NASA announced tonight at the National Championships that 944 Spec, along with Spec Miata and Spec E30, will be moving to a new Spec tire for 2013, the Toyo RR. Being painfully aware of the last attempt at a tire change, I have gathered as much information as I can tonight (I did not have advance knowledge of this). I talked personally with Jeremy Croiset and Ryan Flaherty from NASA, the Toyo engineers, and Tyler Palmer, who was involved in some of the testing for this tire (and was under a non-disclosure agreement until today).

Here's what I know so far.

1. The tire is a 2 line near-slick DOT tire - looks much like a Hoosier R6, or BFG R1. No shaving.
2. The rain tire will remain the RA-1, which will remain legal in the class.
3. Price is reported to be "the same" as a shaved RA-1. I take this to be about $15-$20 more per tire than a full tread RA-1, but was not given specific pricing info for our size. I was told the SM tire will retail for about $168 (per the Toyo Engineer), which is $16 more than the Tire Rack lists for a full tread RA-1. Extrapolating that to our size would be $188 (Tire Rack RA-1 price of $172 + $16). Don't quote me on this, I'm just trying to get a ballpark figure on this with the information I can gather.
4. The tire was built by Toyo specifically for to NASA's requirement as a Spec tire, based on what we know and love from the RA-1, and what what learned from the R-888 debacle. Primary goals were consistency over its life cycle, and longevity, and replicating the forgiving nature of the RA-1 at a higher performance point. Making the new tire work, as a bolt on upgrade was also important - i.e not requiring a substantially different setup as the R-888 did.
5. Using the same suspension settings, and starting tire pressures, Tyler Palmer was substantially faster at Buttonwillow in his first session, and felt that the transition was an easy one. I'll let him fill in the details, and asked him to chime in when he can.
6. The tire has been tested throuh 18+ heat cycles, and reported to be consistant through that, as well as two consecutive 3 hour enduros. I can't yet verify this on our cars.
6. Toyo Bucks from this date forward will remain valid for a "longer time" so as to not require you to buy more RA-1's before they expire. I don't have details on what that means, yet.

I hear the collective "not again" already, and I certainly understand it. I lived through the R-888 era, and was quite happy to have the RA-1 back, as I'm sure most of you were. After expressing my concerns, I will say that both NASA and Toyo are very aware of the stakes involved in getting this right this time. The Toyo engineer used the phrase "after the R-888 debacle", which was good to hear him own up to. While I am encouraged that the process of this change have been carefully thought out, and more thoroughly tested (on our platform specifically), change is painful, and our class wasn't asking for it. I have asked as many questions as I can think of tonight, and will have access to the major players involved in the for a few days still, so post up your questions here, and I'll work to get them answered.

A week from Friday, I will run the RR in a 3 hour enduro, and will be able to give you more personal feedback on them.

I am very excited about this! Can't wait to get my hands on a set.

I must say I'm NOT excited about this. I previously ran Hoosiers in Cup. Yes they are definitely faster. They are also much less fun and put a lot more stress on suspension components. I find it very hard to believe that a tire with more stick is going to last as long as the RA1 also.

I love being able to slide the car and the way that everything is so progressive with the RA1. With "better" tires, the penalties for errors are higher at higher speeds and I've found that they usually aren't as progressive into a slide - they are more apt to let go suddenly.

I also have two brand new sets of shaved RA1s

Interesting. As I only have experience with 1 new set of RA1s on my spec car and Hoosier R6s on my vette, I cant really give good feedback on this like some of the experienced guys in the class can. I don't know if it would do any good anyways since these deals are made by those who know best up high.

Found out they are already listed on their website: toyotires.com/node/265154

Just based on their website also, they rate the dry handling higher and tread life lower on the RR as compared to the RA1 indicating that they are trying to make a slightly faster tire at the expense of slightly reduced life cycle. Makes sense I guess.

Compare the specs.

Its a lighter tire by 1 lb 10oz
Max load has increased by 33 lbs (stiffer sidewalls?)
UTQG rating is down to 40 from 100 (stickier compound)
Load radius is increased too. (stiffer sidewall or thicker rubber in the tread area)
They say in the specs that they are the same overall diameter but revs per mile is down on the RR which means its smaller in diameter.

Of coarse it's gonna be faster, it's wider, lighter, smaller diameter and stickier compound.

I'm glad I didn't buy more RA1's this year.

Will we be able to use up our remaining RA1's next year????

The RA-1 was rated at a treadwear of 40 until 3-4 years ago. The change to 100 was made to keep it from competing with Hoosiers etc., I would guess. Purely marketing.
Keep in mind the comparison tables are based on tires as delivered - unshaved. I would expect an 8/32nds tire to have more treadwear than a 4/32nds tire. What we really need is a comparison to a 4/32nd's RA-1, though that brings the variables of shaving (rounded shoulders, or square, what exactly 4/32nds is, etc.). The weight is also likely due to the extra tread depth.

Ken, the RA-1 remains legal, as a rain tire, and it would seem impractical to limit to wet races on a rule basis.