Age was the single largest difference in 2016. Even when looking at racial preferences (which on the surface perhaps seemed like the strongest divide), they more or less dissolve - at least in absolute terms - in the context of age.
I think it's reasonable to argue that age was the largest difference, but I don't think it completely overrode race. E.g. exit polls found that Sanders won about 50 percent of black voters under 30, which was a major underperformance compared to Sanders's overall share of the under-30 vote. Yougov also found that Clinton did better with non-whites over 45 than she did with whites over 45, and that she did better with non-whites under 45 than she did with whites under 45.
By "dissolving it (in absolute terms)", I meant that unlike with race alone, comparisons across age and race mostly show all racial groups of a particular age range supported the same candidate (by different margins obviously); young blacks, whites & others all voted for the same candidate, as did older blacks, whites and others. Among all race of a particular generation or age range, there was general agreement on who to back, even if the support levels did vary.
As far as the race gap goes, it looks relatively small by itself; it was basically 35-40 points between the two most contrasting groups (black and white). Along age lines, there was a nearly
80-point gap between the youngest and oldest voters (
70-
30 vs
70-
30). Said age gap more or less was the same for blacks (
50-
50 vs
85-
15) and whites (
75-
25 vs
65-
35) alike.