Originally Posted by
chewa
As above, though to preserve chain life I tend to try to avoid cross chaining too much. On a 10 sprocket cassette I would only use the smallest 7 or 8 sprockets with the outer ring and the larger 7 or 8 with the inner.
I know modern chains are pretty flexible, but I have had a couple snap on 9 and 10 speed rears.
I agree and avoid the big-big or small-small combos. This bike seems to have no issue with small-small, and all the problem is with big - big, plus a few more on the low end of the cassette. studying it, it would appear the chain rings are too far outboard of the cassette (or vice-versa) with no way to adjust this.
I could/should have added this to my OP: off the bike, in a quite environment, the noise is directly attributable (by sight/sound/feel) to the chain on the large ring. In other words, it's not DR adjustment or improper use - the chain just rubs horribly on the ring when on the lower 1/2 of the cassette.
All comments and suggestions welcome.