I've been picking everyone's brain about a shifting issue. One time my new bike RD won't upshift. The next time, it won't downshift. Someone mentioned to check for anything causing friction. I disassembled the shifter cable from front to back, and all looks well, but could it be that the cable housing going to the derailleur itself is too short, with the result being that the final bend is too sharp? Take a look and tell me what you guys think?