hi there all, thanks for the advice, problem now appears to be solved, works on the stand at least, not had chance to test ride yet!! it appears the problem was the xtr front mech, it seem that the outer plate was bent out over uniformally down the length of it and tha was enough to cause the rubbing on the new chainset, i checked it against another mech and found it was out by approx 2-3 mm . happy days and thanks for the advice. most post seemed to be pointing to a front mech problem which indeed it was !!!!