Front derailleur not reaching largest chainring

[Alison]

I have this problem where the front mech does not reach the largest chainring, the bottom bracket is 118mm wide and according to Sheldon Brown is the appropriate size BB for the chainset M560 but nothing I adjust allows the mech to reach the chainset, any help would be much appreciated

Alison

 

[longun]

Re:

Have you any pics? If the bb axle is slightly too long the crank will be too far away, even with the cable super tight. Have you tried taking the adjuster screws out completely? Sometime much gets stuck In the mechanism and it prevents it fro moving enough.

 

[longun]

Re:

The chainrings should be around the thickness of a pound coin away from the chain stays...ish

 

[Alison]

I cannot upload photos at the moment my phone is dead but the chain rigs are definitely much more than a pound coin away from the chain stays, so do you think I have too wide a bottom bracket?

Alison

 

[Alison]

Just checked and all our bikes are more than a pound coin from the chain stays as it happens and they are all fine

Alison

 

[ishaw]

Re:

Could be limit screws, could be cable tension I.e not enough pull due to slack in it, or the cable adjuster on the lever being at the limit not allowing adjustment. Could even be the bb of course. I bought what should have been the correct bb for some cranks, but turned out to be too long by quite a stretch. If memory serves it was an lx octalink bb and 118 long, needed much shorter in reality.

 

[Takingabreak]

think you need a 113mm bottom bracket for an M560 crank

 

[bowser]

Re:

I had a similar problem make sure the mech cage is aligned with the chain
When on outer chainring and not on an angle also make sure the mech is
Correct height above chain too high it won’t shift over.
If it’s a band on mech you can adjust it on the frame
Having said all this I rarely use the big ring especially off road !

 

[mk one]

Personally i would remove the cable and see where the mech rests then pull the mech out with hands to see if its tension or actually hitting the stop before the chainring. If the mech rests too far in board and it also hits the stop way before the ring then i would say it is the bb length. If it almost reaches then have a look at the stop screw, but that only really makes small adjustments so too far away and its not going to compensate.

 

[Alison]

Personally i would remove the cable and see where the mech rests then pull the mech out with hands to see if its tension or actually hitting the stop before the chainring. If the mech rests too far in board and it also hits the stop way before the ring then i would say it is the bb length. If it almost reaches then have a look at the stop screw, but that only really makes small adjustments so too far away and its not going to compensate.

I have not cabled it yet, just stretched it out, it starts so close that it comes off the smallest ring, I adjust the lower limit screw to get it on the granny ring and that prevents even further reaching the largest chain ring the best I've managed it the granny ring and the middle ring

Alison