The Ultimate Guide on Car Tyre Grips (Unknown Tyre Secrets)

I swear you have been quiet about the secrets of the tyre group for Chuseok. We are talking about larger, wider tyres, sir. Seriously, when your hands feed knocks me out, it brings me here because you want to know why wider Bridgestone tyres Corby and more YouTubers did it wrong on the top. You’ll say water.

It's described by f equals mu and the surface area of the contact patch. Well, it has nothing to do with it. We've mentioned this in previous videos, Hamilton's law of friction.

Common Misconceptions about tyre Grip

Yeah, but do I really have to crack that? I really like those guys and their YouTube channels. Besides, this is a common misconception about photos witchable.

Secret Artwork Revealed

Right, wait, what is he doing? Oh, he's just checking how scratch or since the painters. That’s all. You’ll be fine, okay. Calm down now. I’ll give you what you want. Tell us the dark secret artwork. Okay, it all starts with how rubber generates friction.

Why the Confusion About Rubber Friction?

So why is there confusion about how rubber friction works in the first place? So, finally we are here to the equation: friction force equals mu, or the coefficient of friction times the normal force. This looks like I am reading my high school book. 

Conducting an Experiment on Friction

Let’s figure out an experiment. If we take this piece of cardboard and put it on a glass table, and apply some load to it, and try to pull it across the table. Guess what will happen? This is going to require a certain amount of force. 

Imagine If we cut out a smaller piece of this cardboard and conduct the same experiment. Now what will happen. It will require the same amount of force to pull it across the table. So yes, Indeed, the friction force in this case is independent of the apparent area of contact.

The Problem with Cardboard and tyres

However, there's a big problem here which most of you will not notice. You may think what the problem is? Well, cardboard is not the same material as tyres. Yes I know it's obvious. Tyres are made out of rubber. Say we conduct the same test as we just talked about, but with a rubber block. 

So what do we do now? We take the rubber block, put it on top of a glass table, and apply some weight on it. And the following process is the same as usual. Try to pull it across the table. So in other words, Antone's law of friction is not that helpful when trying to understand rubber friction.

Rubber Adhering to Tarmac

How does rubber adhere to the tarmac? Well, a hypothesis is that as a result of momentary molecular bonding between the rubber and its harmonic, the more area in contact, the larger the adhesive forces, and thus more grip. 

So a larger contact patch provides more grip than a smaller one because real surfaces are really rough on a molecular scale. Contact between the tyre and the tarmac is limited to the highest bumps on each of the two surfaces. If we apply more vertical load on the tyre, this increases the area of contact, providing more grip.

Mechanical Keying and Deformation

Also called mechanical keying, this happens when lateral and vertical loads on the tyre cause sharp bumps in the tarmac to penetrate the rubber. This generates friction. When deformation forces are high enough, the rubber starts to tear. Anyone who’s been on a racetrack has probably seen this phenomenon before.

Viscoelastic Nature of tyres

Another important aspect we need to understand about tyres is that they are viscoelastic, meaning that tyres conform to bumps and surfaces, but they do not fully rebound after deformation. Try to push your fingernail into a racing slick and you will find that the mark will stay there for a long amount of time. Now, do the same thing with a road tyre and you're going to find that the mark will disappear almost immediately.

Race Slicks vs Road tyres

So why is there a difference between race slicks and road tyres? Well, race slicks are generally made from what’s called high hysteresis or high energy loss rubber. High energy loss rubber generally generates more grip because the highest air as rubber deforms because of mechanical keying generates a shape that resists sliding better than low hysteresis rubber, which results in higher friction forces.

Understanding Rubber’s Load Sensitivity

Remember, we said that as the vertical load increases on the tyre, the area of contact increases. So in other words, as you load up the tyre vertically, you will not see a one-to-one gain in tyre friction. 

A simplified explanation to this is that as the rubber deforms into the tiny bumps on the road, it eventually reaches the bottom, meaning the contact patch is as large as it can be and cannot generate more friction. This also explains the diminishing rate considering the way the contact patch grows.

Tyre Operating Temperature and Texture

As you probably already know, Tyres Corby has what is called an optimum operating temperature. The temperature affects how soft the rubber is and thus how well it adheres, deforms, and tears on the tarmac, heavily influencing the amount of available grip.

We talked about how the rubber is pushed down into the tiny bumps on the road surface. This will also be affected by the shape and variety of those tiny bumps. 

Yes, of course, the texture of the tarmac affects how the rubber adheres, deforms, and tears. Practically, this influences what compound would be used for different tracks. Manufacturers of race slicks usually have a recommendation for which compound fits what roughness of the track surface.