(047) Molecular Adhesion

In this video I tackle traction on a microscopic level. While many parts of molecular adhesion go beyond the scope of piloting a racecar, I still believe it’s a great concept to have in your arsenal. 

Molecular Adhesion – Video Transcript

Hey everybody, how you doing? Matt Covert here again here from howtobecomearacecardriver.com. And it this video we’re going to talk about something called molecular adhesion. And I know it sounds complicated but I promise it’s not. We’re going to break it down step by step. It’s going to be really easy. This molecular adhesion thing has to do with how your tires grip the racing surface. So let’s jump right in on molecular adhesion.

So if you know anything about autocross you know that the UTQG tread rating, sometimes just called tread wear rating, is just a signification of how soft a tire is. And if you don’t know that you know that a lower UTQG tread rating equals more grip. And you know that one with a higher one has less grip. And that’s really all we need to know. Everything beyond this is kind of gee whiz stuff. But always maintain that the more you know – all those little tiny things that fall into the more you know category – you know all that gee whiz stuff. It adds up to very intelligent driving. And that is what we’re after here at howtobecomearacecardriver.com is intelligent racecar driving. So let’s break this down a little further and see what it looks like on a molecular level. See how I did that? Molecular adhesion. Let’s do that.

So let’s take a super tiny section of the driving surface. And we’ll blow it way up so it looks something like this, OK? And let’s just – we’ll start one side of a tire here. I’m just going to make these little marks that signify that they go way farther than this but we’re just taking a little chunk out of it.

So this is the driving surface. And these are – well, a section of a tire. Alright. So let’s take a look at a tire with a higher UTQG tread wear rating. We’ll just say that’s higher. A higher rating means that the tire is a harder tire. The compound is not very soft and it’s probably built for street use or highway driving. Something that will last a very long time. And so the harder you pack a rubber the longer it will last because it’s less resistant to wearing down when it’s moving across another hard surface. Obviously, that makes sense, OK?

So a tire like that is not very pliable, it doesn’t bend easily because it’s so hard, OK? And the result is kind of this. You kind of get to fill in some of these gaps. OK. But that’s kind of what’s happening here. Like that, OK? Because the tire is so hard is just can’t fill in all these little imperfections in the driving surface as it’s rolling or sliding across it. And so the result is all these little pockets of unused contact patch. We’re always talking about contact patch. And this is a big deal because the entire point of suspension and racecar tires is to maximize this patch. You can see there are a lot of little places that just aren’t helping us at all. OK?

So let’s go ahead and look at something that has a lower UTQG tread wear rating. We’ll make that similar driving surface, something like that. And we’ll get another tire section started here. And again this is on a super super super minuscule scale. And that’s why we’re talking about molecular adhesion on a really tiny level. A soft – let me back up. A UTQG tread wear rating that is lower means the tire is softer. It’s more pliable. And as such, it can conform to the road surface a lot easier. It bends easier, it tends to fill it the little gaps better and you can see the result immediately on a microscopic level the tire is actually – genuinely conforming to the road surface.

And now you’ve maximized your contact patch. That is exactly what we want. All this stuff is ridiculously complicated. I don’t claim to know all the physics involved with this. It goes way beyond this. But this is a really cool visual to show you why a lower rated tire – lower UTQG tread wear rating is better for racecar driving.

Alright so there you have it – molecular adhesion. I think that’s all we need to talk about. Go ahead and click that little box that’s right down there in the corner. You can subscribe to the channel right through there. You’ll never miss another one of these really cool videos ever again. And I’m going to go make another one. And I’ll be back soon from howtobecomearacecardriver.com.

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