I am not very good at derailer adjustments to start off with. Anyway...I had my LBS put on new front and rear derailers, and now (about 2 weeks later) the chain rubs on the front derailer...ONLY when its on the biggest chainring...and the smallest gear in the rear. I was wondering how to get that to stop. I believe I would get into that gearing...then turn the H? screw on the front derailer...Till it doesn't make noise??? or does it need to go back to the shop for new adjustment (cable stretch?)