Sora and high limit adjustment on front derailleur

lotus49
lotus49 Posts: 763
edited January 2013 in Workshop
When my chain is on the big gear at the front and the smallest couple of gears at the back the right hand side of the chain rubs against the inside of the derailleur cage. When I tried to adjust the high limit, the screw was already fully loosened so the cage will not move any further out.

Is this likely to be because my whole front derailleur is not correctly positioned? The derailleur looks to be at the right height and is parallel to the crankset. It looks spot on when on the small gear at the front and the big gear at the back.

Comments

  • cycleclinic
    cycleclinic Posts: 6,865
    Have you tried pushing the shift paddle more?
    http://www.thecycleclinic.co.uk -wheel building and other stuff.
  • sturmey
    sturmey Posts: 964
    Sounds like too much cable tension in front mech cable.The mech cage won't move out any further cos the already max stretched cable won't let it.
  • seagullsfan
    seagullsfan Posts: 3
    This has happended to mine a couple of times since i purchased my bike back in September. Sturmey is correct, the cable tension must have slackened a little. This first happended to mine after a few weeks of riding. I just put it onto the smallest cog on the crank and then increased the cable tension. This worked for me, also saved me a trip to my LBS.
  • lotus49
    lotus49 Posts: 763
    thecycleclinic wrote:
    Have you tried pushing the shift paddle more?

    I have but if I push it any more, it will snap off. The bike (Giant Defy 3) came from Halfords and they appear to have used their customary care when assembling it. Until I had a go at adjusting it myself, it wouldn't even shift onto the big cog, principally because the derailleur was nothing like parallel to the plane of the crank. Now it does but it rubs although only when on the smallest rear cogs.
    sturmey wrote:
    Sounds like too much cable tension in front mech cable.The mech cage won't move out any further cos the already max stretched cable won't let it.
    seagullsfan wrote:
    This has happended to mine a couple of times since i purchased my bike back in September. Sturmey is correct, the cable tension must have slackened a little. This first happended to mine after a few weeks of riding. I just put it onto the smallest cog on the crank and then increased the cable tension. This worked for me, also saved me a trip to my LBS.

    I'm a little confused between your two answers. Do you mean that the cable is too tight (which is what sturmey seems to be saying) or not tight enough (which is what seagullsfan seems to be saying).

    I did disconnect the derailleur cable completely from the front mech when the chain was on small/big and pull it finger tight before reattaching it. I'll have a play around with it but I'd appreciate any further advice.
  • lotus49
    lotus49 Posts: 763
    After a bit of fiddling around with the cable and readjusting the stops it now seems to be more or less right. The mech does feel a little stiff so I suspect a bit of lubrication might not go amiss. I have a tin of GT85 so I presume giving it a little spray of that will do the trick.

    I'll see if I can nip out on it after I've put my children to bed and give it a proper test.

    Thanks for your help.
  • smidsy
    smidsy Posts: 5,273
    Not enough tension which restricts the movement so no amount of twiddling with the H screw helps.
    Yellow is the new Black.
  • seagullsfan
    seagullsfan Posts: 3
    We have the same bike. Is it a 2013? I have suffered from a loss of tension, so loosing the bolt and increasing the tension solved my problem, as I was getting chain rub on the large ring. I did not have to touch H screws. However, this has happened to me twice over a six week period so i am worried it will reoccur.
  • lotus49
    lotus49 Posts: 763
    seagullsfan wrote:
    We have the same bike. Is it a 2013? I have suffered from a loss of tension, so loosing the bolt and increasing the tension solved my problem, as I was getting chain rub on the large ring. I did not have to touch H screws. However, this has happened to me twice over a six week period so i am worried it will reoccur.

    Indeed it is.

    It may well be that I didn't need to touch the stop adjustment screws either but that only became apparent once I had tried and it didn't work. We have had the same problem but it may just be that the cables stretch a bit from new. I can't say I am too worried. I carry a multitool around with me and if that is all that's wrong, it's pretty easy to fix.

    So far the rear derailleur has been faultless. Unfortunately I am probably not going to be able to go for a proper ride until the weekend now but I'll see if I can nip out tomorrow and check whether I have really fixed the problem.
  • buckmulligan
    buckmulligan Posts: 1,031
    For the record, most frames will have barrel adjusters as part of the cable stops on the down tube. These allow you to adjust the cable tension without having to undo the cable from the mech and will give you much finer adjustment. Simply stick the chain on the little ring and you should be screw the barrel adjuster out a bit to take up some of the cable slack. You shouldn't have to touch the limit screws on the front or the rear mech if it's been set up properly to start with.

    Most new bikes suffer from cable stretch in the first couple of months, because most manufacturers use cheapo cables when building them. It should settle down after a while, but if it keeps happening, try replacing the inner cables with some decent ones.

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