Front derailleur problem

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Just changed my road bike to an APex rear derailleur, mavic chain with a wipperman link, SRAM 11-32 casette. My front derailleur now overshifts and dumps the chain off the big ring. Tried the high limit, if I tighten it too much then the gears wont change, if Im pedal very lightly on the change then it will stay on, but any kind of pressure and it jumps off.
Before I swapped everything the front derailleur was fine, never threw the chain.
Where do I go from here, do you think the chain has anything to do with it, its this one from CR, HERE
 

gbb

Legendary Member
Location
Peterborough
I suppose it's worth checking the chainrings are'nt worn. Possibly performed fine with the old chain that had worn with the chainrings, now there's maybe a problem meshing with the new chain.
 

PpPete

Legendary Member
Location
Chandler's Ford
Did you change the shifters too?
Isn't the cable pull on SRAM different? (even though the cassette mounting and spacing is the same)?
Could be wrong about that though.
 

bad boy

Über Member
Location
London
This is interesting - I would check your chain rings at the front for wear make sure they are not 'shark fined'.

Partools website gives a good pic of what they may look like worn.

Presumably if all is ok chainring wise the H limit screw would stop the chain throwing off - its odd that you cant find any middle ground in that with adjustment it either throws or doesn't shift up !?.

Check the chainrings before you mess around further with it, how many miles did your old cassette/chain do ?
 

Mad at urage

New Member
Is the chain slightly slimmer? Inside 'arm' of the F Derailleur pushes it up onto the ring, outside 'arm' stops it going too far and falling off. I have noticed that some FDs have a wider gap between the arms than others (helps to stop chain rub if the ring is slightly out of true :whistle: ), but this could (?) mean that a narrower chain slips over the ring when the inner arm pushes it up?
 
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tincaman

tincaman

Guru
From new the bike has done 1500 miles, the chain shows no wear on a chain wear guage.
Today I had another play with the adjusment, rode out and took a screwdiver, tweaked it until it would just change reluctantly to the large ring, still came off one out of three changes




IMAG0214.jpg

IMAG0218.jpg


IMAG0219.jpg
 
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tincaman

tincaman

Guru
I am starting to think it may be a bit worn, can you get these chainrings OK?
 

MartinC

Über Member
Location
Cheltenham
Those teeth look worn. You should be able to get Rival chainrings, if not Stronglight or TA are available. By the way the front mech looks a bit too high - the outer plate need to be just 1-2mm above the big chainring.
 
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tincaman

tincaman

Guru
Adjusted the FD to move it closer to the chainring, and seems much improved, changed ok over a few hundred yards down the road. Out over Dartmoor tomorrow to give a good test.
I have the new Sram Apex 11-32 cassette and long rear derailluer, with a 50-34 compact on the front. Should be able to get up anything now
 
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