Chain rub NIGHTMARE!

togg
togg Posts: 80
edited August 2011 in Road beginners
I've only had my boardman team carbon about 1 month and it's never really run smoothly, the chain rub on the gears is driving me crazy, Halfords have looked at it about 6 times and it's doing me head in.

I'm new to road cycling and love it but this is killing me, when it's in the large cog and I'm pedalling fast the last 3 gears are all grinding and making noise, is this normal, I'll be taking it to my LBS soon because I don't trust Halfords ability at all.

Comments

  • Daerve
    Daerve Posts: 33
    No it's not normal, the gears should be indexing smoothly and quietly.

    Personally I'd keep hassling Halfords till they fix it properly. If we all bypassed them and went to the LBS they'll never learn to do a proper job.
  • furrag
    furrag Posts: 481
    Don't take it anywhere - learn to do it yourself. It'll save you so much hassle! If you're really fixed on taking it to your LBS, then you have nothing to lose by giving it a go yourself! Plenty of videos on youtube for setting up your front derailleur.

    When you say large cog, I assume this is on the front (chainset), and not the back (the cassette on the wheel)?

    It sounds like your front derailleur high limit screw needs adjusting. Beware that too much adjustment will then have your chain rubbing when in your biggest sprockets on the cassette, so it's about finding a good equilibrium.
  • togg
    togg Posts: 80
    Yes it's the large cog at the front and smallest cogs at the back when it starts to rub, it's strange because it doesn't start to act up until I've done about 10-15mile after Halfords have looked at it, I was thinking of just twiddling about with the limit screws but I suppose the problem would just appear again when I was climbing hills, it's so annoying.
  • jgsi
    jgsi Posts: 5,062
    togg wrote:
    Yes it's the large cog at the front and smallest cogs at the back when it starts to rub, it's strange because it doesn't start to act up until I've done about 10-15mile after Halfords have looked at it, I was thinking of just twiddling about with the limit screws but I suppose the problem would just appear again when I was climbing hills, it's so annoying.
    YOu dont need to do any miles on it to show up badly set gears.
    When it's on the workstand( yes it is best to have one of those), put the chain on the big front ring and small back ring..... turning the pedals... should be no noise.. as you go up the cassette it is normal for the larger back sprockets to rub a bit.. depending on your mech...
    my Ultegra does this , but not Sora. All mechs have their individualities
    Its a compromise as really should have shifted to small front ring.
    Small front ring and larger rear sprockets - noiseless - as you go down the gears, then you'll get chain rub again.
    Restting the rear and front mechs is probably 2 or 3 out of 5 for complexity fairly easy in other words - there are resources on the web to use - Park Tools for example.
    Workstand ( squatting down and lifting the back wheel to adjust a mech is no FUN) and a few basic tools is what you need.
    Well that me good deed for the day, thank you
  • jonni3
    jonni3 Posts: 57
    If you fancy giving it a go for yourself there's a pretty decent video work shop on bikeradar showing how to.
    Fuji team 1.0
  • togg
    togg Posts: 80
    It puzzles me because it runs perfectly fine on the work stand when Halfords sort it out, then when I get my hands on it and start using it all the fine tuning seems to come undone.

    Could it be my poor technique when shifting from the small ring at the front to the large ring? Or something that's been adjusted gradually coming loose
  • anto164
    anto164 Posts: 3,500
    Quick question, I don't know SRAM (I'm guessing it's sram as it's a boardman), but are you using the trim function when in the big ring?

    I'm presuming the rub is the front mech.
  • dennisn
    dennisn Posts: 10,601
    anto164 wrote:
    Quick question, I don't know SRAM (I'm guessing it's sram as it's a boardman), but are you using the trim function when in the big ring?

    I'm presuming the rub is the front mech.

    Well put. I'm going to vote for not trimming the front mech while riding. This would do it every time if you don't know what you're doing or what trimming is.
  • togg
    togg Posts: 80
    Not sure what trimming is to be honest or if I'm doing it by mistake? This is my bikes spec
    http://www.boardmanbikes.com/road/road_team_carbon.html

    Is it possible I could untrim? And stop this horrible rubbing
  • sungod
    sungod Posts: 17,348
    link says you've got shimano 105, this pdf explains how the shifters work and explains trimming...

    http://techdocs.shimano.com/media/techd ... 702880.pdf
    my bike - faster than god's and twice as shiny
  • jgsi
    jgsi Posts: 5,062
    togg wrote:
    Not sure what trimming is to be honest or if I'm doing it by mistake? This is my bikes spec
    http://www.boardmanbikes.com/road/road_team_carbon.html

    Is it possible I could untrim? And stop this horrible rubbing

    Trim is the left hander front mech shifter making clicks to make smaller movements of the front mech to get rid of chain rub.
    I big click to shift from big to small, then maybe another little click to get the mech away from the chain
  • 5tu-pid
    5tu-pid Posts: 22
    Hi Togg

    I had exactly the same problem with my Boardman Road and ended up taking it back 3 times to get resolved.

    I complained to the manager as each time I took it back it was a 30 mile round trip and they offered my 40p per mile to cover this, so I ended up with a £36 credit to spend in store.
    '96 Kona U'hu
    '11 Specialized Camber Expert
    '11 Boardman Road Race
  • togg
    togg Posts: 80
    Did they fix it in the end? And what was the problem, I might complain to trading standards next and see if that sharpens them up
  • jonni3
    jonni3 Posts: 57
    Togg, it could be due to cable stretch it's a month old bike & the cables do need a few weeks to bed in.

    It's the same story as yours (without the visits to retailer) with my Fuji running the exact same drivetrain as yours, it'll be 6 weeks old in a few days & time for it's gear, brake adjustments & re-torquing work over.
    Fuji team 1.0
  • togg
    togg Posts: 80
    Had a look out on the bike earlier and tried "trimming" it certainly reduced the chain rub noise when in the large front cog and smaller rear cogs, then I managed to undo my good work again, still not sure what I'm supposed to be doing.

    I'm beginning to think it's me not shifting properly and I've caused the chain to rub by poor shifting. I can hear the clicks when I'm attempting to trim.

    Just to recap i never use the small front cog and small rear gears, and I never use the large front cog and large rear gears...which according to the instructions would cause chain rub, that makes sense because of the angle the chain is running at.

    Which is the best way to trim to stop this chain rub when I'm in large front cog and small rear gears?
  • John.T
    John.T Posts: 3,698
    If the chain is rubbing on the mech cage in these gears then either the cable is too slack or the limit screw is too tight. Most likely the former. Try using the cable adjuster that should be either on the down tube or in-line on the cable. You need to lengthen the effective length of the outer cable.
    The Trim facility will not help with this as it only lets the mech move back a little to stop rub on the inside of the cage when using big ring and the larger sprockets. It works the opposite way when on the small ring for the smaller sprockets.
    My Fleet.

Categories