Originally Posted by
Slaninar
I don't think small tooth difference will create problems. Not by itself. Larger tooth difference is worse What could cause problems is FD cage shape. If it is appropriate for a 48 T chainring, it will not match the curve of a smaller, 42 T chainring. But that doesn't have to be a problem - for me it works (42-32-22
It's not the tooth difference per se and it's not the curvature of the cage. Again, it's the depth of the inner cage plate that will cause the problem if the two chainrings are too close in tooth count. Either the inner plate will hit the inner chainring or you will have to set the fd so high that shifting to the large chainring is compromised.
Of course it works for you, your two outer chainrings differ by 10 teeth. Substitute a 38T middle ring on your crank and see how well that works.