Front derailleur alignment

helston90

Eat, sleep, ride, repeat.
Location
Cornwall
Pre winter my front derailleur worked fine- perfect in fact, but in the last few rides it has been playing up with chain rub without my having done anything to it to cause it to happen.

It has now got to the point where in the middle (triple) ring the derailleur is catching on the teeth of the large ring, does the derailleur have an 'up' movement or is it just side to side? Have I used the inline adjusters to pull the cable making the mech too far over? or is the whole thing just a bit seized and should be attached with some WD40 and some repeated shifting to loosen it all.

I'm thinking the latter as if I shift up from the granny ring or down from the big ring the mech will sit in a different position- surely it should be central no matter which way I've come from?
 

Turbo Rider

Just can't reMember
Cable tension most likely. If you cant cure it with that, try the screws, but not too much or you'll suffer a high degree of chain dropping off...if it's neither then it could be chain and cassette wear or a problem with springs in the derailleur itself...or maybe just a frayed cable...start with tensioning though...
 

migrantwing

Veteran
The mech can be moved up and down. The dérailleur cage needs to be about 1-2mm above the largest teeth on the largest chainring. I'm guessing while your bike has been stored over the Winter, it's been knocked or the derailleur wasn't tightened up enough and it's slipped. There's a knack to setting up a triple front derailleur as opposed to a double. Someone on here with more experience of triples will surely be along to help you soon.

My OH has a triple where as I have a double (compact) set up. Her gears need looking at, so I'm in the same boat as you. It sounds like I'm more mechanically minded regards bike maintenance than you are (no offence) but a triple is still new ground for me :smile:
 
OP
helston90

helston90

Eat, sleep, ride, repeat.
Location
Cornwall
Stop everything.....
I have fixed it. After more tweaking and adjusting and cups of tea and swearing I finally decided to adjust the vertical position of the derailleur- at which point I noticed both of the of the bolts holding the front derailleur plate in place had worked loose (I don't know how, I've never touched them- maybe that's how?) so I simply did those back up- this pulled the derailleur up, held it in place and I simply adjusted the tension as normal. This is why no amount of on road adjusting was helping as the whole mech was flapping around like a whales tale.

Thanks for your thoughts on the cause- the bike has been used all winter rather than stored all winter so I was proposing salt damage/ corrosion but hopefully it's all good. I will go out for a ride now just to make sure. :sun:
 
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