Chain Rubbing on front derailleur

[Truth]

Not sure whats happened Bazzer , yesterday evening the chain was rubbing and then last night , when I tweaked it a quarter , it stopped .........
Anyway the journey in was great and no problem , lets hope it stays like that
Have a good weekend everyone !

 

[Truth]

damn , damn , damn ! Its started rubbing slightly again. Adjusted the "barrel" on the handlebar trigger gears and its made no difference and the little dérailleur screws made no difference either , I just can't understand it really???
May have another look in the morning but only really affects one gear now really

 

[Truth]

Large front and small rear cogs are fine. It's small front/small rear or large front/large rear combinations that you want to avoid.
Sounds like a little more tension on the cable is needed to move the front mech out wards. If this doesn't work then it's the limit screw that needs a tweak.

Next question , as I can't see a barrel adjuster (other than the one right on the trigger lever which is doing nothing) on the cable , how do I increase the tension to move the derailleur out ?
Sorry. Again if this is all very basic stuff to most !

 

[Bazzer]

Assuming the rubbing has come back on the middle ring of the chainset, if you are sure the adjuster near the trigger isn't doing anything, have a look along the cable all the way to the front mech. If there is no other adjustment capability, I think you have two choices. Firstly buy a barrel adjuster and fit it to the outer cable. See @derrick post earlier. Or loosen the cable near the front mech and using all three hands move the mech sufficiently across to stop it rubbing, hold the cable tightly with pliers to stop it slipping and then tighten the locknut with an Allen key/spanner.

 

[Nigelnaturist]

To adjust an FD from scratch,

1 ensure your left lever is in the low postion,
2 disconnect the cable at the pinch bolt on the FD,
3 make sure the FD cage is parallel with the rings,
4 adjust the low stop screw so the cage is about a 0.5-1mm from the inner ring/chain,
5 reattach the cable pulling taught with pliers try not to damage the cable, this should take up the slack you would normally take up with the barrel adjuster,
6 once done shift up through the big rings, if its doesn't move onto the outer front ring the high stop needs to be undone slightly.

Tip if when the cable is detached hold the cage with one hand and the adjust with the other the movement will be felt easier than looking for it visually, once you know which screw is the low stop you will know the other is the high stop, also if nothing happens chances are its the high stop you are adjusting, so adjust the other, then reattach ect..

 

[Nigelnaturist]

Images of barrel adjuster postions

 

[Truth]

Thanks Bazzer and Nigel! The rubbing is worst when in the middle front (2) ring and the largest (7) back cog. Also rubs a tiny bit in the largest front and largest back.
I will have a look later, just worried about buggaring it up and not being able to use it!

 

[Nigelnaturist]

@Truth need to clarify, middle front (2), largest rear cog, is usually 1 which is the low gear, biggest gear smallest rear cog is usually the higher number 6,7,8,ect.

You shouldn't really use the the large front chain ring and largest rear cog (1) this is known as cross chaining, and will lead to unnecessary chain/cog wear due the more extreme angle of the chain, and because of the more extreme angle chain rub on the FD cage is more than likely, however if it is the large front and large gear i.e. small cog, than the FD is not moving far enough and the Hi-stop screw needs slacken off a touch or a little bit more tension on the cable, which from what you describe is likely,
if its rubbing on you middle front chain ring and your rear smallest cog (biggest gear, 7) your FD cage needs to move slightly towards the large chain ring, adjusting your hi low stop screws will have no effect, all these do is stop the cage from moving to far so that the chain doesn't come off, so you need to adjust the cable tension, as I described. If you follow what I wrote before, you can't go wrong.

 

[Truth]

What I meant to say was middle and big front and smallest back was when there was rub, I am bloody hopeless, feel like I am wasting peoples time sometimes! SORRY
Anyway its sorted!
Did some fiddling about.
Loosened off the barrel adjuster by the trigger first
I actually adjusted the back gears then by loosening the screw and then (i know you said not to Nigel BUT it seemed to help) adjusted the front derailleur screws. I saw for the first time that there is very slight movement there.
Can I add at this point that a bike frame would have been priceless while doing this, luckily my neighbour helped me as he saw me riding up and down the road aimlessly and asked what was wrong!
He knows a thing or two about bikes and gave me a few pointers as well as you guys . He also held the bike with me while I went up and down the gears making adjustments.
Anyway , I now have a clean bike, clean chain, clean cogs, clean everything in fact BUT best of all a rub free ride!
Thanks again all and I will leave you in peace now until my next daft question arises at some point in the future .
Have a good weekend.

 

[Bazzer]

Glad it's sorted.
(Until the next time )

 

[Nigelnaturist]

@Truth anytime, glad its working right.

 

[mrbikerboy73]

@Truth those guys beat me too it and gave far more complex and informative instructions than I could have done!
Glad you've got to sorted out

 

[Truth]

Cheers, genuinely really appreciate all the help with this and other previous daft questions
Sometimes I don't think you lot know how useful and helpful you are

 

[Nigelnaturist]

Cheers, genuinely really appreciate all the help with this and other previous daft questions
Sometimes I don't think you lot know how useful and helpful you are

One day you will be doing the same.

 

[Truth]

I VERY much doubt that mate !