How do I set up a band-on front derailleur?

[Jonny69]

I was wondering if anyone could walk me through how to set up my front derailleur because I'm really struggling getting it to shift correctly. It's a Shimano SIS band-on with indexing. Used to work fine before I took it off. The mistake I made was I didn't mark or measure the position on the seat tube.

So through trial and error I found that the height had to be low enough that it didn't clip the chain on the smaller ring at the front and back. I've got it in a position which seems to be the best compromise for shifting which is where the bottom rearmost edge of the derailleur chain guide only just doesn't hit the big ring, but it still isn't right. In that position the chain rubs the derailleur when cross-chaining on the big ring and it struggles to get the chain onto the big ring. If I have the derailleur so that it will shift it into the big ring, most of the time it flings the chain off. Instead of shifting, it seems to look like it pulls the chain onto the tops of the teeth if this makes sense? But these Shimano rings have index markers so you put them in the right place on the crank spider.

For the rubbing, I was hoping I could set the stop slightly over so it pulls the chain on but then the guide would drop back slightly so it doesn't rub. But this doesn't seem to be the case.

It's annoying me now. Why are front derailleurs such a crap design compared to the rear ones? And there's no cable adjustment on it. Grrr.

 

[47p2]

For the height you need to line the outer edge of the cage with the teeth on the big ring and the cage should be between 1mm & 3mm above the ring teeth, the cage needs to run parallel to the ring

 

[Jonny69]

Brilliant! That's a good start.

Good point on the parallelism - I'll check that from above since I didn't do it before.