Ah, now I get it. I use TireRack a whole bunch too, way too much time on there. But I have found they are only useful for current models of tire. The 315 on the Duster above is a Rival, not a Rival S 1.5. No idea how much difference that makes.
I wish they would expose the old catalogs so we could get back to some info on the older models. I understand why, I am sure they feel they wouldn't be safe to use even if someone found a set in a basement. But it sure is needed for research purposes.
Speaking of TireRack, I hate how they changed the spec catalog. Scrolling to the right sucks, I sure miss the vertical catalog arrangement they used to have. Much easy to compare specs.
Maybe it is time to start self capturing the specs of the current tires so later on I can review them.