RT615K PSI and Temp

I posted this on miata.net but got no answers. This seems like a better place for this.

I've been a couple track days with Hooked on Driving and the Big-O tire people are always there to help out for free. They start you with a nitrogen purge and fill to a baseline cold setting, and after you come in they take the temperature hot. And then they'll readjust the PSI based on the readings.

The Big-O guys like to set the pressure at around 26 PSI cold, which totally conflicts with what most of the Miata guys run, which is 30 PSI or more (35-38 hot?). On the one hand, I've got the Big-O guy saying he's got 20 years of experience doing this, and if you fill the tires that high, then you'll skate off the track. And then right next to me is Larry Oka saying if you fill the tires to 26, then the tire will pull off the rim. They were both exaggerating for effect, but they couldn't have more opposite opinions.

I went with the Big-O settings simply because they were doing the air fills and weren't going to do something they thought was dangerous. I have since replaced the steel rims with 15x7s and got brand new Falken Azenis 615Ks in 205. So I went again went with the Big-O settings, since they were at the track. The hot temps I got back were like this (outer, middle, inner)

LF 103, 109, 115 (26.6 PSI) LR 107, 109, 112 (26.6 PSI) RF 120, 108, 108 (26.3 PSI) RR 124, 113, 107 (27.6 PSI)

So you can see these hot temps (just off the track) are rather cold. Bear in mind these are brand new tires, the temperature was about 50 degrees out. The Big-O guy says I need a good hot day to cycle the tires and get the polymers working, and that they might still have release agent on them (I doubt this, this was after my 3rd session of the day).

And you're probably thinking I didn't push the car hard enough, but my CMS lap timer app says I average 1.1g at mid-corner, and I can tell you I have a bit of slip through every corner. I'm definitely pushing the tires. The car does feel balanced, the tires just aren't getting any heat in them.

People that know Falken Azenis 615Ks, what are you running for tire pressure and what temps are you seeing across the tire?

I got in a Miata with one of the coaches and he ran NT01s in 225, and man did those stick. Considering that route when these tires wear out.

i am watching this thread intently, having driven my '94 miata to work this morning on those exact same 615k's. they are my car's street shoes, however.

i bought NT01's when they first came out for my autocross SM-class E30. They stick like crazy, but needed heat in them or they didn't work at all.

answering even though I don't have an answer for you

the a-x folk that drive Miata's tend ( with the Toyo's ) to run much MUCH lower pressures than that ( in the upper teens )

different tires and different type of event ... but ....

I can't speak to tire temps but the sweet spot for me seems to be around 30 front 28 back PSI hot on my older RT615's and they sure don't "pull off the rim".

geez fellas. i run way too much. like upper 30's.