Front shifting issues

[thunderlips76]

Hi there,

So I’m having issues shifting front derailleur from small ring to big ring. Basically the shifting is fine but the trim position when shifting down means I have to basically wrench the left hand lever with massive force for the front derailleur to spring (rapidly) into position. When I say trim position I mean one click on the small left hand lever drops the the chain onto the small ring and a the big lever shifts back normally. If I press the small lever all the way there is a double click and the derailleur is impossible to shift back normally. I’ve replaced cables inner and outer and installed a new inline barrel adjuster. The shifters are 105 sti shifters. Another strange thing is if I manually move the front derailleur into the big ring position the left hand shifter moves smoothly. Not sure what’s going on.

 

[SpokeyDokey]

Model number may help for members to give the most relevant answers.

 

[C R]

Hi there,

So I’m having issues shifting front derailleur from small ring to big ring. Basically the shifting is fine but the trim position when shifting down means I have to basically wrench the left hand lever with massive force for the front derailleur to spring (rapidly) into position. When I say trim position I mean one click on the small left hand lever drops the the chain onto the small ring and a the big lever shifts back normally. If I press the small lever all the way there is a double click and the derailleur is impossible to shift back normally. I’ve replaced cables inner and outer and installed a new inline barrel adjuster. The shifters are 105 sti shifters. Another strange thing is if I manually move the front derailleur into the big ring position the left hand shifter moves smoothly. Not sure what’s going on.

It sounds like lack of cable tension to me.

 

[thunderlips76]

105 5800 on a Giant TCR Advanced 2018

 

[thunderlips76]

It sounds like lack of cable tension to me.

Yeah, so the tension is as high as I can get it on the barrel adjuster. And I basically can’t pull the cable tight onto the pinch bolt harder

 

[boydj]

I've found that a touch of slack in the cable, ie not quite as tight as possible, gives the best shifting on the front - particularly with a triple chainset, but also true of a double. This requires that the lower limit screw is just right and there is no problem getting onto the big ring.

 

[Deleted member 121159]

Are limit screws adjusted properly?

I'd just set up the front derailleur again from scratch following this video:

View: https://youtu.be/ZNG7g83lI-s?si=vNy2FhBAuorlJe2B

 

[C R]

Yeah, so the tension is as high as I can get it on the barrel adjuster. And I basically can’t pull the cable tight onto the pinch bolt harder

How do you set it up?

 

[Deleted member 121159]

I've found that a touch of slack in the cable, ie not quite as tight as possible, gives the best shifting on the front - particularly with a triple chainset, but also true of a double. This requires that the lower limit screw is just right and there is no problem getting onto the big ring.

Agree, sounds like a limit screw issue

 

[cyberknight]

c

I've found that a touch of slack in the cable, ie not quite as tight as possible, gives the best shifting on the front - particularly with a triple chainset, but also true of a double. This requires that the lower limit screw is just right and there is no problem getting onto the big ring.

i was going to say if you have the cable tension too tight its farks up the trim function

 

[thunderlips76]

Agree, sounds like a limit screw issue

Ah, ok this could be what I’m doing wrong

 

[SpokeyDokey]

As this is a 5800 with 4 position settings some answers already given may not be applicable.

The setup process of these is very different to previous iterations of 105 FD's.

These things need very high cable tension plus should come with a small device to help setup correct cable routing. Like this:

https://images.app.goo.gl/VYnztNRWiNeQaDQd7

Do you have one?

Google "Shimano FD5800 Dealer Manual" for the correct setup PDF.

This video may also be helpful

View: https://youtu.be/n8EyRpb1ibo?si=D0DR2P01YK7FUY5z

 

[thunderlips76]

Nope didn’t help. The limit screw moves the cage about but that’s not the issue. There’s a point where the FD “snaps” into position disconcertingly.

 

[SpokeyDokey]

Nope didn’t help. The limit screw moves the cage about but that’s not the issue. There’s a point where the FD “snaps” into position disconcertingly.

So, do you have the little cable routing device?

 

[thunderlips76]

No, but from the shimano FD fitting guide I have the cable in the right position.