[aerohead]

I located the materials I was thinking about,set them aside this morning,then left for town without them.Typical for Phil! I will bring them next time and post in sticky at top of page.

----------------------------------- Here's the crux of what they report: The "equivalent mass",do to the rotational inertia of the four wheel/tire combinations,constitutes an addition of 3% of the vehicle's weight.

----------------------------------- For the 15 vehicles included in the study,the average aggregate vehicle weight was 4,300-pounds,and each wheel/tire combo added the equivalent of 15kg (33-pounds),or, 60Kg ( 132-pounds) to the total vehicle weight.

---------------------------------- If one could buy a set of wheels manufactured from Unobtainium alloy,and tires constructed from Extraordinariumbutidine synthetic rubber,having no mass whatsoever,the savings to the motorist would be: 1.3 % mpg in urban driving,and 0.7 % savings at a constant 70-mph ( 111-km/h ).

---------------------------- Since we must settle for cast,billet,or forged Aluminum wheels,and conventional synthetic rubber tires,it looks as if weight savings in this arena will provide only dubious benefits.

------------------------------------ Lower rolling resistance is a worthy goal if it can be purchased,however mass doesn't appear to play any real significant role in potential for mpg improvement.