Forum home Road cycling forum Workshop

Chainset rings wobble

Father JackFather Jack Posts: 3,508
edited August 2010 in Workshop
When I spin the pedals, the chainset rings wobble slightly. The BB is fine, not loose, and the chainset is fitted to the BB axle properly. Is it likely the BB axle or chainrings/chainset is bent slightly causing this wobble? What happens is the chain rubs against the front derailler on certain gears, more so than my other Campag equipped bike. I have spent ages fiddling with indexing and no avail it is not as smooth as the other bike. I might pickup another chainset, useful to have a spare anyway. Or maybe I could convert it to double? It's a triple bike, so guess need new BB and of course double chainset. I guess front derailler will need to be adjusted but that will only require end stops to be changed?

I could try taking off the triple and bb off my good bike and trying it out on the bad one...if it still wobbles then possibly frame on the BB is out :-(

Campagnolo Mirage triple 53/42/30T

seem to have problems finding exactly the same one.
Say... That's a nice bike..
Trax T700 with Lew Racing Pro VT-1 ;-)

Posts

  • rakerake Posts: 3,281
    my sora chainset does it a little . may be bad luck slightly untrue crank. im very impressed with the sram s350 it arrow straight maybe why its better quality. i dont think its the bb.
  • sungodsungod Posts: 12,202
    do all rings wobble? if not, probably a slightly bent ring - you can straighten it

    does the right crank arm wobble too? if not, bent spider - probably you can straighten it

    if one/both crank arms wobble, bent axle or something amiss with the bb - unlikely you could straighten it
    my bike - faster than god's and twice as shiny
  • Father JackFather Jack Posts: 3,508
    ok I have removed both crank arms, chainset (removed each ring too) need to remove BB. Noticed it's different to my other campag BB tool :( so need another BB tool

    bb.jpg
    Say... That's a nice bike..
    Trax T700 with Lew Racing Pro VT-1 ;-)
  • Father JackFather Jack Posts: 3,508
    ok I have removed both crank arms, chainset (removed each ring too) need to remove BB. Noticed it's different to my other campag BB tool :( so need another BB tool

    bb.jpg
    Say... That's a nice bike..
    Trax T700 with Lew Racing Pro VT-1 ;-)
  • Weejie54Weejie54 Posts: 750
    Noticed it's different to my other campag BB tool

    That's because it is a Kinex BB. You need a Shimano removal tool.
  • jgsijgsi Posts: 5,025
    Square taper....
    The one I had was prone to the 'wobble' after replacing the crankset.
    I was just extra carefull in 'knocking on' the cranks especially the drive side when replacing and tightening progressively and again carefully to the right torque.
    If the BB is old then replace - it's a cartridge type? so very easy to do oneself.
    If you going down to a double then you can reduce width of that BB to 108 for instance.
    Maybe think of upgrading to ISIS type.... ?
  • Father JackFather Jack Posts: 3,508
    What's the benefit of ISIS? My other bike has centaur bb with this type of removal socket
    http://www.wiggle.co.uk/p/cycle/7/Cyclu ... 5360041221
    Say... That's a nice bike..
    Trax T700 with Lew Racing Pro VT-1 ;-)
  • jgsijgsi Posts: 5,025
    ISIS designed to be stronger and longer lasting - well that was the design blurb.
    Still a stepup from square taper.
  • Father JackFather Jack Posts: 3,508
    Say... That's a nice bike..
    Trax T700 with Lew Racing Pro VT-1 ;-)
  • Father JackFather Jack Posts: 3,508
    woo removing chainset and chain rings has fixed the problem, chain rub has gone and so has the wobble. Perhaps the fixing bolts on the chainring were not put on equally and rings were bent one way a little? Need a proper ride but just gone up the street and so far so good.
    Say... That's a nice bike..
    Trax T700 with Lew Racing Pro VT-1 ;-)
Sign In or Register to comment.