05 cayuse Posted July 3, 2006 Share Posted July 3, 2006 My Mustang currently has Pirelli Zero Neros. Max pressure is 51 lbs. I've been running them at 34 lbs, but wonder what pressure should I start with in deteriming what works best during "open track"? Thanks Quote Link to comment Share on other sites More sharing options...
Mr PS Posted July 5, 2006 Share Posted July 5, 2006 Are you running 34psi hot or cold? One way to determine is to check the temp profile of the tires. Some folks use the other general rule of thumb for street tires to be around 40psi hot or so. But the weight of the car and the driving style determines how hard the tires work on the track too. Quote Link to comment Share on other sites More sharing options...
granracing Posted July 5, 2006 Share Posted July 5, 2006 What MR PS said about 40 psi hot is a good starting point. The other thing you can do is look at the sticker on your door and see what it states as the max pressures. If 34 psi is the hot temp, it's too low. Quote Link to comment Share on other sites More sharing options...
GAC Posted July 5, 2006 Share Posted July 5, 2006 Every track is going to be different. Every car is going to be different, depending on what it weighs, how its suspension is working, how much camber you have, etc. The only real way to know is to take tire temps. I've run Falken Azenis, but on my car never had them over 35 psi hot. Quote Link to comment Share on other sites More sharing options...
mcmmotorsports Posted July 6, 2006 Share Posted July 6, 2006 The only real way to know is to take tire temps. I've run Falken Azenis, but on my car never had them over 35 psi hot. Yes, this is correct. Taking tire temperatures are the ONLY way to correctly know how much air pressure you should be running. :edit: The ONLY way I have ever been taught. In this example, the left front is underinflated. You can tell this by how the center of the tire is cooler than the inner and outer edges. Increasing the air pressure on the LF will bring up that center temp. Also, this car could benefit from a little more positive camber on the LF to help with the hotter inside temp. The RF needs a little more negative camber and I would leave the air pressures alone on this until we saw what the temps looked like after the camber adjustment. The RR is overinflated, dropping the air pressure on the RR might also even out the temps across the surface of the tire. The LR needs maybe a pound or two reduction in air. Hope this helps.....nice to know some of my oval track experience is going to transfer over to this twistie stuff. Quote Link to comment Share on other sites More sharing options...
white_2kgt Posted July 6, 2006 Share Posted July 6, 2006 Tire temps help, yes, but keep in mind that the only way tire temps are going to be even across all tires is after a good skid pad session. Best way to set tire pressure is get it close w/ the methods above, then fine tune by seat of the pants. You'd be suprised that after driving for a while you can really tell a difference in tire pressures. Quote Link to comment Share on other sites More sharing options...
mcmmotorsports Posted July 6, 2006 Share Posted July 6, 2006 Tire temps help, yes, but keep in mind that the only way tire temps are going to be even across all tires is after a good skid pad session. That does make sense, I forgot about the fact that we go left AND right now. Quote Link to comment Share on other sites More sharing options...
05 cayuse Posted July 7, 2006 Author Share Posted July 7, 2006 The 34lbs was cold temp before 1st session. Since I bought these tires as "take-offs" I didn't get owners book. You folks sure enlightened me! When taking temps of tires, what thermometer type are you using to get temps? Quote Link to comment Share on other sites More sharing options...
mcmmotorsports Posted July 7, 2006 Share Posted July 7, 2006 Either a probe type Pyrometer like this: http://cgi.ebay.com/ebaymotors/NEW-LONGACRE-TIRE-PYROMETER-50635-REPLACES-THE-50630_W0QQitemZ220004904800QQihZ012QQcategoryZ107068QQrdZ1QQcmdZViewItem#ebayphotohosting Or an infrared type like this: http://cgi.ebay.com/ebaymotors/LONGACRE-AccuTech-Infrared-Laser-Pyrometer-500-50611_W0QQitemZ220004905142QQihZ012QQcategoryZ107065QQrdZ1QQcmdZViewItem#ebayphotohosting I prefer the probe type, but the infrared can be usefull for brake temps and other uses as well. Quote Link to comment Share on other sites More sharing options...
white_2kgt Posted July 7, 2006 Share Posted July 7, 2006 Get the Probe, the IR is useless for the most part. Quote Link to comment Share on other sites More sharing options...
granracing Posted July 7, 2006 Share Posted July 7, 2006 For a beginner/intermediate driver, just worry about getting the tire temps fairly close. Ask instructors who are familiar with similar cars what they'd suggest. Eventually, you'll find a tire pyrometer (as the last post states, probe only!) to be useful. But if you ever really get into this stuff, it gets even more confusing. Based on what I've learned so far, and I have much more to learn before I understand it better, tire temps are relyed upon heavily for certain types of tires (usually slicks) or if doing longer endro types of races. In sprint races (or HPDE sessions), this data is not as useful to fine tune the camber/tire temps. Again, just stick to the basics for now but thought this stuff was very interesting (but confusing!!). Brock Yates just recently released a book on race car dynamics / tuning. I didn't get much time to go through it (yet), the book also confirms what I've been hearing about not relying on a pyrometer to "get it right". Others have told me this before, but much of the tuning is based on how the tire is wearing. In Mr. Yates' book, he discusses this (it's the first I've personally seen this tuning method in a book). Quote Link to comment Share on other sites More sharing options...
Eric J. Posted July 7, 2006 Share Posted July 7, 2006 Get the Probe, the IR is useless for the most part. It's useful for engine/radiator/brake/etc. temps, but it's useless for tire temps. The probe type pyrometer is the only way to get reliable tire temps. The IR just measures surface temp, which can change very quickly and won't be representative of the tread/carcass temps. You need a probe to get down in there and see what's really going on in the tire. Quote Link to comment Share on other sites More sharing options...
white_2kgt Posted July 7, 2006 Share Posted July 7, 2006 Get the Probe, the IR is useless for the most part. It's useful for engine/radiator/brake/etc. temps, but it's useless for tire temps. All of which can be done w/ the probe type as well . Quote Link to comment Share on other sites More sharing options...
GAC Posted July 7, 2006 Share Posted July 7, 2006 In sprint races (or HPDE sessions), this data is not as useful to fine tune the camber/tire temps. This is not really true. If you're hot-lapping and you come off with hot tires and have a pyrometer at the ready to take temps ASAP, you can certainly tell if a tire is crowning or bowing at the center and whether you need to take air out or put more in. A tire pyrometer is one of the most cost effective ways to spend your money to enhance grip and reduce lap times. Kenny Brown has some good thoughts on the matter if you're curious to find out more. Quote Link to comment Share on other sites More sharing options...
Dave Jones Posted July 9, 2006 Share Posted July 9, 2006 Brock Yates just recently released a book on race car dynamics / tuning. I didn't get much time to go through it (yet), the book also confirms what I've been hearing about not relying on a pyrometer to "get it right". Others have told me this before, but much of the tuning is based on how the tire is wearing. In Mr. Yates' book, he discusses this (it's the first I've personally seen this tuning method in a book). Carroll Smith wrote the same thing years ago in one of his books -- pretty sure it was "Tune to Win." Temps may get you in the ballpark, but you should pay more attention to the appearance of the tire surface. Also FWIW, if you already own a DVM with a thermocouple input (pretty common nowadays), you can get the penetrating tire probe from MSC Industrial Supply for about $42. http://www1.mscdirect.com/CGI/NNPDFF?PMPAGE=4579 HTH, Dave Quote Link to comment Share on other sites More sharing options...
granracing Posted July 13, 2006 Share Posted July 13, 2006 Kenny Brown has some good thoughts on the matter if you're curious to find out more. I'm curious! Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.