Front changer issues

[bonker]

I recently adjusted my front changer. Although it works some of the times others it wont push the chain off the big ring at all or it pushes it right off the small ring and onto the bottom bracket.

Any ideas?

 

[Tim Hall]

If it's pushing it off the small ring, I'd suggest the adjuster screw needs a tweak to limit the travel.

Why did you adjust it in the first place?

Make sure it's parallel to the chain rings and at the right height. See here for a guide.

Could also be sticky cables - shifting from big to small relies on the spring doing the work. If the cable is gunked up, that's extra resistance the spring needs to overcome.