Front deraillier cable adjustment using adjuster barrel

[Fifelad]

All gears are changing fine but on small ring at front and two biggest rings at the back I have chain rub on the front deraillier cage, that a fine adjustment with the cable barrel adjustment should sort I think. Remind me what way to turn the adjuster so that the cage is moving away from the chain ie to the left as looking from behind or closer to the frame of the bike. Thanks.

 

[Pauluk]

If your gears are changing ok then your cable tension is probably set correctly, so no need to touch the barrel adjuster. Sounds like the low limit screw on the front derailleur needs adjusting slightly to move the cage inward to avoid the cage rub. Don't go too far though otherwise the chain may come off when you change down.

 

[Fifelad]

I was loathe to do this as I have just adjusted the limit screw as it was coming off the small ring at the front. It's ok now, but I think a bit of minimal fine tweaking to avoid the chain rub and keeping the chain on the ring at the front is required.Cheers.I'll slightly adjust the limiter screw again. Is getting the happy medium with these eh ?

 

[PpPete]

try turning the FD cable tension adjuster 1/2 turn clockwise, whilst watching the FD cage. If it moves left then its not up against the limit screw.
be prepared to turn it back the other way if it mucks up the shifting though.

 

[SimonJKH]

try turning the FD cable tension adjuster 1/2 turn clockwise, whilst watching the FD cage. If it moves left then its not up against the limit screw.
be prepared to turn it back the other way if it mucks up the shifting though.

Probably a silly question but - if you have this type of adjuster

Which way is clockwise?

 

[PpPete]

Probably a silly question but - if you have this type of adjuster


Which way is clockwise?

On a conventional adjuster "clockwise" shortens the outer, so the inner is correspondingly "slacker".
For an inline adjuster, you'll need to see which way makes it "longer" and which "shorter"

Be aware that it is very unusual to need to turn "clockwise" and thereby slacken the inner. I only suggested it in this case, as a means of verifying that it is indeed the L limit screw that needs adjusting.
99 times out of a 100 you need to go the other way, so "tightening" the inner (by making the outer longer), because the most common way these things go out of adjustment is by cable stretch.

 

[Fifelad]

Well wish I hadn't bothered tinkering, made things worse, knew that would happen ! Front derallier down change button has become incredibly stiff now and sloppy as hell change from big ring to small on the front after tinkering with cable tension ! And still have chain rub ! A trip to LBS again and denial that I have "fiddled" ;-)

 

[PpPete]

You did read the second line of post #4 didnt you?

 

[fossyant]

You did read the second line of post #4 didnt you?

Probably not !

 

[Fifelad]

Yes but then lost track of what adjustments I had made when nothing was working !

 

[Fifelad]

Right hate to tempt fate, fresh pair of eyes today and the problem seems to be cured ! A minuscule tweak of the lower adjustment screw to compromise not getting chain rub and not having the chain falling off the small ring! Wound back the cable tension so that the thumb shifter is changing fairly easily as before. Took for a ride up the street and went through the gears and no rub no chain coming off so fingers crossed ! Don't know how the trained eyes of bike mechanics know to give the cable tension a wee tweak what the general rule of thumb for tension ?

 

[gwhite]

I take it that you have a Double chainset. In this instance the drill would be to choose the large ring and the smallest rear sprocket and then viewing the FD from the rear, check that the chain clears the outer plate of the FD cage. If the chain is rubbing, then increase the cable tension by using the cable tensioner. Detailed instructions can be found here:
http://www.parktool.com/blog/repair-help/front-derailleur-adjustments

Of course the large/large combination should be avoided as some chain rub will be experienced.