Do I need a compact front mech?

rc856
rc856 Posts: 1,144
edited May 2011 in Road buying advice
Hi folks,

Had a compact chainset fitted today by my LBS and I've kept my 'standard' Chorus front mech.
Going through the gears at home, the front mech rubs a wee bit when I'm on the 34/29 and a couple of gears at the other extreme.
Would a compact specific front mech get rid of any rubbing in any gear or does it just go with the territory?
I'm confident my LBS would've set it up as best they could.
Cheers

Comments

  • Berk Bonebonce
    Berk Bonebonce Posts: 1,245
    What age Chorus is it? Contemporary-ish Campag front mechs are intended for both compact and standard set-ups - there are now no Campag 'compact' specific front mechs.

    But it is different with older Campag and when their front mechs came in two flavours: standard and compact.
  • nicktheluddite
    nicktheluddite Posts: 221
    Or could it be chain 'speed'? Is the original mech 9spd and the new 10spd or 11spd? I think 10 and 11spd chains are narrower (by a fraction of a mm) then 9 spd. I had trouble with this on my hybrid (although that might have been shimano 8spd vs 9spd).
  • Mister W
    Mister W Posts: 791
    The problem you have is very common with compact chainsets and more so with smaller bikes. It is to do with the angle the chain leaves the chainring and the distance from the small chainring to the front mech (which is greater on a compact than on a standard double). The solution is to adjust the mech. It should be adjusted so there is no rubbing on 34/29. You will then get more rubbing on the opposite end of the cassette but those are gears you will use less. You can also use the trim facility on the mech to allow you to use those gears without rubbing.
  • rc856
    rc856 Posts: 1,144
    Cheers folks.
    My mech is about 6yrs old. I checked it when the bike was upside down while putting the wheels back on.
    When the bike is upright, it seems ok so I was just being an a$$ :)
  • maddog 2
    maddog 2 Posts: 8,114
    what Mister W said. If you're on small-small then you should have shifted to the big ring back down the road.

    The CT mechs shift better in my experience, than the 'std' mechs.
    Facts are meaningless, you can use facts to prove anything that's remotely true! - Homer
  • Berk Bonebonce
    Berk Bonebonce Posts: 1,245
    If it's six years old it be a 'standard'.
  • Smokin Joe
    Smokin Joe Posts: 2,706
    When I first put a compact on I was using a 15 year old 105 front mech and I had no issues with shifting. I bought a Campag compact mech and it made bugger all difference.

    Marketing cobblers IMO.
  • brin
    brin Posts: 1,122
    RC856 wrote:
    Cheers folks.
    My mech is about 6yrs old. I checked it when the bike was upside down while putting the wheels back on.
    When the bike is upright, it seems ok so I was just being an a$$ :)

    now i'm going to spend all day trying to figure this out, 'bike upside down to put wheels on' :?: :?:
  • canamdad
    canamdad Posts: 165
    I use a 2001 Chorus (non compact crank) FD on one bike with 50/36 and works fine. On another have 2010 Veloce (the new one that works for compact and non) with 50/34 and it works really well too.
  • rc856
    rc856 Posts: 1,144
    Hi folks,

    Apologies for the thread resurrection....but it was mine to start with :)

    Been looking at replacing my mechs with 10sp Record (for no other reason than I want to) and shopping around for the cheapest.
    I have a Centaur CT chainset and was wondering if it makes any difference if the mechs are UT or QS as some are advertised as such.

    Many thanks :)

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