I have a shifting problem on a bike that has a crank with a triple set of chainrings. The bike is a tandem. I have to put a great deal of effort to get it to shift into the big ring. Where should I start? Is there a simple adjustment I should look at first or should just jump right to replacing cables and housing?
* STI shifters
* 2004 Shimano Tiagra
* probably same cables/housing from 2004.
* bike has 4000 miles on it, maybe more