Vertical Load

Vertical Load

In this video I introduce the topic of vertical load and  how it relates to traction. While always in flux, it’s important for a driver to be familiar with the concept of varying levels of grip.

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Video Transcript

Hey everybody, Matt Covert here again from howtobecomearacecardriver.com. And in this video we’re going to talk about something called vertical load. And much earlier in the series, during the weight transfer video I made the claim that weight transfer is the most fundamental part of racecar driving knowledge. Because pretty much everything is tied into it. And this is a huge concept that has everything to do with how weight moves around a vehicle.

So let’s take a quick look at what vertical load is. Vertical load is the perpendicular force, well, a force perpendicular to the ground, which is applied to a tire. Alright? terrible drawing, but that’s OK. Perpendicular force applied to the tire. And I think in the weight transfer video we used an example of a two thousand pound racecar. And let’s say if the weight was static, that means that this tire would be experiencing a vertical load of five hundred pounds. If there are four tires, five hundred pounds a piece, that’s pretty easy math.

Alright? That’s just static weight distribution. So vertical load, it’s’ important to understand that vertical load is constantly changing. And there are a number of reasons that it will constantly change.

We’ll just take a look at a couple examples. A lot of really high-tech racecars they use aerodynamics, which is just the concept of air bouncing off some type of downforce device. And when you add extra downforce to a tire, we’ll go back to this example, let’s say this is a rear tire and let’s say that there’s a wing on the back and it’s getting a huge amount of downforce from air bouncing off it. Well say this tire suddenly has six hundred and fifty pounds of vertical load on it now, simply because you’re going faster and creating that downforce, you’ve changed the tire’s vertical load.

Alright? Let’s go back here and talk about another one. Elevation change. Let’s say you’re coming off a straight and going into a section that goes uphill. Then when your racecar gets to about here it’s going to experience kind of a compression in the suspension because as it goes up the car is trying to change direction but it has momentum forward and it doesn’t want to. So your car is actually going to have more downforce right in this area. Alright? And just the last example, any time there’s more weight or downforce over a tire it has a higher vertical load.

Probably the most important one to understand about vertical load and how it changes is driver input. And this is really important because let’s just say you’re accelerating out of a corner and you hop on the throttle a little too soon. Alright? We talked about that in the weight transfer video. That’s going to make the rear end heavy and the front end lighter. Well when the front end gets lighter, these tires in the front are going to experience a smaller vertical load. Alright? Less weight over the front means less weight pushing down on the surface. Pretty easy to understand.

Now that’s also important to understand when you’re braking or going into a corner or anything like that. OK? Not a hard concept to get but it’s very important because when a tire has less vertical load, let me write that out, less vertical load equals less grip. So let’s go back to that example real quick where you’re coming out of a corner and accelerating. Because this has less vertical load, this tire has less capability to corner. So if you hop on the throttle too soon and you’re still trying to come out, track out of the corner, you might experience some understeer. And that’s something else we’ve talked about too.

So it’s really important to understand what vertical load is and that it’s always in flux. Whatever you do, any input you make into the car is going to effect vertical load and you have to understand that because is something else, and I know I’m always saying this too, this is something else that the driver can control. And the more you can control the vertical load on your vehicle you’ll know where all the grip is and you’ll know how to use that to your advantage. And that’s very important.

Alright I’m going to end there. Another technical video in the books about vertical load, glad we got that one out of the way. Please subscribe to the YouTube channel, you’ll never miss another video. And speaking of which, I’m probably going to make another one right now.

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