On my Flex... My total weight for my 255-45-20 Goodyear GS-A's & 20 x 8" stock wheels is 63 lbs.
I believe the tires were 31 lbs(TireRack specs) so wheels were 32 lbs. This was weighed on my home scale which is quite accurate.
Going to lighter combos... one can save many lbs.
I am currently running 235-50-18" Michelin Pilot Super Sports (25 lbs) + my 18" x 9" TSW Interlagos (18 lbs...) so I am saving 20 lbs a wheel in rotating mass... Even though my tire diameter is 7% smaller than stock... My mileage is as good or better than stock... and my stopping distances are much shorter... AND... the handling with these tires is UN-BELIEVEABLE!!! My EB Flex actually handles better than my G8's, because they tend to over steer with extra power... where the Flex can go thru the same low speed turns with neutral handling, powering out with the Front wheels pulling.
We love our Flex... Always overachieving!!! And this after 50+ new vehicles over 50 years.