Front derailleur: getting it right

[jefmcg]

I just replaced my front derailleur cable. The derailleur is tiagra, the shifter is 105 (I replaced the original shifters, which were tiagra). There doesn't seem to be a barrel adjuster or anything in the path. As far as I can tell, this means you have to undo bolt holding the cable, and readjust it then tighten it again to get it in the right position. Is this right, or am I missing something?

I had real trouble moving between the chainrings before I replaced the cable. Now it's moving fine, but when it's on the big chainring, it's over a bit too far, and rubs on the derailleur. I'm reluctant to undo the bolt and try again, as it's much better than it was - it's just not quite right. I'm I missing something that should allow me to tweak the "nearly right" cable, or do I have to start from scratch each time?

Already so used to the the noise of the chain rubbing, that when @vickster said "oh, it's your bike that's squeaking" it took me a few seconds of concentration to hear the noise.

 

[Brandane]

If it's shifting as intended and the only problem is that the derailleur is travelling too far outwards and therefore the chain guide inner plate is rubbing on the chain whilst chain is on the big ring (if I read your post correctly), then it sounds more like your limit screw needs adjusted rather than the cable tension. The high gear limit screw that is, and it needs screwed in a touch until the derailleur clears the chain.
Disclaimer: I might not have properly understood your problem!
P.S. Are you sure there isn't a small barrel adjuster where the cable goes through a lug at the top of the downtube? It's not always obvious as it looks like a plastic guide, but it is useful for fine tuning cable tension.

 

[Cyclist33]

I think it's the other way round in the OP. It says it is over a bit too far and rubbing on the derailleur when in the big ring, which would mean the derailleur is too far inward. So adjusting the upper limit screw in the way you're suggesting would push the derailleur cage even further in. Worsening the problem.

Possibly adjusting the lower limit screw clockwise will push the cage out a notch, also the upper limit screw anticlockwise to allow the cage to head out more.

My 105 shifters have barrel adjusters near where the cable exits the bar tape. They look like metal casings.

 

[Cyclist33]

In other words, the left hand diagram.

 

[Brandane]

I think it's the other way round in the OP. It says it is over a bit too far and rubbing on the derailleur when in the big ring, which would mean the derailleur is too far inward. So adjusting the upper limit screw in the way you're suggesting would push the derailleur cage even further in. Worsening the problem.

Possibly adjusting the lower limit screw clockwise will push the cage out a notch, also the upper limit screw anticlockwise to allow the cage to head out more.

My 105 shifters have barrel adjusters near where the cable exits the bar tape. They look like metal casings.

I see what you mean; but I was reading the situation as the derailleur was moving too far across, causing the inner plate to rub on the chain on the big ring. Easy fix either way, assuming that is the problem .

 

[jefmcg]

Thanks guys. I think the limit screws may do the trick. I'll let you know. Edit: or not ....

My 105 shifters have barrel adjusters near where the cable exits the bar tape. They look like metal casings.

Definitely not there. I guess it was a decision by Giant.

I replaced the shifters, cables and outers and tape. So I'd have noticed a barrel adjuster. It wasn't on the original tiagra fittings and wasn't part of the 105 kit I bought. The rear derailleur has the barrel adjuster built into it.

 

[shouldbeinbed]

Placeholder post so I can find it again when I go home and check my 105.

 

[howard2107]

You tube has plenty of videos covering this, watch a few, and you'll have it sorted in no time. I did, and believe me it is straightforward, but can take a bit of fiddling to get it spot on. There maybe a barrel adjuster on the gear trigger.

 

[Cyclist33]

Hmm, odd, I'd be surprised if there were no barrel adjuster... But it's your kit lol.

Photos of system from shifter through to mech, perhaps..?

My giant came with sora shifters which have the barrel adjusters on the shifter units. They look like little grey plastic vases.

 

[jefmcg]

OK, so I realised why it was missing. I replaced tiagra brifters, which have adjusters built in, with 105s that don't. So I just bought a pair of inline barrel adjusters from wiggle, but it turns out the downtube stop doesn't have have a thread.

I think I am back to square one

 

[slowmotion]

My Cinelli bike had no barrel adjusters at all anywhere for the front derailleur. I put in an inline barrel adjuster on the gear cable near the hoods. I still find adjusting the FD to be a right pain. The rear one is a doddle in comparison.
[media]
View: https://www.youtube.com/watch?v=2zUhwdXj7wc
[/media]

 

[Cyclist33]

OK, so I realised why it was missing. I replaced tiagra brifters, which have adjusters built in, with 105s that don't. So I just bought a pair of inline barrel adjusters from wiggle, but it turns out the downtube stop doesn't have have a thread.

I think I am back to square one

What is indicated by the term "down tube stop"? Sorry, it's not a term I've heard.

At any rate that barrel adjuster in your link is the same one my 105 cabling has and its sited about three inches from where the cable comes out from under the handlebar tape. So nowhere near the down tube.

 

[Andy_R]

I think it's the other way round in the OP. It says it is over a bit too far and rubbing on the derailleur when in the big ring, which would mean the derailleur is too far inward. So adjusting the upper limit screw in the way you're suggesting would push the derailleur cage even further in. Worsening the problem.

Possibly adjusting the lower limit screw clockwise will push the cage out a notch, also the upper limit screw anticlockwise to allow the cage to head out more.

My 105 shifters have barrel adjusters near where the cable exits the bar tape. They look like metal casings.

That will only have an effect on the FD when it's in the low range, no effect whatsoever on the FD in high range. Brandane has it right. Adjust the high limit screw - either in or out - just enough to get rid of the squeak. The gear change is working so the cable tension is sufficient.

 

[Cyclist33]

That will only have an effect on the FD when it's in the low range, no effect whatsoever on the FD in high range. Brandane has it right. Adjust the high limit screw - either in or out - just enough to get rid of the squeak. The gear change is working so the cable tension is sufficient.

Without sounding as if it's personal against brandane, no he didn't have it right. At least not completely. Mind you the op hasn't reported back on whether they tried the limiter screws or not, so...

 

[jefmcg]

What is indicated by the term "down tube stop"? Sorry, it's not a term I've heard.

At any rate that barrel adjuster in your link is the same one my 105 cabling has and its sited about three inches from where the cable comes out from under the handlebar tape. So nowhere near the down tube.

The picture from the packaging both illustrates what I meant by down tube stop and how these are meant to be fitted. Definitely designed to screw into the frame, rather be used inline.

(annoyingly I googled for inline, but ended up choosing something that wasn't right)