I'm going to change my Sora shifters to a used pair of Ultegra shifters. I've read the Park Tool explanation and I'm all go with that. My question is, do I need to change the wires or can I just reuse the cables (brake and derailleur) that I'm running now? Thanks.
Edit: Just wanted to clarify, I don't have any new wires, so if I did need to change them, I'd have to go fetch new ones.