should live with? Thanks in advance for any advice.

    Cheers

    Gareth
     

  2. #2
    Join Date
    Feb 2013
    Location
    London, UK
    Posts
    4,761
    Post Thanks / Like
    Mentioned
    4 Post(s)
    Tagged
    0 Thread(s)

    Default Re: 3x5 MTB drivetrain setup

    Perhaps you have a wrong combination of shifters and derailleurs (their pull ratio does not match)?
    The easiest solution would be to use a friction thumb-shifter or one of those cheap twist-shifter that allows you to precisely trim the derailleur. You'll be sorted with 20 bucks or less.
    Andrea "Gattonero" Cattolico, head mechanic @Condor Cycles London


    "Caron, non ti crucciare:
    vuolsi così colà dove si puote
    ciò che si vuole, e più non dimandare"

  3. #3
    Join Date
    Oct 2012
    Posts
    8,358
    Post Thanks / Like
    Mentioned
    4 Post(s)
    Tagged
    0 Thread(s)

    Default Re: 3x5 MTB drivetrain setup

    Can't you solve it by a few turns on the lower limit adjustment screw on the front mech just enough to have the clearance needed ? Or would the chain refuse to go down on the 28t chainring in that position ?
    --
    T h o m a s

  4. #4
    Join Date
    May 2008
    Location
    DC
    Posts
    24,723
    Post Thanks / Like
    Mentioned
    22 Post(s)
    Tagged
    0 Thread(s)

    Default Re: 3x5 MTB drivetrain setup

    Exactly what shifters and frame size? Also, what is your cassette range?

    My WAG is that there is nothing "wrong" per se.

  5. #5
    Join Date
    Nov 2019
    Posts
    9
    Post Thanks / Like
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)

    Default Re: 3x5 MTB drivetrain setup

    Thanks to everyone who has commented so far. Unfortunately I don't think I've explained the problem I'm having very well.

    The frame is a 19" I think. The parts involved are:

    Shimano FD-AX55 front derailleur
    Shimano RD-R552 rear derailleur (5-speed)
    Shimano SL-MY15 thumb shifters (front friction, rear indexed)
    Shimano FC-TY30 chainset (48T - 38T - 28T)
    SunRace freewheel (14T-16T-20T-24T-28T)
    SunRace 6/7-speed chain (I couldn't find a 5-speed chain)

    I can easily set the front mech low limit screw so the chain only rubs against the front mech when I'm in the 14T at the back. However, if I do this then I get slow shifts when shifting from the middle chainring to the small chainring. In order to get rapid shifts from the middle to the small ring, I have to back the low limit screw out, which causes the chain to rub against the mech in the 14T and the 16T.

    Hope this makes a bit more sense! I get that it's possible to use the friction shifter to trim the position of the derailleur, but I'm trying to make the bike as easy to use as possible for my wife.
     

  6. #6
    Join Date
    Aug 2008
    Location
    Flagstaff, Arizona
    Posts
    10,535
    Post Thanks / Like
    Mentioned
    10 Post(s)
    Tagged
    0 Thread(s)

    Default Re: 3x5 MTB drivetrain setup

    Quote Originally Posted by gmtfd View Post
    Thanks to everyone who has commented so far. Unfortunately I don't think I've explained the problem I'm having very well.

    The frame is a 19" I think. The parts involved are:

    Shimano FD-AX55 front derailleur
    Shimano RD-R552 rear derailleur (5-speed)
    Shimano SL-MY15 thumb shifters (front friction, rear indexed)
    Shimano FC-TY30 chainset (48T - 38T - 28T)
    SunRace freewheel (14T-16T-20T-24T-28T)
    SunRace 6/7-speed chain (I couldn't find a 5-speed chain)

    I can easily set the front mech low limit screw so the chain only rubs against the front mech when I'm in the 14T at the back. However, if I do this then I get slow shifts when shifting from the middle chainring to the small chainring. In order to get rapid shifts from the middle to the small ring, I have to back the low limit screw out, which causes the chain to rub against the mech in the 14T and the 16T.

    Hope this makes a bit more sense! I get that it's possible to use the friction shifter to trim the position of the derailleur, but I'm trying to make the bike as easy to use as possible for my wife.
    This here is Sheldon B territory :

    All About Front Derailers



    - Garro.
    Steve Garro, Coconino Cycles.
    Frames & Bicycles built to measure and Custom wheels
    Hecho en Flagstaff, Arizona desde 2003
    www.coconinocycles.com
    www.coconinocycles.blogspot.com

  7. #7
    Join Date
    May 2008
    Location
    DC
    Posts
    24,723
    Post Thanks / Like
    Mentioned
    22 Post(s)
    Tagged
    0 Thread(s)

    Default Re: 3x5 MTB drivetrain setup

    Quote Originally Posted by gmtfd View Post
    Thanks to everyone who has commented so far. Unfortunately I don't think I've explained the problem I'm having very well.

    The frame is a 19" I think. The parts involved are:

    Shimano FD-AX55 front derailleur
    Shimano RD-R552 rear derailleur (5-speed)
    Shimano SL-MY15 thumb shifters (front friction, rear indexed)
    Shimano FC-TY30 chainset (48T - 38T - 28T)
    SunRace freewheel (14T-16T-20T-24T-28T)
    SunRace 6/7-speed chain (I couldn't find a 5-speed chain)

    I can easily set the front mech low limit screw so the chain only rubs against the front mech when I'm in the 14T at the back. However, if I do this then I get slow shifts when shifting from the middle chainring to the small chainring. In order to get rapid shifts from the middle to the small ring, I have to back the low limit screw out, which causes the chain to rub against the mech in the 14T and the 16T.

    Hope this makes a bit more sense! I get that it's possible to use the friction shifter to trim the position of the derailleur, but I'm trying to make the bike as easy to use as possible for my wife.
    Short chainstays don't help.
    Consider shifting to one or two easier gears BEFORE you drop to the 28. That will give you a more optimal chainline.
    Ultimately this may not be solved by adjusting the front mech.
    All this assumes you have the correct bottom bracket spindle...real real likely...but for giggles you could tell me the distance from the ctr. of the center ring to the center of the seattube on a level line.

  8. #8
    Join Date
    Oct 2012
    Posts
    8,358
    Post Thanks / Like
    Mentioned
    4 Post(s)
    Tagged
    0 Thread(s)

    Default Re: 3x5 MTB drivetrain setup

    Quote Originally Posted by gmtfd View Post
    Shimano SL-MY15 thumb shifters (front friction, rear indexed)
    If the front shifter is friction I would say the whole system is designed so the user does the trimming manually. I fail to see the problem now. Looks to me it is working as intended.
    Last edited by sk_tle; 3 Weeks Ago at 03:34 AM.
    --
    T h o m a s

  9. #9
    Join Date
    Nov 2019
    Posts
    9
    Post Thanks / Like
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)

    Default Re: 3x5 MTB drivetrain setup

    Garro, thanks for the Sheldon Brown link, lots of useful info there.

    Josh, am I right in thinking you mean the chainstay length measured horizontally? If so, it's 450mm.

    Thomas, I see what you're saying. Overall the system works extremely well considering its age. I've never messed with friction shifting before so maybe it's just that my expectations are out of whack.
     

  10. #10
    Join Date
    May 2008
    Location
    DC
    Posts
    24,723
    Post Thanks / Like
    Mentioned
    22 Post(s)
    Tagged
    0 Thread(s)

    Default Re: 3x5 MTB drivetrain setup

    Quote Originally Posted by gmtfd View Post
    Garro, thanks for the Sheldon Brown link, lots of useful info there.

    Josh, am I right in thinking you mean the chainstay length measured horizontally? If so, it's 450mm.

    Thomas, I see what you're saying. Overall the system works extremely well considering its age. I've never messed with friction shifting before so maybe it's just that my expectations are out of whack.
    I stand corrected. That's a proper Chainstay.

  11. #11
    Join Date
    May 2019
    Posts
    82
    Post Thanks / Like
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)

    Default Re: 3x5 MTB drivetrain setup

    I had one of those - fastest bike I ever had (although that may be because of the skinny 16yo pedalling...)

    Mine would have been either 90 or 91 but I remember it being either 18 or 21spd - doesn’t help other than are the parts all compatible or has something been changed?
     

Similar Threads

  1. double drivetrain?
    By shrimp123 in forum General Discussion
    Replies: 15
    Last Post: 06-15-2016, 10:26 PM
  2. cleaning your drivetrain - what do you use?
    By d_douglas in forum General Discussion
    Replies: 84
    Last Post: 04-25-2016, 07:16 PM
  3. FSA electronic drivetrain
    By Tristan in forum General Discussion
    Replies: 40
    Last Post: 01-22-2015, 02:17 PM
  4. CX: Drivetrain Best Practices
    By holliscx in forum General Discussion
    Replies: 7
    Last Post: 11-23-2012, 08:59 AM

Tags for this Thread

Bookmarks

Bookmarks

Posting Permissions

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