By Joe Rich
Table of Contents
RC Car Tire Measurements Explained
A RC car tire is the part of RC car steering system that comes into contact with the ground and transfers the different forces applied to it by the RC car suspension, engine, braking system and others.
How do I choose RC wheels?
RC wheel selection can be daunting. RC wheels are not all created equal which means you have to know their characteristics so you get the perfect RC wheel for your RC car, truck, buggy.
Selecting RC wheels requires thought and research. Think about what type of surface you’ll be driving on – carpet, racing turf/grass-coated track, almost any terrain; or do you want more grip?
The right arena demands different tires! Another important consideration is the offset (width)of the wheel.
A common mistake for RC newcomers is to buy RC wheels or RC tires according to their body size without considering other features such as offset (also known as back spacing).
That means buying a set of wheels designed for off-road based on a vehicle built mainly for asphalt racing because most beginners do not know what offset really is…and why would they? Most RC wheel manufactures print this information in small print
The RC car tires measurement is a fundamental topic to know before buying RC wheels or RC tires; this will help you avoid any unpleasant and costly mistakes.
RC car wheel offset is the distance from the hub mounting surface to the centerline of the RC car tire tread face, in millimeters (mm). Offset can be expressed as negative, zero or positive depending on where it falls in relation to the RC car suspension setup
Every vehicle has a specific offset which is measured between two points:
1) RC wheel mounting surface
2) RC wheel center line.
On most RC cars this is simply where each axle shaft mounts to its respective RC car wheel/tire but some vehicles use an upper arm that attaches to the RC car hubs and therefore changes the RC wheel offset.
As a general rule, RC wheels with a positive offset have more grip than RC wheels with a negative offset as well as faster steering response; but also typically wear out RC tires faster because of the increased scrub radius (radius of where actual tire contacts road) that is created in front due to the axle being closer to the center line of the RC car tire.
An RC car with zero offset will not wear down their RC tires much or have very little wear.
RC cars with zero offset can be easily affected by weight transfer on acceleration or braking which means that they do not provide maximum grip even after many laps.
This is especially true if you’re driving RC cars on RC tires with very high grip racing RC tires!
When RC cars have negative offset they have more body roll than RC car with zero offset so there is a trade off between good grip and faster steering response. RC Car Tires Measurement
How are RC tires measured?
RC tires are measured by RC car tire width, RC car tire diameter, RC car tire circumference and RC car tire tread.
RC tires are measured in millimetres so you will have to convert inches to millimetres if the RC mode you are using only has inch measurements.
All RC tires can be converted to clear metric measurements for ease of understanding which is the most commonly used way because Metric units are just easier for people without an engineering background or experience with math conversions.
Many people use the recommendations from their particular manufacturer when measuring their RC tires but always keep in mind that these figures can vary depending on your RC car, RC car part manufacturer and RC car part style.
For example some RC tires come with different offset per RC car tire which can affect the overall RC performance.
The RC tire width measurement is measured in millimetres starting at the point where the tires rubber meets the wheel so not including any other measurements such as RC tire offset or RC tire sidewall.
There are many factors involved when measuring RC tires like offset, sidewall height, circumference etc.
To measure RC car tires, keep in mind that there are three main steps. When it comes to more accurate measurements, you should use a digital caliper instead of traditional measuring tools like ruler or tape measures.
We can use a digital caliper to measure the width of the rim. Once we have that measurement, it’s easy: divide by two and you’ve got your tire radius!
Measuring the depth of a mounting hex is an important step. To measure this accurately, place some sturdy material like cardboard on your inner side rim and then make note of how far down it reaches into where you will be working.
We now know the width of our box, so we need to subtract it from total.
How to calculate RC car tire offset
Next step is to calculate the offset. You want a negative number if you are going for an aggressive stance, so that means your depth of mounting hex slot should be smaller than the radius of tire.
What is positive offset
A positive offset means the hub mounting surface of the wheel is toward the front of the the centre line of the wheel, so it’s common to find this in newer and FWD vehicles.
What is zero offset
With zero offset, the hub mounting surface of the wheel is in line with the center line of wheel.
What is negative offset
A negative offset means that the wheel mounting surface of the wheel is toward the back of the centre line of the wheel. If a wheel has a deep dish, it usually indicates they have a negative offset.
Conclusion paragraph: In this article, we have discussed everything from the tire’s width to its diameter. We hope that you now feel confident enough to make informed decisions on your next purchase of RC tires for your car or truck.