On average, Radio Control (RC) Car tires need to be replaced every three months, though this will depend on how often you drive them. Still, understanding what measurements you’ll need to replace the tires is vital; otherwise, they won’t fit, and the RC car will be difficult to drive on short courses.
Here’s how to measure your RC tires in just a few simple steps:
- Determine the ideal rim and tire size.
- Find a digital caliper, plastic board, and flat surface.
- Use the digital caliper to measure the rim width.
- Measure hex slot depth with a caliper and plastic board.
- Use these measurements to calculate the offset.
- Note down the offset.
In this article, we’ll provide you a simplistic breakdown of how you can measure and select the ideal RC tires for your RC car.
How to Determine the Ideal Rim and RC Tire Size?
When it comes to measuring your RC tires, you must measure them correctly so they will properly touch the ground. If you don’t get an accurate measurement, the RC car will struggle to ride across different terrains.
However, the ideal rim and tire should be on scale with your RC vehicle. If your car is 1:10 or 1:8 model, then find the corresponding sizes for tires, as recommended by the manufacturer.
Here are some basic guidelines to consider when selecting your rims and tires:
- Most 1:10 buggies have standard 2.2 inch (55.88 mm) rims and wheels, though the front and back wheels are not the same widths.
- Most 1:10 trucks have the same rim and tire sizes as buggies.
- Many 1:10 short course cars have different diameters on the outside and inside.
- 1:8 buggies are more standard and have the same size rims and tires on the front and back.
- Hex mounting is the most common and will usually be 0.47 or 0.55 inch (12 mm or 14 mm) rims.
You can make sure that the rim size will fit onto your RC tire by measuring the offset, which we’ll discuss below.
How can you Measure RC Tires?
Although you should be able to follow the manufacturer guidelines to choose new rims and tires, it’s always best to measure your RC tires to be sure you get the next fit. This will be especially true if you buy second-hand, as some modifications could have been made.
1. Find a Digital Caliper, Plastic Board, and Flat Surface
Before you start measuring, you’ll need a handful of equipment:
- Digital caliper, like this Neiko 01407A Electronic Digital Caliper from Amazon.com
- Small pieces of plastic board or any stiff material that won’t bend or break easily
- Flat surface with good lighting
A digital caliper will be so much more precise than anything else you could use – such as a measuring tape or ruler. Plus, they’re not overly expensive and can be used for a number of projects.
2. Use the Digital Caliper to Measure the Rim Width
When measuring the width of the rim, you’ll need to measure the whole diameter before dividing that number to find the radius.
Start by placing the caliper next to the tire to measure the entire width of the rim. Once you have that measurement, divide it by two to find the radius of the RC tire.
This is the measurement you’ll want to write down.
For example, if you have an RC tire that measures 20 mm across the width, the radius would be 10 mm.
3. Measure Hex Slot Depth with a Caliper and Plastic Board
Now, you’ll need to measure the depth of the hex slot.
To get this measurement, use a flat piece of plastic or cardboard – as long as it’s a sturdy piece of material that doesn’t bend, it will work.
Place the flat piece of material over the rim’s inner side. Once you have the width marked, measure the distance on the plastic using the digital caliper. You’ll also want to take that measurement and subtract the width of the plastic board.
To do this, measure the board’s width and subtract it from the total measurement you just took. For example, if the total length was 20 mm and the board’s width was 3 mm, the remaining size would be 17 mm.
4. Use These Measurements to Calculate the Offset
Now that all three measurements are taken, you’ll need to calculate the offset.
The formula for calculating the offset of an RC tire is as follows:
The Radius of Tires - Depth of Inner Mounting Hex = Offset
So, you’ll need to measure the left tire and the right tires. Once you do that, you’ll have the offset and will be able to select your tires based on that measurement.
What Is Offset?
Measured in millimeters, the offset of an RC tire is the distance from the mounting surface of the hub to the wheel’s centerline.
To calculate the offset of an RC tire, you’ll need to measure the radius of the tires and the depth of the mounting hex. Once you have the offset, you can then determine what the wheel offset is.
There are three main types of wheel offsets:
- Positive offset. A positive offset occurs when the hub mounting surface is positioned towards the front or sides of the wheel. When the RC tire has a positive offset, it’s likely because it’s a front-wheel-drive car.
- Negative offset. A negative offset occurs when the hub mounting surface is positioned towards the back or brake side of the centerline.
- Zero offset. A zero offset occurs when the hub mounting surface is aligned with the centerline of the wheel.
Why Does Offset Matter?
Offset is a critical aspect to calculate because it influences how far away the tire will be from the vehicle. Because of this, the tire will affect how well the RC car can travel on different terrains.
In addition, getting a new set of tires with the wrong offset can cause significant damage. If you don’t find this measurement, you may find your wheels rubbing against the side of the car or the suspension.
A positive offset will generally cause the wheels to be further away from the chassis, positioning the tires further from the car. When this happens, the tires will be wider and allow the vehicle to have better traction and run stability.
On the other hand, a negative offset will be positioned oppositely. This causes the car to have enhanced steering and allows for enhanced precision on track courses.
Why You Can’t Look Up RC Tire Sizes
When you’re working with full-sized tires, they often have a size engraved on the side of the wheels. This makes finding and replacing them very easy. However, RC tires don’t have this feature.
Many manufacturers tend to use interchangeable parts and make size matching almost impossible. The only method you can use to change an RC tire accurately is to either measure it yourself or select one using your user manual.
This YouTube video by AMain Hobbies explains what you’ll need to do to select the right tire for your RC car:
Frequently Asked Questions
Can you measure using a ruler?
No, you shouldn’t measure your RC tires using a ruler because a few millimeters can highly impact how the wheels function. Getting the wrong measurement will result in an error, and the car won’t perform at peak performance.
Do I only need to measure one tire?
Depending on the car model, you may need to take measurements of both the front and rear tires as some RC cars are front-wheel or four-wheel drive. Depending on this factor, the tires may have different width rims. However, these models are generally only rock crawlers or large rear-wheel rimmed cars.
What is the difference between 1.9 and 2.2 wheels?
The numbers refer to the diameter of the wheel and the inside diameter of the tire. The 2.2 tires are a bit larger than the 1.9 tires.
Can you use 1.9 tires on 2.2 wheels?
Yes, you can use a 2.2 wheel in a 1.9 tire
Are there different types of wheels?
There are four main types of wheels, including buggy, truck, short course, and Truggy. Aside from that, there are two main types of RC buggies: a 1:10 and 1:8 scale