How To Find Your Optimal Tire Pressures
In this video I reveal an easy and effective way to dial in your racecar’s optimal tire pressures. If you don’t have a system, you’re just guessing.
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[Optimal tire pressures] Hey there again everyone, Matt Covert here again from howtobecomearacecardriver.com. I am particularly excited to share this video with you because it’s a strategy I used all last year, it worked really well for me. It’s something that I got from Ross Bentley, who is a racecar driver, instructor, and motorsports mentor. Totally knows what he’s talking about. He has some great books. If you haven’t read them, you should. And we’re just going to jump right in here because this is some really valuable information.
OK? I race a lot of autocross, as you probably know by know. You don’t see a lot of people out there taking tire data, recording it, making a new plan, and creating a better racing program for themselves. And if you use this method to find your optimal tire pressures then you’ll be ahead of everyone else, I promise. OK?
So you’re out there on the track. Maybe you your car’s not performing as well, you have a new car or new tires, how do you find your optimal tire pressures? You can do it by guessing, it takes a lot of time. But this method will really kind of shorten the process and take a lot of headache out of your racing program.
And in the last video we talked a little bit about what tire shapes produce the most amount of grip and what over inflated and under inflated tires look like. And we’re going to use that information in this video too so I’ll link back to the last video and we’ll get started here.
There are a couple things you need to acquire to use this method. One of this is some tool to measure tire temperature. And I recommend a pyrometer, a digital pyrometer because there are direct contact types. But I’ve used them and they don’t don’t work well. There are a couple reviews on a pyrometer that I use in my racing program and I have a review that I’ll link to on the website. So you need a digital pyrometer, you’re probably in the in the thirty to fifty dollar range for one of those, not too bad. I’ll just notate that right here. Thirty to fifty. So that’s not bad.
You’ll want to have a tire gauge, again not a big deal. I probably spent about ten bucks on the one I’m using. It’s digital too, I like those, they’re simple and easy to read.
And the other thing you’ll want to have on hand is to have an air compressor to make adjustments as necessary. I spent about fifty bucks on one of those as well, a really nice metal unit from Husky. And I think there are reviews on all of these things up on the website.
OK so once you have these things we can jump right in to what to do with them. So the first thing you want to do is get out on the track and make a run, do whatever it is you do and then come back in to the pits or starting grid or wherever you are. Oh let me redraw that. Whoops, boy, all over the place today with this. OK that will work, we can work with that. OK so you’ve just been out on the track and you come back in and your tires are starting to get warm. All that friction is causing them to heat up OK?
This is what you need to do, you need to take your pyrometer and take a temperature measurement here, here, and here. Inside, outside – inside, outside, center. And what we’re looking for, and we’re going to use some theoretical numbers for this, what we’re looking for is three equal temperatures. And I’m going to use degrees Fahrenheit for this. We’re looking for three equal temperatures, OK? That’s an indication that each section of the tire is being used equally and is generating the same amount of friction, which produces the same amount of heat and that means that you have an equal amount of grip all the way across the tire, OK?
The whole tire is touching the ground and you have created the optimal contact patch. This tire pressure is correct and you’ll want to record all this data so you can use it on similar days and similar temperatures and all that other stuff.
So let’s take a look at a situation that is not ideal. Let’s say you go out onto the track and you come back in and you’re looking at, you get readings something like this. So you’re taking one here, here, and here. Alright? The center tread is hotter than the outside and inside treads, OK? And that means that the tire is probably over inflated, because the shoulders of the tire have been lifted off the ground and they’re not producing as much friction and they’re not producing much heat, and this is not an optimal contact patch.
This means that you need to drop some air out of your tires, this is what Ross Bentley says, and I’ve heard this other places as well. You’ll want to, as a rule, one PSI per five degrees Fahrenheit, alright? So this tire, in theory, is two pounds higher than it should be to produce optimal grip. So if we drop two pounds out of this tire and make another run we should be able to see more equal temperatures after the next run. OK?
Now let’s go the other direction real quick while we’re here. Oops. Alright. So let’s say we have an under inflated tire, and this is the type of tire that tends to bulge out at the sides. Oh boy, I really need to get better at this whole thing. There we go, that’s close enough. Let’s say that this time you have hot temperatures on the outside but the middle is cool this time. Alright? Under inflated tire, center tread starts to lift off, that makes sense. And we can use this information to determine that the tire is under inflated. So if we use our one PSI per five degrees Fahrenheit we can see that this tire needs two PSI to come back into an optimal range.
This is something that I did all season long after every single run on every single tire. And it really cuts down the process of trying to guess and figure and talk to other people and going to go ahead and make another slide here because this part is really important. OK?
People have a tendency to make a lot of guesses. But I don’t understand why they would do that when they can base their decisions on data. This is another whole video right here, maybe I’ll make another video about this. But guessing versus data, there’s just no comparison. Data is going to win every single time. Why make all that extra effort for yourself and waste all that time, trial and error when you can just use hard numbers to make good decision for your racing program?
And that’s what this tire program is all about. It’s getting you into the sweet spot as soon as possible so you can get out there and have maximum grip. And I probably will make another video about that because I use a great data system, as well as this tire system, I use Harry’s Lap Timer, an iPhone 4, and a couple video cameras to collect a lot of great data.
I am going to make another video about that, that’s really important. So that’s coming up at some point. Until then, if you haven’t subscribed to this YouTube channel, there are always new videos coming out. If you find these videos helpful, shoot me a comment down below or if you have any questions shoot me a comment I love talking about this stuff, so I’ll put a link up here to the YouTube channel and I will be back shortly with another video from howtobecomearacecardriver.com. Until then please take care.