Centaur Rear Shifting Problem

starockets
starockets Posts: 67
edited March 2011 in Workshop
I am having real problems shifting around the middle gears on my Centaur rear cassette.
I have adjusted and re-adjusted without any success, I still have to over shift and then drop back down to get it into the gear I am after.

Am I looking at getting a better cassette or does anyone have any tricks of the trade to get it working properly?

Comments

  • Monty Dog
    Monty Dog Posts: 20,614
    Don't change anything until you've cleaned/lubed or replaced your cables
    Make mine an Italian, with Campagnolo on the side..
  • Monty Dog wrote:
    Don't change anything until you've cleaned/lubed or replaced your cables

    I've lubed up the cables again and had a look at them, they all seem fine. The bike only has about 500 miles on it which is why I am thinking it is an iffy cassette.
  • keef66
    keef66 Posts: 13,123
    has the cable been reattached to the rear mech at any time? If so, is it routed correctly?
  • The only time it has been reattached is when I set it up again.

    Gears 1,2,3,4 & 7,8,9,10 run spot on, 5 & 6 are the annoying ones.
    I've put more tension on the cable then removed it and it still has minimal effect in both instances ( 1/4 turn at a time ).

    I'm getting used to riding with it but I have never had this problem with Shimano and I'm refusing to let it get the better of me just because it's Campag.
  • Monty Dog
    Monty Dog Posts: 20,614
    Just to confirm, the indexing was working fine from new? There's no reason why it would go out of adjustment / wear in such a short period of time - a new cassette probably won't change anything because it's the shifters / cable pull that dictate the movement of the rear mech. Check that the rear mech hasn' taken a knock or gone out of alignment. Try following the Campagnolo instructions to indexing, setting up from middle-sprockets i.e. 5 or 6 and see if that makes a difference?
    Make mine an Italian, with Campagnolo on the side..
  • Monty Dog wrote:
    Just to confirm, the indexing was working fine from new?

    It has never worked properly at all. I got the bike in October last year and it was like it then straight out of the box. I went with it so the cables could stretch out a bit and then I was going to readjust everything.

    The mech appears to be straight and in good order, so it looks like i'll go with what you have advised and go back to basics again with the manual.

    It isn't stopping me riding but it is just annoying having to go past the gear to then drop back into the one I want.
  • Berk Bonebonce
    Berk Bonebonce Posts: 1,245
    1/ Have you shortened the outer cable run at the end of the chainstay and where it goes into the rear mech? Don't ever shorten this piece of outer cable.

    2/ Do not pull the cable mega tight when you clamp it at the rear mech. Steady pull with ordinary pliers.

    3/ Do not over-turn adjustment screw at rear mech. Quarter turn at a time type of thing.
  • red dragon
    red dragon Posts: 263
    I have had a similar problem, which went on for a good 6 months. I had got to the point where I was going to change it. But I upgraded the wheels and had a new cassette and chain. Then my LBS adjusted the set up and I got it back, and it has been working great since then. By all acounts adjustment is by little tweeks only.
  • I'm giving it another go tonight, I've done this numerous times but this is beating me at the moment. Fresh mind tonight and some good advice should see it sorted :?

    Thank you everyone for replying.
  • starockets wrote:
    I'm giving it another go tonight, I've done this numerous times but this is beating me at the moment. Fresh mind tonight and some good advice should see it sorted :?

    Thank you everyone for replying.

    Is the cassette tightened?
  • You could try checking the spacing of the sprockets. Use a steel rule or (better) dismantle the cassette and measure the thickness of all the spacers and sprockets using vernier calipers or a micrometer. They should all be the same. You could also check the lifting ramps on the offending sprokets and/or individual teeth for damage.

    If this has always been a problem then the cassette is not fit for purpose and should be replaced for free. See your bike shop
  • Monty Dog
    Monty Dog Posts: 20,614
    If it hasn't worked since new, then there is chance that the spacers in the cassette have been fitted incorrectly - there are two thicknesses of spacer on the Centaur cassette - I dropped one once and it took me a while to work out why it wasn't shifting correctly. Generally, if you can get gears to index 1-2-3 correctly then there's no reason why it shouldn't work across all the sprockets.
    Make mine an Italian, with Campagnolo on the side..
  • Monty Dog, stigofthedump, i've just ordered up a cassette tool so will give it a go in a couple of days when it turns up. Only have Shimano stuff at the moment.
  • stoobydale
    stoobydale Posts: 535
    You could try checking the spacing of the sprockets. Use a steel rule or (better) dismantle the cassette and measure the thickness of all the spacers and sprockets using vernier calipers or a micrometer. They should all be the same

    Not sure this is 100% true. Check out the Campag website for exploded views of the cassettes. If it hasn't worked from new and the cable routing is ok get the LBS to check that the hanger isn't bent.