I'm going to have to replace my cassette, chain and at least big chainring SOON. I'm probably going to LBS for cassette and chain. I'm going to drop from Dura Ace to Ultegra because the Dura Ace didn't really last do to my neglecting to change that $50 chain. Probably use cheap chain and remember to change it every 2000 miles. My question is I see Dura ace (it's a 9 speed) chainrings on ebay. There are an "A" and a "B" they both have 130mm spacing. Either should work on my bike shouldn't it? $145 for both chain rings new. Bike shop is double that.