derailer or crank problems?

[1hill@aTime]

I'm having a bit of problems when i drop my chain i can't seem to pump it back up and have to get off my bike which is irritating, is it time for a new crank or derailer?

[Guest Big H]

You know what it may even be your STi. Shifting the front derraileur on our road tandem became worse and worse. I tried everything and spent hours to get it adjusted properly. I fitted a new front STi and it shifts crisp and easy. The old Tiagra's just worked enough.

 

Why did you mention chainwheel?????