Dim front derailleur question

andywgg
andywgg Posts: 303
edited June 2007 in Workshop
Took new bike out yesterday and everything was lovely - until late in the day (did about 70 miles) when what I suspect is a bit of bedding in caused chain rub in the two largest rear cogs when the chain was on the 50 tooth ring at the front. It's a 105 compact double, and I'm used to being able to trim the front mech on my other campag bike.

There hadn't been any rub (tiny bit on the largest/largest combo but I can live with that) but with a double I want to be able to use most of the gears without having to go down to the small ring.

Here's the dim bit: I'm assuming there's some slight adjustment I can make as I suspect this is just a bit of new cable stretch - but where do I do it?

Told you it was daft...

Ta

may the dawes be with you...

andy
may the dawes be with you...

andy

Comments

  • Slow Downcp
    Slow Downcp Posts: 3,041
    You shouldn't really use the two biggest rear sprockets whilst in the large chainring - it causes the chain into an unnatural angle and wears quicker.

    Carlsberg don't make cycle clothing, but if they did it would probably still not be as good as Assos
    Carlsberg don't make cycle clothing, but if they did it would probably still not be as good as Assos
  • wotbus@
    wotbus@ Posts: 301
    [:)] There's actually 3 clicks on the 105 - are you using them all? You may be under the impression because there are only two rings there are only two positions.
  • andywgg
    andywgg Posts: 303
    I know about chain angle and stuff, SD, but running a double (I thought) was meant to mean the chain angles aren't too extreme so you can use most of the range. Anyway - it was running fine on large front and 2nd to largest back for most of the day then by the end it wasn't - which suggests something had gone slightly out of adjustment. I just need to know what it is.

    And thanks too, wotbus - I think I know about the 'half click' trim adjustment on shimano (if it is that of which you speak) but I did try and before the rub stopped the chain moved onto the small ring with the usual spinny consequences!

    may the dawes be with you...

    andy
    may the dawes be with you...

    andy
  • wotbus@
    wotbus@ Posts: 301
    Don't worry too much about the big/big thing. I have 10sp 105 compact and stayed on the 50 all the time, with the odd spell on big/big for really steepies. I found the only way I could trim out the bit of chain rub is to drop onto the inner then straight away move the lever one click up (middle position?). I couldn't find this trim position changing the other way EG: move the little lever and it will drop all the way to the inner. These compact thingies are a bit of a compromise all round but they have their uses and followers [;)]. I have since changed the 34 for a 39 and wish I had discovered the 50/39 combo years ago...
    As your bike is new, leave it a while for it all to settle in then you may be able to achieve what you want with a bit of tweaking of the mech position rather than cable or the more usual adjustments.

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