Let's see. I see 6 clamping bolts, as opposed to the original 10. A very nice Hex shaft, which eliminates the custom hub and it's associated hardware. Maybe a thinner web? While this all creates a bit of weight savings, I'm sure it was done to simplify the assembly.
As always, these wheels look fantastic! How often were they taken off for retreads, repairs, etc...? They look just about bomb-proof to me. Now, where's the rest of the robot.
BEN