Advertise on Bikeforums.net



User Tag List

Results 1 to 13 of 13
  1. #1
    Senior Member spectastic's Avatar
    Join Date
    Aug 2012
    Location
    undisclosed
    My Bikes
    road bikes
    Posts
    1,988
    Mentioned
    8 Post(s)
    Tagged
    0 Thread(s)

    how did my cable tension increase all of a sudden?

    When I tuned up the RD two weeks ago, it was 60 degrees F. Today, it was 40. I noticed the up shifts were instantaneous, but the down shifts were noticeably more cumbersome. Sometimes it was smooth, but other times, the chain would just rub the sprocket, and not budge unless I shift it twice. I thought that this could only mean that the cable tension increased. But then again, 20 degrees F is nothing... Is adjusting cable tension a common practice when it comes to index shifters?

  2. #2
    bike whisperer Kimmo's Avatar
    Join Date
    Dec 2009
    Location
    Melbourne, Oz
    My Bikes
    copy/paste links: http://velospace.org/node/36949 http://velospace.org/node/47746 http://velospace.org/node/47747
    Posts
    6,842
    Mentioned
    10 Post(s)
    Tagged
    0 Thread(s)
    Hm... could be the 20F.

    Shimano 10spd?

  3. #3
    Senior Member spectastic's Avatar
    Join Date
    Aug 2012
    Location
    undisclosed
    My Bikes
    road bikes
    Posts
    1,988
    Mentioned
    8 Post(s)
    Tagged
    0 Thread(s)
    40, not 20; I meant to say 20 degrees F difference between 40 and 60. and yes. ultegra 6700

    why, does the manufacture matter?

  4. #4
    Senior Member Bill Kapaun's Avatar
    Join Date
    Feb 2007
    Location
    Mid Willamette Valley, Orygun
    My Bikes
    86 RockHopper,2008 Specialized Globe. Both upgraded to 9 speeds.
    Posts
    7,382
    Mentioned
    4 Post(s)
    Tagged
    0 Thread(s)
    Easier up shifts means the cable is looser.
    Maybe your "tune up" was lacking and things simply "settled in"?

  5. #5
    bike whisperer Kimmo's Avatar
    Join Date
    Dec 2009
    Location
    Melbourne, Oz
    My Bikes
    copy/paste links: http://velospace.org/node/36949 http://velospace.org/node/47746 http://velospace.org/node/47747
    Posts
    6,842
    Mentioned
    10 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by spectastic View Post
    40, not 20; I meant to say 20 degrees F difference between 40 and 60. and yes. ultegra 6700

    why, does the manufacture matter?
    I meant Δ20F.

    Cable pull per shift varies by manufacturer and number of speeds; Shimano's 10spd uses the shortest cable pull yet, an average of 2.3mm. This minimises signal-to-noise, obviously.

  6. #6
    Mechanic/Tourist
    Join Date
    Apr 2007
    Location
    Syracuse, NY
    My Bikes
    2008 Novara Randonee - love it. Would have more bikes if I had time to ride them all. Previous bikes: 1968 Motobecane Mirage, 1972 Moto Grand Jubilee (my fav), Jackson Rake 16, 1983 C'dale ST500.
    Posts
    5,373
    Mentioned
    8 Post(s)
    Tagged
    0 Thread(s)
    Some people call going to larger rear cogs upshifts, some call going to higher gears ratios upshifts. It's helpful to state which you mean. If by upshift you mean a higher gear ratio (smaller cog) then it is likely that there is excess friction in the cable/housing or less likely in the lever mechanism, which could be caused by the colder weather or by contamination from the poorer weather if you ride on wet streets. Put the bike in a stand and shift to the largest cog. Stop the wheel and shift the lever all the way to the small cog (most relaxed cable) position. Move the cable in each section of housing back and forth to find the source of friction. If one lubricates cables (not necessary for lined housing and stainless cables) one should never use grease unless working with old-fashioned unlined housing, as it will often thicken with time, temp, etc. Use Phil or other good quality oil or "wet" chain lube.
    Last edited by cny-bikeman; 11-03-12 at 04:48 PM.
    There's no such thing as a routine repair.

    Don't tell me what "should" be - either it is, it isn't, or do something about it.

    If you think I'm being blunt take it as a compliment - if I thought you were too weak to handle the truth or a strong opinion I would not bother.

    Please take the time to post clearly so we can answer quickly. All lowercase and multiple typos makes for a hard read. Thanks!

  7. #7
    Senior Member spectastic's Avatar
    Join Date
    Aug 2012
    Location
    undisclosed
    My Bikes
    road bikes
    Posts
    1,988
    Mentioned
    8 Post(s)
    Tagged
    0 Thread(s)
    up shift = going to larger sprocket.

  8. #8
    rebmeM roineS JanMM's Avatar
    Join Date
    Jan 2006
    Location
    Indiana
    My Bikes
    RANS V3, RANS V-Rex, RANS Screamer
    Posts
    11,854
    Mentioned
    2 Post(s)
    Tagged
    0 Thread(s)
    up shift = going to a higher gear
    RANS V3 (steel), RANS V-Rex, RANS Screamer

  9. #9
    Senior Member Retro Grouch's Avatar
    Join Date
    Feb 2004
    Location
    St Peters, Missouri
    My Bikes
    Rans Enduro Sport, Hase Kettweisel Tandem, Merin Bear Valley beater bike
    Posts
    24,010
    Mentioned
    1 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by spectastic View Post
    up shift = going to larger sprocket.
    In that case, your cable housing ends have probably just seated in the cable stops. tighten the cable tension a tad and you'll be good-to-go for a long time.

  10. #10
    Senior Member
    Join Date
    Jul 2011
    Location
    Minneapolis, MN
    My Bikes
    Trek Allant
    Posts
    163
    Mentioned
    1 Post(s)
    Tagged
    0 Thread(s)
    Exact same thing happened recently to me, and I fixed it by tightening the cable. Same deal a week later. Then the cable broke right at the shifter. So make sure the cable isn't getting longer because it is fraying, not just stretching, in a place you can't see well, like in a shifter housing.

  11. #11
    Senior Member
    Join Date
    Nov 2008
    Location
    Bay Area, Calif.
    Posts
    5,052
    Mentioned
    5 Post(s)
    Tagged
    0 Thread(s)
    I suspect the issue isn't with the cable tension or adjustment, but with the colder temperature creating greater friction inside the cable housing. If the cable is greased a lower temperature may have made the grease much thicker making the cable move more sluggishly or even binding.

  12. #12
    Mechanic/Tourist
    Join Date
    Apr 2007
    Location
    Syracuse, NY
    My Bikes
    2008 Novara Randonee - love it. Would have more bikes if I had time to ride them all. Previous bikes: 1968 Motobecane Mirage, 1972 Moto Grand Jubilee (my fav), Jackson Rake 16, 1983 C'dale ST500.
    Posts
    5,373
    Mentioned
    8 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by spectastic View Post
    up shift = going to larger sprocket.
    Well, as you were speaking of the rear derailleur we will assume you mean larger cogs - convention is generally to call the rear parts of a freewheel/cassette cogs and the front chainrings/chainwheels/sprockets.

    Quote Originally Posted by Retro Grouch View Post
    In that case, your cable housing ends have probably just seated in the cable stops. tighten the cable tension a tad and you'll be good-to-go for a long time.
    Not correct - that would not make for noise, partial shifts but it would be consistent. The OP describes sometimes shifting, sometimes not.

    Quote Originally Posted by prathmann View Post
    I suspect the issue isn't with the cable tension or adjustment, but with the colder temperature creating greater friction inside the cable housing. If the cable is greased a lower temperature may have made the grease much thicker making the cable move more sluggishly or even binding.
    Correct, as I explained earlier.
    Last edited by cny-bikeman; 11-03-12 at 04:46 PM.
    There's no such thing as a routine repair.

    Don't tell me what "should" be - either it is, it isn't, or do something about it.

    If you think I'm being blunt take it as a compliment - if I thought you were too weak to handle the truth or a strong opinion I would not bother.

    Please take the time to post clearly so we can answer quickly. All lowercase and multiple typos makes for a hard read. Thanks!

  13. #13
    Senior Member spectastic's Avatar
    Join Date
    Aug 2012
    Location
    undisclosed
    My Bikes
    road bikes
    Posts
    1,988
    Mentioned
    8 Post(s)
    Tagged
    0 Thread(s)
    so this whole time I've been working with a bent hanger. This is a commonly sited problem for BD bikes, and I had my suspicions when putting it together. The RD just didn't look right from the beginning, but I didn't think much of it because everything was working nicely. Good thing they had a spare hanger in the box.

    Now it's all good. There's some really small clicking noise on certain gearing combinations, but I'm assuming that's just part of the drive chain - nothing out of the ordinary.

Posting Permissions

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