Lower pressures allow more sidewall flex, which in turn heats up the tire carcass (think of the Ford Explorer/Firestone debacle, where underinflation caused heat-related tread separation).

Unrelated question: The RS-4 is directional. Anyone have any issues running them on the wrong side? Our track is mostly right-hand turns, so my preferred rotation pattern is a diagonal swap (LF to RR, RF to LR). Obviously this would only be used on dry days, as it would affect water dispersion. Just wondering if there are any other considerations, like directional belts that might make for interesting handling if run the wrong way.

A friend of mine did it and said it was fine. Dunno in the rain but at least in dry conditions it's not an issue.

Just remember to put them back on the right way before the drove home :facepalm:
I was pleasantly surprised by these on autocross compared to the rivals. They didn't take as long to heat up as the rs3 and felt nearly there to the rivals.
I'll keep messing with the pressures for autox, over 32 psi an 8" rim was down on grip. I will try lower next time per all of the great feedback on this thread. My friend borrowed my car for a run and locked up the fronts, which sent the front pressures thru the roof. :vash:.

Just got my Hankook RS-4 245/40-15 and am like a kid at Christmas I'm so excited. 15x9 Konig Dekagram wheels arrived from Goodwin racing a couple days ago so will have them mounted tomorrow. The bad news is that the will go on a NB with no motor yet but it will give me the drive to push harder for the LFX conversion that is underway!

Be careful using chrome sockets on impact tools. I have seen a few that have shattered from that kind of use.

Had another track day today. Was supposed to be cool (6C) and overcast and ended up being cool and rainy. I completely concur that the RS4 is not a brilliant rain tire. Traction was severely limited and, worse yet, the feel is not at all confidence-inspiring. The window between some traction and none whatsoever is alarmingly small. Great for learning car control but certainly not great for keeping up with other cars on the track. I still have pretty much full tread depth, so it's not a water dispersion issue, just a compound that doesn't play nicely in cold temps. I may have to spring for some RA-1 tires for my 8" wheels next season, for when it rains here in the Spring and Fall.

I can partially confirm what DeerHunter said. I don't track mine but the RS4 don't like temp below 60 degrees. Above 60 they do great. Grip on the 245/40 is only slightly more than the BFG rivals 225/45. I would imagine that on engine swapped or turboed the RS4s would not make me a happy camper. But for now being all motor and only about 130 whp they are fine. I can still oversteer but very controllable. Once I up my power level I will be switching to Rivals at 245/40.

In an auto-x setting the 225 rival is quite a bit faster than the 245 rs4. Miata's train you to be heavy footed since there is no penalty for getting into it too much. With any tire and more power you're going to have to learn to roll into the throttle as grip allows rather than just slapping the pedal to the floor.

Yep. I nearly spun on rain-soaked out lap, behind the pace car, on RS4s in my friends WRL Miata.

Just drove to work on the RS4 in the wet (60F temps) today. I'm nearing the end of their usable life, but can easily still confirm that this tire has very very little window between traction and no traction. I can easily get the car to kick out sideways whenever I want with just a blip of the gas pedal on 1st or 2nd in the wet and I'm just a bone stock BP4W powertrain. At least on my setup, it is very easy to push too hard and have the front tires completely give up traction and the car pushes, or the back end completely gives up traction and you're are drifting. I haven't found a rhyme or reason to what dictates when the front or rear will give which makes it very unpredictable.

Typically for AutoX with my other Miata buddies on 205 RE71's I'm running 1.5-2 seconds faster than them in the dry, warm temperature days. On the wet event we did not long ago, I was running 5-6 seconds slower than them. Tires are the only reason I can figure for the huge time swing. We even switched drivers and the car was the difference as our times in the same car were not far off. I now refuse to even take my car to a wet event with these tires as it just isn't even fun. I'd rather co-drive on a better set of rubber. Moral of the story, RS4 in wet cold conditions are a bit scary.

Now that it's been a minute, does anyone have any life estimates for a street driven tire?

Either 225 or 245s on 9s. Might be an autocross or two thrown in here or there but nothing crazy.

I have 245's on 9's and this is the second season with them on - street driven in the spring/summer/fall, put away for the winter. Not a whole lot of miles on them total, probably less than 3K miles, but they've got plenty of tread left. Last year I did about 4-5 HPDE's and 1 or 2 AX's in addition to the street miles.

I could probably get away with a lot more street miles, but I think these have been cycled to death for the track miles - they're starting to feel a bit greasy under hard braking and I can break them away easily coming out of corners.

Life estimates; 10-15K street only, 2 HPDE seasons max depending on how aggressive you are.

Running 225's on 9's, we have close to 28hrs of track time on them, still >50% tread depth left. Coming from running nothing but Hoosiers the last three years its amazing how long these things are lasting. This is on a mostly stock powered NB2

That's pretty phenomenal. I would expect similar ish from a mildly driven turbo miata on the street. I'm not planning on doing burnouts every other light lol.
This is great info. These really seem to be delivering!

225 45 15's are on TireRack back order again. ETA 60-90 days if you are looking to order for next season. These RS4s are gonna be my track/daily tires, and switching to the Rival S for autocross once my RC1s are toasted.

I've been pleasantly surprised by how long they last on street and track driving. They get a little hot towards the end of an HPDE session, but they are otherwise very consistent. For autocross, they don't do well on the first run but keep enough heat in them for subsequent runs in ~70F ambient + cool breeze. Mine should otherwise lasted 2 years if my buddy could drive better. The RS4s (and well any tire) dont hold up when you spin and lockup repeatedly.

TR is out of the 245/40 RS4 until March-ish per TR rep FYI to anyone in the market. Ended up getting some RC-1s for this track season instead.

What is this Hankook "S2" compound? First I have heard of it.

Already available in any other model or size?
Softer/harder, longer/shorter wearing?
Source of info?

I dont know at all, it was something the rep mentioned. Not sure if accurate, hankook website doesnt mention it anywhere.

Update - these are listed again with an eta of 3/16. New price seems to be a bit lower at $136.35 a tire which is a huge bargain (imo).

The 225/45r15 RS4s are $116 at TireRack right now.