Gear shifting problems

willow71uk
willow71uk Posts: 114
edited February 2014 in Workshop
I'm having some problems shifting gears on my Shimano Tiagra rear derailleur. I have adjusted the indexing by turning half turn etc but just can't them to shift properly. The bike has done 5500 miles would it be best to just replace the cables? If i get new cables do you really need to buy the expensive cutters for the cable/housing wouldn't just bog standard electrical cutters do the trick?

Comments

  • majormantra
    majormantra Posts: 2,094
    Probably not a bad idea to recable anyway, but there are other possible reasons (e.g. bent hanger) for bad shifting.

    You do need a decent set of cutters that's capable of cutting hard, braided and wound cables, which basic snips will struggle with. You can find them online for around a tenner.
  • willow71uk
    willow71uk Posts: 114
    Bent hanger is something i have checked and it has had a new cassette and chain just before xmas. Think i will replace the cables and see if that helps. Mystify's me why tools for bikes are so expensive for something you might use once or twice.
  • freezing77
    freezing77 Posts: 731
    willow71uk wrote:
    I'm having some problems shifting gears on my Shimano Tiagra rear derailleur. I have adjusted the indexing by turning half turn etc but just can't them to shift properly. The bike has done 5500 miles would it be best to just replace the cables? If i get new cables do you really need to buy the expensive cutters for the cable/housing wouldn't just bog standard electrical cutters do the trick?

    It what way does it not shift correctly?
  • willow71uk
    willow71uk Posts: 114
    Very slow shifting up or down sometimes not shifting at all, and that's after i have spent ages adjusting the indexing turning bit by bit.
  • keef66
    keef66 Posts: 13,123
    Unless the rear mech is really badly gunked up I'd say that sounds like a cable problem. Don't scrimp on the cable cutters and make sure the cut ends are nicely cleaned up, perfectly square and not squashed at all. If you're re-cabling the gears including re-wrapping the bar tape it makes sense to do the brakes at the same time. A complete cable kit like the Jagwire Racer set then makes sense. Other brands are available :D
  • freezing77
    freezing77 Posts: 731
    Is the derailleur free to move?
    Is the "b" screw set correctly?
    Are the cables free in the housings?
    Are the STI's sufficiently lubricated.
    etc.etc.

    To check these you can remove the cable and manually move the derailleur to check freedom of movement. If not free lubricate the pivots.
    To check the "b" screw adjustment look here
    http://sheldonbrown.com/derailer-adjustment.html
  • willow71uk
    willow71uk Posts: 114
    I will check all that freezing77 before buying cables. I have OCD so my bike is sparkly clean :)
  • Millidog
    Millidog Posts: 32
    Try removing cables from outers and clean out using GT85. If this does not work replace cables. You must use a proper cable cutter !! Best check if everything is lined up properly ie hanger, cage etc. as well. Tiagra stuff is pretty good and lasts well but if you are going to replace then I suggest 105 or Ultegra (JE James have some good prices at the moment)

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