Graham FisherBy Graham Fisher

Updated November 2026

An ATV tires size chart lets you translate the numbers stamped on a tire into height, width and rim diameter, so you can confirm a set will fit your machine. This guide shows you how to read those numbers, check them against your current tires and rims, and choose a size that suits your riding. Get the measurements right and you avoid rubbing, poor handling and wasted money on the wrong set.

How to Read an ATV Tire Size Code

Most ATV tires use a three-part code, such as 25×8-12. Each part means something specific:

Shopping for one? See our guide: 6 Best ATV Tires by Sizes for Every Trail and Rider (2026).

  • First number (25): overall tire diameter in inches, measured from the top of the tread to the bottom.
  • Second number (8): tire width in inches, measured across the tread at its widest point.
  • Last number (12): rim diameter in inches, the size of wheel the tire mounts to.

Some tires add a letter, such as R for radial construction, or list an alternate metric width. Those letters do not change the core three numbers, so read them as extra information about construction.

Using a Size Chart to Match Your Current Tires

Before you shop, measure or confirm what you already run. Your owner’s manual and the sidewall of the existing tire both list the size. A chart is most useful when you compare like with like:

  1. Note the rim diameter first. This is the one number that cannot change without swapping wheels.
  2. Check overall diameter next. A tire that is noticeably taller or shorter alters ground clearance, speedometer readings and gearing.
  3. Compare width last. A wider tire can rub the frame, fenders or A-arms at full steering lock, so check clearance before you commit.

Stay within about half an inch of stock diameter when you can. Larger changes affect the drivetrain and may require re-jetting or other adjustments, so treat them as a bigger project.

Factors Beyond the Size Code

Two sets of tires with identical numbers can ride very differently. Consider these points alongside the chart:

  • Tread pattern: aggressive lugs suit mud and loose terrain, while smoother patterns suit hardpack and mixed trail riding.
  • Ply rating: a higher ply rating generally signals a stiffer, more puncture-resistant sidewall, which matters for rocky trails.
  • Construction: radial tires tend to flex differently than bias-ply tires, so check what your rims and riding style favor.
  • Load and use: utility riders carrying gear or towing need a tire rated for that load.

Checklist Before You Order

  1. Confirm the rim diameter on your current wheel or the owner’s manual.
  2. Write down the existing overall diameter and width.
  3. Decide whether you want a size change or a like-for-like replacement.
  4. Check fender and frame clearance for any width increase.
  5. Set the correct tire pressure once mounted, following the manufacturer’s specification.

Common Mistakes to Avoid

  • Assuming all sizes with the same rim diameter will interchange. Width and height still matter.
  • Ignoring the speedometer. Larger tires can make it read low.
  • Skipping the clearance check on a wider set, which often shows up as rubbing on the first hard turn.
  • Mixing sizes front and rear without confirming the machine allows it.
  • Reading a chart from a different brand as exact. Sizing varies slightly between manufacturers, so verify the actual tire.

A tire pressure gauge helps you set pressures accurately after mounting, which affects grip and rim protection. A tread depth gauge makes it easier to judge when a set is worn enough to replace.

FAQ

Can I change my ATV to a different tire size?

Often yet, but only within limits. Keep rim diameter the same unless you change wheels, and check clearance and speedometer accuracy before riding. Consult your dealer or owner’s manual for your model’s guidance.

Does a bigger tire mean a faster ATV?

Not necessarily. Larger tires raise effective gearing, which can reduce acceleration and strain the drivetrain. Results depend on your machine and setup.

Where do I find the size on my current tires?

The size code is molded into the sidewall, usually near the bead. Your owner’s manual also lists the factory specification.

Conclusion

An ATV tires size chart is most useful when you read the three numbers correctly and compare them to your current setup. Start with rim diameter, check overall height and width, and confirm clearance before buying. Once you have the right size, the tread and construction you choose will shape how the tires perform on your trails.

Ready to choose one?

Graham Fisher

About Graham Fisher

Graham Fisher is part of our editorial team and reviews and edits our ATV, UTV/side-by-side & dirt bikes guides, checking product details against manufacturer specifications and owner feedback.