Switching your tires has got to be one of the worst things about owning an ATV. Nothing puts a damper on your day like having to replace a tire, whether you’re planning a ride through your local countryside or using your quad for work.
You’re going to have to replace your tires at some point, whether it’s through damage and wear or to switch up your grip for different weather conditions, and when that happens, you’re going to need to make sure you get the right size replacements.
Knowing how to read ATV tire sizes is essential to being able to maintain your machine properly. You really don’t want to order in some new rubber only to find that you’ve got the wrong size, keeping you out of action even longer than necessary.
On the plus side, all tires have size information written on them, but it’s not always presented the same way on the tires. When you’re shopping for new tires, it might be written differently, too. You need to know what that size info means so you can make sure you’re getting the right overall height, width, and rim size for your wheels.
Once you’ve read this guide to how to read your tire size, you won’t have to worry about this problem. We’re going to bust down the way it is written on your tire sidewall, what these codes and numbers mean, and how to make sure you’re always getting the right rubber for your ATV. Let’s get stuck into it so you can get back out there.
Contents
Standard Or Metric
Your first hurdle is figuring out whether your ATV tires list their size in standard or metric measurements. This isn’t too tricky. Let’s look at standard first, as it’s way more common for ATVs than metric measurements. You’ll find these tire size codes on the tire sidewalls.
Standard ATV Tire Measurements
Standard tires have a measurement code made up of three numbers generally separated by dashes or crosses. It’ll look something like 25×8-12 or 25x8x12. These three numbers represent measurements that give you the essential information you need to determine your tire size.
How To Read Standard Measurements?
The first number is the tire diameter, which is expressed in inches, otherwise known as tire height. This is the diameter when properly fitted and inflated to the recommended tire pressure. The second number is the overall tire width when you look at it head-on. Again, this is when it’s mounted to the wheel and properly inflated. The third number is the wheel diameter. This is the measurement of the hole in the center of the tire that corresponds to the rim of the wheel, which tells you what size wheel your tire is suitable for.
Metric ATV Tire Measurements
Metric tire codes look different from the standard measurement codes. They have three two numbers, a letter, and another number. You won’t see these as frequently as the standard measurements because they’re becoming less and less common, but they are still around, so it’s worth knowing how to decode them. Let’s take a look at the sidewall code 205/80R12.
How To Read Metric Measurements?
The first number in the code indicates the width of the tire in millimeters. This is the width as seen head-on. Our tire, in this instance, is 205mm wide. The second number in the code tells you the sidewall height, which is measured from the inner edge of the tire to its outer edge. This is represented as a percentage of the tire’s width as expressed by the first number, which in our example is 80 percent. That works out as a sidewall height of 164mm.
The letter in the code details how the tire is constructed. In our example, the R stands for radial. This means that the belts in the tire radiate out from the center of the wheel across the width of the tire. Radials are the most common form of tires available nowadays, so the strong likelihood is that you will mainly see R in your tire codes.
The other two letters you may come across are B and D, which both indicate diagonally belted tires. These are much less common than radials because their construction leads to tread wear that’s less evenly distributed and faster than radials.
The third number in the metric tire sizing code indicates the wheel diameter. Despite this being the metric sizing system, the wheel diameter is given in inches! It’s not hard to understand why this system is being phased out, given that the standard system is far simpler.
Putting Rubber On The Road
Now you have an understanding of how tire codes are read; you need to know how to put that information into practice, so you know you’re making the right choices for your needs.
Choosing Tire Width
To a large extent, tire width is a case of personal preference. Going wider gives you more grip due to more tread being in contact with the ground, but you sacrifice some of the control you get from narrower tires.
Generally, the rear tires on a quad are narrower than the front ones. Typically, your front pair will be between seven and eight inches wide, while your average rear wheel will be looking for more like 10 to 11 inches.
However, as well as personal preference, you need to ensure that the tires you’re selecting will actually work with the wheels on your ATV. Thankfully, manufacturers include guidelines for their wheels so you can see what the widest and narrowest compatible options would be.
If you don’t have your manufacturer’s spec to hand, you can use a rough-ready reckoner that seems to work in most situations. The widest tire you should fit to a wheel is one that’s two inches wider than the wheel itself. As we said, that’s not a hard and fast rule, but it generally works out.
Choosing Tire Diameter
Your tire diameter will be determined by some factors outside your control, but you still have a bit of choice in the matter. There’s only so big a tire can get before it interferes with the mudguards, fenders, and wheel wells of your ATV. It’s a bad idea to go for extremes on tire sizes!
Generally speaking, sport quads have the smallest, ranging from 20 to 25 inches. Utility quads are a little bigger, from around 24 to 28 inches, and mud or rock quads fall in a range between 27 and 30 inches. If you stick within these ranges, you’ll be good to go. You can always check your manufacturer’s guidance if you’re looking for further confirmation.
Choosing Wheel Diameter
Well, in this case, there is no choice! Your rim diameter is determined entirely by the size of the wheel on your quad. This is one area where you can’t make any decisions and, happily, you don’t have to because tire manufacturers make their products to fit the vehicles they’re going to be supplying!
What Do You Need?
This very much depends on what you’re going to be doing with your ATV. Are you going off-road, where you’re going to encounter big ruts, rocks, and all manner of obstacles? You’re probably going to be looking for bigger tires than stock, by which we mean ones with a larger overall diameter. These help you to get over lumps and bumps without getting stuck.
If you’re looking for speed over trails or dunes, you want to mount wider tires for more traction than your stock set. Because the surface is smooth, you don’t need to go so big. Rather, you want to prioritize getting as much tread in contact with the surface as possible.
If you’re using your ATV as a general workhorse, you might find your best bet is to stick as close to the OEM stock tires as possible. They’re shipped with what should be the most logical all-around choice for the design of your ATV model, so they’ll give you the best performance in most conditions.
How to Read ATV Tire Size Round-Up
Hopefully, this has cleared up any lingering doubts you may have about how to read the tire size of your ATV tires and what it might mean for you in terms of choosing new rubber. Get out there and enjoy your ATV!
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