Dim front derailleur question

andywgg

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

Slow Downcp

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

wotbus@

[:)] 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

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

wotbus@

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.