Grip – as racers, we’re all chasing it. But where does it actually come from?
At the most basic level, your car gets grip from its tires touching the track. The more of your tire that is touching the ground at any given time, the more grip your tire can create.
The area of your tire that is touching the track is called the “contact patch.”
To help you visualize the contact patch, I placed this tire in flour.
The flour sticks to the portion of the tire touching the ground.
That area is the tire’s contact patch in this situation.
VISUALIZING THE CONTACT PATCH
At first glance, the concept seems simple enough – maximize your contact patch and get a lot of grip.
But the challenge we have as racers is that the size of your tire patch changes as you go around the track.
Think about what happens when you go into a corner – the weight of your car transfers towards your outside tires. As that happens, it changes the angle of the tire.
That change in angle will change the size and the shape of your contact patch – and with it the amount of grip the tire is producing.
Because of that, you want to setup your car in a way that will give you the most favorable tire patch possible.
Your contact patch changes as you go around the track.
That means you have to make some decisions:
- Where on the track do you want to have maximum grip?
- And where on the track are you willing to sacrifice some grip in order to have more grip somewhere else?
With camber, you will always have to sacrifice grip in one area of the track to gain it in another.
What is Camber?
To get the most favorable contact patch, you will need to change the angle of your tires.
The angle of your tires relative being straight up and down is called camber.
- If the tire is sitting perfectly vertical, that would be considered 0 degrees of camber
- If the tire is leaning towards the inside of the car, that would be called negative camber
- If the tire is leaning towards the outside of the car, that would be called positive camber
What is Our Goal With Camber?
We’ve already talked about this concept at the most basic level – the bigger your contact patch, the more grip you will have.
In an ideal world, we would love to have the maximum contact patch everywhere.
But since your contact patch is changing in size and shape during every lap, that means you have to make some choices.
You have to decide where on the track you want to have the maximum contact patch and where you can afford to have a slightly smaller contact patch.
As a general rule, racers choose to set their camber at an angle that will give them their biggest contact patch in the middle of the corner.
The middle of the corner is the point of the lap when the car is demanding the most grip out of the tire – and when a big contact patch is most necessary.
Camber isn’t about maximizing grip on every part of the track.
It’s about prioritizing grip in the areas of the track that will demand the most out of our tires.
On the other hand, when the car is on a straight away, we aren’t pushing our tires to the limit. Because of that, the car can afford to have a smaller contact patch and still handle well.
So the goal is this – we want to set our camber at an angle that will give us the biggest contact patch in the areas where we need it the most. To get that, we are willing to sacrifice grip in areas of the track where it’s not as necessary.
How to Measure Camber
Measuring camber is very straightforward. All you need to do is:
- We want to make sure the battery is in and the car is race ready because we want a measurement of what the camber will be while the car is on the track
Camber changes slightly as the suspension compresses.
Always measure camber with the battery installed and the car in race-ready condition so the suspension sits at its normal ride height.
- Sit the gauge on a flat surface and slide it so that the lever is sitting flush against the tire (the lever should be touching both the top and bottom of the tire)
- Set the gauge gently against the tire – don’t push. If you push you could get an incorrect measurement
How to Adjust Camber
Now that you know how to measure camber, we can adjust it to get the angle of your tires exactly where you want it.
To change the camber, all we are going to do is shorten or lengthen the camber link.
Changing the length of the camber link will move the top of the tire in or out – which will change the angle.
Finding the Camber Link
Look down at your car from overhead. You should see a link that connects the bottom of the shock tower to the top of the wheel assembly.
That is your rear camber link.
If you go through the same process while looking at the front of your car – you should see your front camber link.
But be careful — there are usually two adjustable links on the front of your car.
You don’t want the link that connects to your steering.
If you move a link left or right and the tire turns, that’s the steering link. Leave that one alone for now.
The camber link moves the top of the tire in or out — not left or right.
Turnbuckle Wrenches
As with everything in RC, adjusting your camber angle is a lot easier if you have the proper tools.
In this case, you’re going to want to get a turnbuckle wrench.
A turnbuckle wrench is designed to fit the flat section in the middle of the links on your car.
You could use a pair of pliers or a small wrench in theory – but doing it that way makes everything much more difficult and it marks up your links.
To adjust your camber, place the turnbuckle wrench over the flat part in the middle of the camber link and rotate it toward the front or the rear of the car.
Turning the wrench one way will make the link longer.
Turning it the other way will make the link shorter.
Unfortunately, the only way to figure out which direction makes which adjustment is to turn the link one way and see whether the tire moves in or out.
Once you know which way to turn the link to make the adjustment you want, alternate between making small adjustments and then re-measuring until you get the tire to the angle you’re looking for.
Now What Do I Do With All This?
At this point you should have a solid understanding of the basics of camber.
But there’s still one big question you probably have that hasn’t been answered – how do I know what camber adjustments to make while I’m at the track?
That’s why the next post in this series is going to answer that for you. It will go over how to tell when your camber is off during a race and which adjustments will correct it.