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I'm making a separate post to talk about why RR values aren't published by the tire manufacturers.
1) There are quite a few tests for RR and they give different results. In order to compare tires, the tests need to be the same.
2) The test facility needs to be the same - or at least correlated to some standard. There have been correlation studies for RR and indeed, each facility gives a slightly different result.
3) Then there is the problem of how to express RR. There is a major disagreement. The Feds want to use force (RRF) because those values emphasize smaller tires and therefore smaller vehicles.
But the tire manufacturers want to use the coefficient (RRC) because tire buyers already have their vehicles (and their tire size) and they need to know what the differences are for the particular size tire they would purchase.
This dispute was put in front of the GSA - and the GSA ruled that the Feds needed to go back and reconsider their position. That is what that Feb 2012 meeting was all about.
But even after that is resolved, there's the problem of tire size.
Both RRF and RRC vary by tire size. (That was the point of the CEC study that Smithers did). Unless a way is devised to resolve the tire size issue (like a formula or something), EVERY tire in EVERY size in EVERY tire line for EVERY tire manufacturer would need to be tested. It's been estimated that if EVERY testing facility in the world were to go 24/7/365, this would take 3 years - and in the meantime, no other testing could be done. No development of better tires or better rubber compounds. Not to mention testing of new products.
That, of course, is unacceptable.
So that's where it stands. There is a HUGE!!! obstacle.
I have my own opinions about how to overcome it, but having talked to the engineers at NHTSA, I don't think they will go there.
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