"metrompg" has made rolling resistance tests with various types of tires by rolling down a small hill and seeing how far the car would coast. he repeated this with 5-6 types of tires including a set of spare tire doughnuts.
the doughnuts tested the worst. even worse then old junk tires.
here's the link
http://ecomodder.com/forum/showthrea...eet-19126.html
HOWEVER here we have a young man who performed a mpg test on his metro, then replaced the rear wheels with spare tire doughnuts and repeated the test.
he gained 5 mpg with the doughnuts on his rear wheels. that would show that doughnuts are pretty good, way better than stock tires!
whats up with that?
thats a total conflict of results.
can anyone explain how this can be?