Triple Front changer problem

[Crackle]

Front changer started getting difficult to get the big ring so I thought it just needed some adjustment of cable tension or limit screw. Anyway none of that really worked so I set it up from scratch again following Shimano's instructions to the letter and in order. Clearances, cable tension and limit adjustment. I had to let the top limit out beyond recommended to allow the cage to go far enough for the chain to catch as if I didn't it wouldn't. So if I'm not careful I can ship the chain off onto the crank but this is the only way it will change now.

It's improved but it's still hit and miss getting top and requires a bit of technique and care.

It never used to be like that, used to be quite smooth, so is there anything I can do to improve it, am I mising a trick or is it component wear making it a bit trickier?

It's Tiagra front mech and chainset but the middle ring is TA and big ring Stronglight, have been for a while and it was working with that combo.

 

[HLaB]

Did you check the condition of the cable inners/ outers and in the shifters?

 

[ColinJ]

I had exactly that problem on my Basso.

I put up with forcing the chain up and dropping it off the other side onto the cranks for ages until the strain finally snapped my front mech. I put a new one on - perfect changes again! The broken derailleur was nearly 10 years old and when I took a good look at it I could see that where a little ridge used to be had worn flat. It looks like that ridge is used to nudge the chain up onto the big ring.

How old is your front mech?

 

[Crackle]

Did you check the condition of the cable inners/ outers and in the shifters?

Condition is good, it's not a bike that gets used for commuting, however I was considering replacing the inner, I was thinking cable stretch and there's too much give in it now.

I had exactly that problem on my Basso.

I put up with forcing the chain up and dropping it off the other side onto the cranks for ages until the strain finally snapped my front mech. I put a new one on - perfect changes again! The broken derailleur was nearly 10 years old and when I took a good look at it I could see that where a little ridge used to be had worn flat. It looks like that ridge is used to nudge the chain up onto the big ring.

How old is your front mech?

It's about 4 years old and as it's a triple I mainly use the middle ring so I wouldn't expect that kind of wear but I shall have a look for any. It crossed my mind to up the spec of the changer anyway as the rear is 105.

 

[Crackle]

This one has been a 'mare. Finally I got this working properly again today. It's not the slickest of changes but it does now work when I want it to.

I think it stopped because I've got some derailleur wear, not much but enough to make a difference. I reset the front derailleur height as close to the teeth as possible and I moved it slightly out of parallel and trimmed the outer adjustment contrary to the instructions. This did the trick. Not before I'd been in the opposite direction and made it worse though.

My problem, which I think will require me to either go back to a 49 outer or buy a different derailleur is that I only run a 46 outer with a 38 middle. A gap of 8 is beneath the minimum spec of 10 for this derailleur.

Anyone got any good suggestions for a front derailleur which will cope with a wide or not so wide, range of front chainrings?

 

[yello]

Can't answer your latest question but this is a timely and interesting thread for me.

I have a similar problem and had guessed 2 possible causes;

1 - ergolever worn (I've posted on this)
2 - mech not set high enough

In my case, the change does happen eventually but I sometimes have to give the lever a couple of goes and even then I can feel the strain on the cable.

I was intending to re-cable anyway (outers too) as part of a 20k km service (hence me wanting to get both levers serviced) but am now going to look at mech wear too. Perhaps it could do with being replaced.

 

[MacB]

when I setup my Tiagra triple FD to the 24/36/46 I followed Shimano standard and it worked really well on the workstand but got the odd noise on the road, Stronglight chainset. I'm assuming things settled a bit due to the weight/force applied by actually riding. But when I put it back on the stand the derailleur cage was catching the middle ring when in the big ring. The tech specs for the FD state a min difference, big to middle, of 11t, raising the FD slightly higher on the ST sorted this out.

If you've only got an 8t difference can you not just mount the FD a bit higher to make it think the outer ring is bigger?

 

[Crackle]

Can't answer your latest question but this is a timely and interesting thread for me.

I have a similar problem and had guessed 2 possible causes;

1 - ergolever worn (I've posted on this)
2 - mech not set high enough

In my case, the change does happen eventually but I sometimes have to give the lever a couple of goes and even then I can feel the strain on the cable.

I was intending to re-cable anyway (outers too) as part of a 20k km service (hence me wanting to get both levers serviced) but am now going to look at mech wear too. Perhaps it could do with being replaced.

That sounds prety much like mine, eventually the shift happened but then it came to a point when it didn't. I replaced my cable and lubed my shifter too but it made no difference. It wasn't until I sat with my nose against the deraileur and watched it all happen did I notice the pivot flex which seemed to be stopping the shift. Manually twisting the mech improved things. So I moved it all closer, swivelling off parallel to compensate for the flex i.e. nose out, which eventually sorted it out. I'm now back to a shift with an extra heave at the same as slowing the cadence and listening to the catch before I put the power back on.

when I setup my Tiagra triple FD to the 24/36/46 I followed Shimano standard and it worked really well on the workstand but got the odd noise on the road, Stronglight chainset. I'm assuming things settled a bit due to the weight/force applied by actually riding. But when I put it back on the stand the derailleur cage was catching the middle ring when in the big ring. The tech specs for the FD state a min difference, big to middle, of 11t, raising the FD slightly higher on the ST sorted this out.

If you've only got an 8t difference can you not just mount the FD a bit higher to make it think the outer ring is bigger?

I remembered your thread mentioning exactly that. Initially that was the direction I went in but that made things worse. As per my reply to Yello, I think this is just a wear problem and I'm so near the mech tolerances that it didn't take much to stop it working all together.