Take much out of context?
Some light reading on rolling resistance, to which the rubber compound can be a contributor (that's what I actually said).
http://www.tirerack.com/tires/tiretech/techpage.jsp?techid=29
The point I'm trying to make is that things out of our control like being stuck in bumper to bumper traffic or hitting red lights all the way to work probably do more to effect the average persons MPG than a little extra weight.
Just trying to put it into perspective instead of having a chicken little reaction to more weight.
Well, you said this:
It's not weight that kills mileage, it's increased rolling resistance along with improper gearing for the tire diameter.
My point was and is that weight IS a factor. Whereas you stated it was not.
Weight is a factor, as is rubber compound, casing construction, tread pattern, tread depth, tire diameter and section width, inflation pressure, etc., etc.
Driving conditions are definitely a factor too. As is how someone drives.
I don't need to read Tire Rack's explanation concerning rolling resistance. There is no new info there for me.
I've spent most of my life involved in cars and bikes and learning what works for them.
By far the most influential aspect in learning about tires, have been the years of involvement in Land Speed Racing, and Professional Dragracing, where tire construction and the understanding of it is absolutely critical.