This chart puts it into perspective:
Bicycle and Motorcycle Chain Dimensions
Chain No. Pitch Roller Diameter Roller Width Sprocket thickness
Bicycle, with Derailleur 1/2" 5/16" 1/8" 0.110"
Bicycle, without Derailleur 1/2" 5/16" 3/32" 0.084"
420 1/2" 5/16" 1/4" 0.227"
425 1/2" 5/16" 5/16" 0.284"
428 1/2" 0.335" 5/16" 0.284"
520 5/8" 0.400" 1/4" 0.227"
525 5/8" 0.400" 5/16" 0.284"
530 5/8" 0.400" 3/8" 0.343"
630 3/4" 15/32" 3/8" 0.343"
( I spent many minutes spacing this table properly- only to have it reformat it on the post.- Look in the link for full explanation of all this and the charts, diagrams, etc.)
Thus, While the roller diameters of the 520, 525, and 530 are the same, the rollers width are a full 1/8" narrower on the 520 vs. the 530, and the sprockets too.
But most of you knew this already, and although that's what I had thought, this states it objectively.
Taken from here:
Notes on Sprockets and Chains