Over the weekend, I was told something that was contrary to my understanding about tire pressures. Keep in mind I would not even have listened had it not been a very reputable source. I was told that radial tires make more heat with a higher pressure. My understanding has always been that a lower tire pressure produces more heat and grip. I.E. Add tire pressure(or do nothing) when hot outside, subtract pressure when cold outside. Needless to say the conversation left me confused; As I said the info came from a trusted source in the community. Anyone who can shed some light on what I thought was a simple subject, would be appreciated.
The Pirelli vendor has told me that they look for 35 psi hot pressure. If it is cold out they recommend starting at a higher pressure cold to arrive at the recommended hot pressure easier. That's pretty much opposite of what I had been doing for years with bias and other brand tires. Sounds kind of like what you were told?
You need to think about it though. If it is cold out you will not build as much heat.....which in turn means that you will not build the PSI up. The reason you set the PSI low is so that when you get the tire hot it reaches the proper operating PSI.
The contact patch is smaller with more air in the tire. Smaller contact patch means less tire touching the ground but still doing the same work. More heat. Get it?
Yeah, Moose told me the same thing when we talked. I was under the impression all these years that the carcass of the tire would flex more with less pressure and build more heat.
? I have been told by 2 different people (on the same weekend) a difference of 5psi to run in my pirellis. There seams to be a big difference in opinions when the weather is not perfect (70-80 and sunny). Who do you listen too?? Or who do you kick in the balls if you go down because you dont have any heat in your tires. I went down 1 time last year and it was MY fault . I had put extra air in the tire (40 some psi). Forget to check it before I went out on a wet track . 6 laps into the session I was starting to push it and BAMMM. The tire was still COLD. I know I didnt help you out Doug but Im also a Dummy when it comes to psi and I always ask someone a TRUST with my safty.
That’s what I read in a book about tires. It is the flex in the carcass that builds the heat into the tire so on cold days you lower the pressure a small amount to cause it to flex more and get to the optimum pressure.
I dont know that anything was decided here except the following: It does appear that too much pressure will not build heat. I dont think anyone will argue that 40PSI is too much and will result in a cold tire. On the lower side, I am not certain. The reason I ask is really due to what looked like cold tearing I was getting at VIR in the morning. I was using warmers and still having a problem. I was told to up the pressure 1 psi and see what that did. Not so much luck. I guess I start working on the rebound again.
As told to me by those at trackside supply, and 1 pirelli engineer I ran into at Barber's last year. The "Perfect" temp for SuperCorsa's is 36 psi when checked IMMEDIETLY after coming off track hot. When it's 70-80 degrees out, that means 30/29 cold. When it's 50-70, 31/30 etc. again, check right after coming off track hot for 36 psi. Seems to work for me. and before anyone sez it.....I crash because of my own mistakes, no blame placed elsewhere.
hmmm. i'm confused too (no surprise). i have understood that: - there is no target hot pressure for the front. just run it where tire wear and feel under braking is right, and - the target hot rear tire pressure (on pirelli supercorsas) was 35psi. so do whatever gets you to that point. i always thought the way to do that was: - if your hot pressure was too low - to let out some air. it will flex more and build a higher hot temp - if your hot pressure was too high - add some air. it will flex less and not get as hot. BUT. i have not proven these out myself, and don't know them to be true. i pretty much have just set cold pressures at 30/30 and my rear pressure is almost always within 1 pound of 35...so i have always just left it alone.
any of the tire guys on the board?? i'd really like some answers as well. I'm a Florida guy so when i travel up North and race in cooler weather I'm totaly lost
The best thing to do is when you get to the track.....go ask your tire guy. He is there to help with stuff like this and will give you the info you need for that weekend.
tire guy advice is sadly like assholes.. every one has one , they are all different, and most of em stink. maybe if every Pirelli guy gave the same info i'd believe it. that and if they stopped screwing me outta my certs LOL
no. compression. take some out. _______________________ the rest of ya got me all confused. i used to set my michelins with a 6-7lb difference between hot and cold. seemed to work. my usual starting pressures were 30/28.5. didn't have to mess with it much. 1/2-1lb adjustments, if i did.
I am not too sure what you mean by cold tearing but I have noticed on Michelin dot's that, towards the edge, straight grooves about 1mm deep and 1mm wide at a 30 degree angle to the tire and 2" long. I have had three rear tires do this and was told it was nothing to worry about but never did get a good explanation why. The first one they said was debri on the track
Stop by and talk to Moose. You don't seem to want to belive the tire guys but you want someone on BBS to give you the answer.
If i got the same answer from every Pirelli person I asked I'd wouldn't have made that comment. And no I wasn't looking for the answer from "someone" on the BBS unless that person is a rep from Pirelli and will take the time to clear up some of the questions people have. Your response kind of implies that everyone in this thread is an idiot for asking tire questions here or discussing it:tut:
