Three numbers, sometimes a letter, and they decide whether your quad clears the next rut or rubs a fender. Here is how to read every part of the code before you buy.
You're standing in front of a tire, or a whole rack of them, and the sidewall reads 27x11-14. Three numbers. Sometimes a letter shoved in the middle. Somehow that little code decides whether your machine clears the next rut or rubs a fender every time you land off a bump.
It's not complicated once you know what each part is doing. Read the sidewall on the tires you already run, line it up against what's in our ATV and UTV tires and rims selection, and you can shop the next set without guessing. Here's what every number and letter is actually telling you, and what changes on the trail when you start moving them around.
Start With the Three Numbers
Most ATV and UTV tires use the imperial format, and it's the easy one. Three measurements, all in inches. Take a common size like 27x11-14:
- 27 is the overall height, or diameter, of the tire: ground to top, inflated.
- 11 is the width across the tread.
- 14 is the rim diameter the tire mounts on.
That's the whole code. A 27x11-14 is 27 inches tall, 11 inches wide, on a 14 inch wheel. You'll see the same size written a few ways, like 27x11x14 or 27-11-14. Same tire. The separators don't change the measurements.
The last number is the one you can't fudge. A tire built for a 14 inch rim does not go on a 12 inch rim. They look close on a shelf. They are not interchangeable, and forcing it is how a tire lets go of a wheel at the worst possible moment. Match the rim diameter exactly, every time.
That Letter in the Middle: Radial or Bias
Sometimes the size reads 27x11R14 instead of 27x11-14. That R is not a typo. It's telling you how the tire is built.
An R between the width and the rim number means the tire is radial. No letter, just a dash or an x, means it's bias ply. One character, two very different tires, which brings us to the part that actually changes how the machine feels.
Bias or Radial: Match It to How You Ride
Both hold air and go round. How the cords inside are laid out is where they split.
Bias ply tires run their cords diagonally, crisscrossing from bead to bead. That builds a stiffer sidewall and a tougher carcass. They shrug off punctures better, which is why rock and mud riders keep reaching for them, and they cost less. The trade is a rounder profile, a smaller contact patch, and a rougher ride.
Radial tires run their cords straight across, bead to bead, usually with a belt under the tread. The sidewall flexes more, the contact patch sits flatter and wider, and the tire tracks better at speed and wears longer. The ride is smoother, especially over stutter bumps. The give-back is a sidewall that's generally less bombproof than a bias wall in hard rock work.
| Bias ply | Radial | |
|---|---|---|
| Sidewall | Stiffer, tougher | More flex, smoother |
| Ride | Rougher | Smoother, better at speed |
| Puncture resistance | Better | Good, varies by model |
| Tread life | Shorter | Longer |
| Cost | Lower | Higher |
| Best for | Rocks, mud, rough abuse | Trail miles, comfort, speed |
Neither one wins on paper. It comes down to where you actually ride, and you'll find both constructions across our ATV and UTV tire range.
Ply Rating Isn't a Ply Count Anymore
You'll see tires called 2-ply, 4-ply, or 6-ply. Once, that was literal: a 6-ply tire had six fabric layers stacked in it. Not anymore. Modern materials hit the same strength with fewer layers, so ply rating is now shorthand for how tough the tire is and how much load it can carry, not a headcount of layers.
Most ATV tires land between 2-ply and 6-ply. Higher number, tougher casing and more puncture resistance, at the cost of extra weight and a stiffer ride. If you're loading a rack, towing, or riding where sharp rock and cut stumps live, more plies earn their keep. If you want the plushest ride on a groomed trail, you don't need the heaviest casing on the shelf.
The Metric Version You'll Probably Never See
Now and then, usually on an imported machine or a trailer tire, a size shows up looking like 205/80R12. The slash is the tell. Metric is rare on ATVs, but here's how it reads:
- 205 is the width in millimetres.
- 80 is the aspect ratio: the sidewall height as a percentage of the width. So 80% of 205 mm works out to about 164 mm of sidewall.
- R is radial.
- 12 is the rim diameter, back in inches.
The quirk is that metric ATV sizing mixes millimetres and inches in the same code. Width and sidewall in millimetres, rim in inches. Odds are you'll spend your whole riding life in the imperial format, but now the metric one won't throw you if it turns up.
Front, Rear, and Where to Find Your Size
Two things trip people up here.
First, front and rear tires aren't always the same width. On a lot of machines the rears run wider than the fronts, often by around two inches, to put more grip where the power goes down. So a quad might wear 25x8-12 up front and 25x10-12 out back. Check both ends before you order.
Second, you don't have to guess your size. It's stamped right on the sidewall of the tires you're running now, and it's in your owner's manual. Matching your machine's OEM size is the guaranteed-fit move, every time. When you're ready to browse, our ATV and UTV tire and rim listings show the full size and construction up front.
What's Normal for Your Type of Machine
Rough ballparks, because "big" means different things on different machines:
- Sport quads usually run smaller, around 20 to 25 inches in diameter, for quick, responsive handling.
- Utility ATVs sit in the 24 to 28 inch range, the do-it-all middle where most riders live.
- UTVs and side-by-sides go bigger, commonly on 14 inch and larger rims with taller tires to match the weight and the work.
These are starting points, not rules. Whatever you ride, our ATV and UTV hub lines up the tires and rims to match. Your machine's manual and your fenders have the final say.
Going Bigger Without Breaking Something
Bigger tires are the most common upgrade, and the most common way to create new problems.
More diameter means more ground clearance. Roughly, every two inches of added tire diameter buys you about an inch of clearance at the axle. That's real height over rocks, logs, and ruts.
But taller, heavier tires also make the machine work harder. They change your effective gearing, sap low-end power, and throw your speedometer off. Go too big and they rub: fenders, footwells, A-arms, depending on the machine. Stock sizes are often already near the biggest a machine will take without rubbing, so jumping several inches usually means trimming, a lift, or a clutch and gearing change to get the power back.
None of that means don't do it. It means know the cost before you commit, and move in steps, not leaps. Bigger tires lean on the driveline too, so if you're going up, it's worth eyeing the rest of your ATV and UTV parts at the same time.
Match Your Size, Then Shop
Every tire in our ATV and UTV tires and rims selection lists the full size and construction right on the product page, so you can match your machine without the guesswork.
Heading into a Newfoundland winter, a set of ATV and UTV tire chains is worth a look once your size is sorted, and if you're building out a full winter plow rig, the tires you push on matter as much as the blade up front. Not sure your rubber will last the season? Our fall maintenance checklist covers when to replace it.
Frequently Asked Questions
What do the numbers on an ATV tire mean?
In the standard format, like 27x11-14, the three numbers are all in inches: overall height, then tread width, then rim diameter. So a 27x11-14 is 27 inches tall, 11 inches wide, and mounts on a 14 inch rim.
What does the R in an ATV tire size mean?
An R between the width and rim numbers, like 27x11R14, means the tire is radial. No letter, just a dash or an x, means it's bias ply.
Should I run bias or radial tires on my ATV?
Bias ply for rocks, mud, and rough abuse, where the stiffer sidewall resists punctures and costs less. Radial for trail miles and comfort, where the flexible sidewall rides smoother, tracks better at speed, and wears longer. It comes down to where you actually ride.
What does ply rating mean on ATV tires?
It used to be the literal number of fabric layers. Today it's an indicator of the tire's overall strength and load capacity, not a layer count. Most ATV tires run between 2-ply and 6-ply, with higher numbers meaning a tougher, heavier casing.
Can I put bigger tires on my ATV or UTV?
Within limits. Every two inches of added diameter gives you roughly an inch more clearance, but bigger, heavier tires change your gearing, cut low-end power, and can rub the fenders or footwells. Stay within a size or two of stock unless you're ready to trim, lift, or re-gear. If you're not sure how far you can go, ask our gear experts before you buy.
Read the sidewall on what you're running now: height, width, rim, and whether there's an R in there. Match the rim diameter exactly, pick bias or radial by the terrain you actually ride, and if you go bigger, move a size or two at a time instead of all at once. Get those right and the rest is just tread and budget.
