Front derailleur issue

[RussellZero]

Hoping someone just knows the answer for this before I take it down the LBS! shimano 105 front mech and shifters - shifts fine into the smaller ring, but pulling the lever to come back up to big ring doesn’t seem to pull the cable - but if I assist it by pushing the top of the derailleur with my foot while pressing the lever, it goes in fine and stays put. Just wondering if it’s new cable time, or something I’ve misadjusted - the cable is clamped tight in place I can’t see anything obviously wrong. Ended up this way after a visit to the LBS to get my headset bearings sorted. Tia!

 

[Mike_P]

Insufficient tension, the cable pulls the derailleur away from the bike frame to move it onto the big ring.

 

[Andy in Germany]

Hoping someone just knows the answer for this before I take it down the LBS! shimano 105 front mech and shifters - shifts fine into the smaller ring, but pulling the lever to come back up to big ring doesn’t seem to pull the cable - but if I assist it by pushing the top of the derailleur with my foot while pressing the lever, it goes in fine and stays put. Just wondering if it’s new cable time, or something I’ve misadjusted - the cable is clamped tight in place I can’t see anything obviously wrong. Ended up this way after a visit to the LBS to get my headset bearings sorted. Tia!

As @Mike_P says it's due to a lack of tension. It helps if you change the gears into the smallest ring, undo the pinch bolt so you can pull the cable through, pull the cable with your fingers until it's tight, and screw the cable down again.

 

[fossyant]

Could be tension, but most issues are old cables. Check the cable is taught in lowest chain ring. Also check it pulls through smoothly with cable disconnected from mech.

 

[SpokeyDokey]

Which model is it?

 

[Paulus]

Could be tension, but most issues are old cables. Check the cable is taught in lowest chain ring. Also check it pulls through smoothly with cable disconnected from mech.

That was my first thought, check cable is moving smoothly when disconnected.

 

[raleighnut]

Yep to all the above but also check the limit screws on the mech

 

[RussellZero]

Thanks all, makes sense given the handlebars would have been off and maybe the shifters moved around for the headset bearing. I’ll have a play today. Thanks!

 

[Mike_P]

At least it's only a double, triples are a real pain and I have posted before my crude but effective mention is sorting them out which is to hold the derailleur out so that the chain is happy on the largest ring using blocks of wood between the derailleur and seat tube. Set the gear lever to the largest ring, pull the cable tight and tighten the bolt