Gears won't index => new cassette?

vermin
vermin Posts: 1,739
edited April 2015 in Workshop
Quick question, as title. I have tried and tried and tried to index my 10-speed tiagra but just can't get the chain to stick on the mid-range sprockets. Is it time for a new cassette, or for a bike maintenance refresher course?
Are there any tricks I'm missing?
Ta

Comments

  • keef66
    keef66 Posts: 13,123
    Do you mean that the chain is hopping from one sprocket to the next?

    Unless you've just fitted a new one, have a look at the inner cable inside the shifter to make sure it's not fraying. That's usually what's wrong when my 105 rear shifting deteriorates and resists all attempts to index it.

    An old cassette, even when badly worn, won't affect indexing. The worn sprockets remain the same distance apart...
  • PhunkyPhil
    PhunkyPhil Posts: 143
    Maybe the mech hanger is bent.
    http://veloviewer.com/SigImage.php?a=116373&r=3&c=5&u=M&g=p&f=abcdefghij&z=a.png
  • First.Aspect
    First.Aspect Posts: 17,167
    PhunkyPhil wrote:
    Maybe the mech hanger is bent.
    Or too much play in the derailleur, or worn jockey wheels. But when tuning your shimano gears is like nailing jelly to a wall, I'd start by looking at the cable in the shifter as well. I've been caught out a few times by the cable snapping completely and stranding me in the boonies.
  • Tjgoodhew
    Tjgoodhew Posts: 628
    PhunkyPhil wrote:
    Maybe the mech hanger is bent.

    Sounds like the same problem i had and turned out to be a bent mech hanger
    Cannondale Caad8
    Canyon Aeroad 8.0

    http://www.strava.com/athletes/goodhewt
  • redvision
    redvision Posts: 2,958
    I had this exact problem on the way in to work this morning! I am also running Tiagra 10 speed.
    As far as i am aware the rear mech hanger hasn't been knocked and nothing had changed since yesterdays ride, but about 2 miles in all of a sudden the chain started jumping through the middle sprocket in both big and little rings. I stopped, checked the cable and fiddled with the rear mech barrel adjuster but it was still jumping. Then tried the barrel adjuster on the downtube (don't think i have ever touched this before) and it seemed to solve it.
    God knows why it sudden started in the first place though.

    OP, try adjusting that barrel adjuster. I know its only meant to fine tune but made the difference on mine.
  • ratsbeyfus
    ratsbeyfus Posts: 2,841
    One other possibility to check is that your freewheel isn't loose (no side-to-side movement).

    I had one of them red bikes but I don't any more. Sad face.

    @ratsbey
  • CYCLESPORT1
    CYCLESPORT1 Posts: 471
    Take it to a good local bike shop !
  • Chunky101
    Chunky101 Posts: 108
    CYCLESPORT1 wrote:
    Take it to a good local bike shop !

    With that approach you'd never learn anything.
  • kajjal
    kajjal Posts: 3,380
    If you have an old worn cassette and the gears that slip are the main ones you use while other gears seem OK it is best to get a new cassette and chain. Using an old chain on a new cassette if it has stretched too much can cause the same problem. The slipping is more obvious under power when riding the bike.

    If not then you are looking for something that is sticking, not moving properly or out of alignment.

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