Gears Jumping

slinkydonkey
slinkydonkey Posts: 27
edited May 2017 in Workshop
Hello All

I have a 2013 GIANT Defy compact 3, the gears have been jumping a lot particularly when in low gears and on hills.
I would usually take my bike to a shop but i want to learn to do it my self.

I bought a chain wear tool and I can confirm my chain is not stretched to the 1.0 or .75 markings.
How are you supposed to check if it's the cassette that is warn?

Could it be cables which are stretched causing it to jump?
For the sack of £20 should I just replace the chain and cassette anyway?

Cheers
Paul

Comments

  • slinkydonkey
    slinkydonkey Posts: 27
    I measured it will a ruler and it is stretched to 12 Inches 2/16 of an inch it also looks a bit rusty so will change it.
    I have a replacement KMC which is the same one which is on the bike.

    However to think of it I would prefer a chain which has a magic link so i can replace the chain if I had too whilst on the road.

    Would a KMC Z8 be better?

    Cheers
    Paul
  • dj58
    dj58 Posts: 2,222
    Watch these GCN videos
    https://www.youtube.com/watch?v=Bbk5RcH0bbQ
    https://www.youtube.com/watch?v=621wu4-SXUs
    https://www.youtube.com/watch?v=-7ea5tpiM7I
  • father_jack
    father_jack Posts: 3,509
    Could be one or more of the following, so go through each.

    1) Chain is worn
    2) Cassette is worn
    3) Indexing isn't right
    4) Mech hanger is bent
    5) Deralleur is mis-aligned/bent
    6) Chain is too long
    Say... That's a nice bike..
    Trax T700 with Lew Racing Pro VT-1 ;-)
  • bobmcstuff
    bobmcstuff Posts: 11,400
    Father Jack wrote:
    Could be one or more of the following, so go through each.

    1) Chain is worn
    2) Cassette is worn
    3) Indexing isn't right
    4) Mech hanger is bent
    5) Deralleur is mis-aligned/bent
    6) Chain is too long
    7) Cassette has come loose :)

    Just happened to me - also manifests with a lot of creaking...
  • slinkydonkey
    slinkydonkey Posts: 27
    Thanks guys lots for me to test :)
  • dj58
    dj58 Posts: 2,222
    slinkydonkey wrote:
    I measured it will a ruler and it is stretched to 12 Inches 2/16 of an inch it also looks a bit rusty so will change it.
    I have a replacement KMC which is the same one which is on the bike.

    However to think of it I would prefer a chain which has a magic link so i can replace the chain if I had too whilst on the road.

    Would a KMC Z8 be better?

    Cheers
    Paul

    Giant Spec. quotes you bike as having 9 speed transmission, so a KMC X9-93 comes fitted with a missing link
    http://www.halfords.com/cycling/bike-pa ... -116-links
  • Bobbinogs
    Bobbinogs Posts: 4,841
    You can also add freehub and/or bearing play into the mix. Took me a little while to work out a loose freehub as the cause of some recent skipping. Once correctly diagnosed it took about 2 minutes to fix.

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