How much do the stock 15" wheels weigh and are there lighter weight wheels available? How much benefit would there be to lighter weight wheels?
I think the stock 15" wheels are pretty light. They're utilitarian, covered. You could get lighter, but you're chasing crumbs.
weight comparison ce28 ecodrives (from Rays Wheels) 15 inch: 10.1 lbs 16 inch: 10.8 lbs Prius factory wheels - GII 15 inch 14.3 lbs 16 inch 15.2 lbs 5X100 mm holes 45 mm offset 6jj rim size 2004-2009 Prius 15X6JJ: 5X100mm PCD, 45mm offset 16X6JJ: 5X100mm PCD, 45mm offset 2010 Prius 15X6J: 5X100mm PCD, 45mm offset 17X7J: 5X100mm PCD, 50mm offset 17inch:11.0kg 24.3 lbs 15inch: 7.4kg The Rays cost close to $400 -each-. It would take at least 10 years of lots of driving to recover that cost with fuel saving. But they look really nice.
I presume you mean this wheel and yes, you are right, it is a really fine looking wheel. I was thinking of other advantages like unsprung weight, handling, etc. in addition to any fuel savings. There would also definitely be a good looking factor as well. RAYS - The concept is racing. [en]
That fuel saving is likely to be negative due to higher drag, if you do mostly high-speed cruising. In low-speed stop-&-go, or dealing with steep hills, the weight reduction would indeed save fuel, approximately in direct proportion to the reduction in weight of the car. For example, 17 pounds off 3400 pounds gross weight would knock 0.5% off the energy needed to climb a hill---but the energy recoverable by regenerative braking on the corresponding downhill would be reduced, too.
