Last week I was invited to Clash Miami to run a wheel pit for the pro races. To make a long story short, Clash Endurance created a triathlon series that takes place on Nascar track. I was on site at Homestead-Miami Speedway, host of Clash Miami, with a number of FLO wheels incase a pro had a mechanical issue. We had an official FLO Wheel Pit that mimicked a Nascar pit stop, fire suit included! Ultimately, no one needed help but it was a lot of fun!
While I was on site I examined the track and worked with a number of athletes to discuss tire pressure on such a unique course. The track is rough with an exposed aggregate which allows cars to hold the corners. For triathletes, this means lower pressure than you are used to. We also discussed temperature and how it impacts tire pressure and aerodynamics in a track environment. I shot a video when I was on the track and recorded a podcast with a recap once I got back to the office. Take a look/listen to learn about tire size, pressure, etc, on a Nascar track and let us know your thoughts.
Setting Tire Pressure on a Nascar Track – YouTube
Setting Tire Pressure on a Nascar Track – Podcast
Video Transcript
00:00:00:17 – 00:00:18:17
Jon Thornham
Hey, I’m out here at Homestead-Miami Speedway for Clash Miami. I have an official fire suit on him in the FLO wheel pit for the pro races. If anyone has any issues, they come in. They can now swap their wheel out for a four wheel. We’re going to talk about a couple of things here today on a unique course like this, which is the speedway we’re going to talk about, the surface conditions, setting tire pressure.
00:00:18:17 – 00:00:35:24
Jon Thornham
I want to talk about tire size and tire width also a touch on some aerodynamics. So let’s check it out. What you’re going to see here is the track. So this is the track that the athletes go around. Pretty crazy bank on the other side there. What’s really unique about this course is it’s a NASCAR course and the pavement itself is actually medium to almost rough.
00:00:35:29 – 00:00:54:09
Jon Thornham
It’s got a pretty interesting texture. I’ll show you here in a minute. And this far south, what we can get, though, is a very extreme temperatures. You off to 136 degrees and was track temperature. We had a gun on this the other day and it’s 136 degrees. So as a rule of thumb, remember, for every ten degrees, you’re going to increase your tire pressure by about 2%.
00:00:54:24 – 00:01:19:19
Jon Thornham
So it’s very, very important that when you’re setting up for a race like this that you’re either accounting for that or you’re setting up in a temperature that is similar. Sometimes it’s not possible. So how do you adjust for that? If you can get to the temperature? We always recommend inflating outside, not in like a cold hotel room or something like that, but if you are outside and you know that it’s going to get hotter by the time you’re on the course, you can do the math and you can basically pressure down some.
00:01:19:29 – 00:01:42:02
Jon Thornham
That’s why something like the new FLO Air Gage is really beneficial for something like this. You can get very accurate tire pressures, ensuring that you are not going to over inflate for race like this. This here is the actual surface that you’re going to look at. Now I’m can put my hand down here so you can kind of get a scale for what this looks like, but you can see how there’s actually quite a few pieces of aggregate that are in here that are exposed.
00:01:42:14 – 00:02:03:07
Jon Thornham
Now, part of the reason for that is because, again, this is a NASCAR track. So as cars are coming through these corners, very, very high speeds, they do need some sort of durability on this track, some sort of roughness to make sure that they’re going to hold those corners. For an athlete like yourself, that’s going to become important because the rougher you get, the lower you’re going to want to manage that tire pressure.
00:02:03:19 – 00:02:22:21
Jon Thornham
So it’s important to adjust your tire pressure for these tracks. Now, if you’re wondering how do you set your tire pressure based on temperature? Is it air temperature or surface temperature? Great question. So one thing we always recommend, is it before you inflate your tires, if you can go out and you can make a few laps, what that’s going to do is it’s going to warm up the rubber on your tires.
00:02:23:01 – 00:02:37:26
Jon Thornham
It’s going to get you closer to the actual consistency that you’re going to be when you’re racing. Now, the second thing you want to consider is your tires are actually making some contact with the surface of the road. So they will warm up and it’s going to be closer to the temperature of the track as it is to the air.
00:02:38:08 – 00:03:00:29
Jon Thornham
So it’s not exact, but it is closer. So make sure you adjust based on the road surface temperature, not always just the air temperature. We have three FLO wheels here, all with different sized Continental GP 5000. This is a 25 millimeter tire, a 28 millimeters tire and a 32 millimeter tire. Now, it is important to know that when you’re riding a course like this, you want to size your tire properly.
00:03:01:10 – 00:03:18:21
Jon Thornham
So when you’re looking at tire size at a course like this, I’m going to get right down here on the pavement so you can see it. It is very rough based on the tires for NASCAR and to be able to hold these banks now from a tri perspective, you’re going to want to get the widest tire that’s going to fit your frame.
00:03:19:01 – 00:03:35:26
Jon Thornham
It’s important because some tires are too wide for certain frames. So you want to get the largest tire that you can that will fit your frame. Now for a FLO wheel 28 So to optimize aerodynamically, you can get away with 32s, but on a course like this, rolling resistance becomes very important because of the roughness of the surface.
00:03:37:19 – 00:03:53:06
Jon Thornham
So remember, on a course like this, you’re going to want to have your tire pressure set low enough so that you’re going over the bumps as as opposed to bouncing over them. So all those small pieces of aggregate, you don’t want to bounce up and down. That’s taking your watts that you’re putting in the pedals and moving you up and down as opposed to moving you forward.
00:03:53:21 – 00:04:17:24
Jon Thornham
Now, the best way to do that is to have a lower tire pressure. But the lower the tire pressure gets, the larger the contact that you get when you have a narrow tire, like a 25 millimeter tire, what happens is your contact patch gets longer and longer, longer under that under the tire, and it has some width to it, but not as much as a 32. A 32 because of its width allows you to have a shorter contact patch and a wider contact patch.
00:04:17:24 – 00:04:37:11
Jon Thornham
The area is the same underneath, but it changes the shape. Now a long contact patch like that causes issues because it’s harder to roll over that contact patch. Think of a moment you’re standing on your toes. It’s a lot easier to push you over than it is if you have skis on your feet. So we want to make that contact patch as short as possible to help with rolling resistance.
00:04:38:23 – 00:05:03:19
Jon Thornham
When you look at a wheel like this on the ground, you will see a smaller 25 millimeters higher as it rolls. It’s going to have to go over those bumps that aggregate in the period when you have a larger tire like a 32, we’ll see that it makes it easier to go over the aggregate and the pavement. What about aerodynamics and of course, like this?
00:05:03:19 – 00:05:22:28
Jon Thornham
Well, what’s interesting about this is it’s basically like a giant velodrome and you have a complete loop. So what’s unique is that because the walls are banked, as I look around here, you can see this, there is airflow in here, but in certain areas, it’s going to be a lot quieter and a lot. Stiller than you would have if you’re out in the open road.
00:05:23:11 – 00:05:43:13
Jon Thornham
The other thing you want to consider is that if there is airflow in one direction, you may be in a headwind in the other direction. Your tailwind so kind of balances itself out. Now, aerodynamics are still very important in a race like this. I’m not saying that they’re not. They’re incredibly important. But you also definitely want to take into consideration heavily the resistance because of the unique aerodynamic situation that you see in the course like this.
00:05:44:09 – 00:05:59:12
Jon Thornham
All right. Let’s do a quick recap. So in a course like this, make sure that you’re getting out early, setting your tire pressures, maybe with a lap or two so that you’re accounting for the temperature and make sure you understand what the temperature can be later in the day when you’re actually racing 2. because of the surface like this, that is rougher.
00:05:59:12 – 00:06:14:24
Jon Thornham
We have some aggregate this exposed. We’re going to want to make sure that we’re going to have a tire size that is wide enough. It’s going to allow you to get lower going up pressures where you’re optimized around the rolling resistance, which really great about this is it’s very well taken care of. So you’re not going to hit something like a pothole.
00:06:14:24 – 00:06:31:16
Jon Thornham
You can get those lower pressures to make sure that you’re optimized for that again, aerodynamically. It’s very important. Still very important. So in something like this. But let’s focus a little bit more on the rolling resistance here because of the course and how unique it is and what’s not to make the tires too wide so that you’re blowing out the aerodynamics of your wheels.
00:06:31:28 – 00:06:48:00
Jon Thornham
Let’s make sure you’re using being smart about it and you’re going to optimize for those aerodynamics and rolling resistance. If you have questions about this, please feel free to reach out. We have tire pressure charts and everything here we can help you get set up with the right pressures, of course, like Homestead-Miami Speedway or Daytona later in the year.
Co-founder at FLO Cycling. Jon manages the day to day operations and acts as the lead engineer for all FLO products.