Cannot eliminate front derailleur rub (FSA with Shimano with Sunrace)

benws1
benws1 Posts: 415
in Workshop
Hello.

I have a 2017 Raleigh Mustang Sport with an FSA Tempo double front ring, Shimano Claris front derailleur and a Sunrace 8 speed cassette.

I cannot eliminate front derailleur chain rub. I have tried everything according to the Shimano instructions. I have positioned the derailleur in the correct position (height over biggest ring correct and lined up the outside of the cage with the big ring teeth). I have set the cable tension so that when in the trim postion, the inner derailleur cage part is next to the chain whilst the biggest cog on the back is engaged. I have adjusted the high screw so that when the front derailleur is set to it's furthest setting, the chain is just shy of the outer bit of the cage with the smallest cog on the back selected.

I have done everything I can and the front derailleur still rubs on the top two rear cogs, rubs when you get half way down the cassette (before pushing the lever to it's furthest setting, out of the trim position), and then rubs on the smallest cog at the back. It's driving me mad.

I've been at it for hours and still get nowhere.

Does anyone think something is wrong somewhere, as in something is bent? I have noticed that when I spin the pedals the chain moves side to side a bit on the chainring when looking from above. Or is it that some components don't really match up well together (FSA chainring and Shimano derailleur, for example)?

Anyone have any ideas? I don't get how it can rub half way down the cassette when I have followed Shimano's instructions to the letter. Is the chain too big or something?

The rear derailleur is fine and doesn't have any issues.

Thanks.

Comments

  • def_defyr
    def_defyr Posts: 93
    At this point I would take it to a shop. I was having some rear derailleur issues (2x11 Campy) a few weeks ago, and finally gave up.

    35 euros, fixed, vs the several hours of my (freelance) time...

    A mechanic at a good shop sees dozens of derailleurs a week, plus set up of new bikes, so even if they can't fix it easily they can ID a bent or overly worn part quickly.
  • masjer
    masjer Posts: 2,558
    Have you set the cable alignment correctly using the plastic tool TL-FDR30? Check the cable is routed on the correct side of the clamp bolt.

    Page 13 https://si.shimano.com/pdfs/dm/DM-RBFD001-01-ENG.pdf
  • benws1
    benws1 Posts: 415
    masjer said:

    Have you set the cable alignment correctly using the plastic tool TL-FDR30? Check the cable is routed on the correct side of the clamp bolt.

    Page 13 https://si.shimano.com/pdfs/dm/DM-RBFD001-01-ENG.pdf

    No, I havent done this. I've just used the same route the bike shop setup. Saying that, I have had no end of trouble with this bike so i will get that tool and check the alignment. Thanks.
  • benws1
    benws1 Posts: 415
    def_defyr said:

    At this point I would take it to a shop. I was having some rear derailleur issues (2x11 Campy) a few weeks ago, and finally gave up.

    35 euros, fixed, vs the several hours of my (freelance) time...

    A mechanic at a good shop sees dozens of derailleurs a week, plus set up of new bikes, so even if they can't fix it easily they can ID a bent or overly worn part quickly.

    Thanks. I will see how I go with the alignment tool and take it from there. The bike shop that sold me this bike is my local one.

Categories