ATV and UTV Tire Sizes: How to Read Them and What Fits
Quad and side-by-side tires use a simple three-number size that gives height, width and rim size in inches. Here is how to read it, the sizes each class of machine uses, and how far you can go up in size.
An ATV tire size like 25x8-12 means the tire is 25 in (635 mm) tall, 8 in (203 mm) wide, and fits a 12-inch rim. A dash means bias-ply; an R (25x8R12) means radial. Utility ATVs usually run narrower fronts than rears, such as 25x8-12 front and 25x10-12 rear.
- Height
- 25 in (635 mm)
- Width
- 8 in (203 mm)
- Rim diameter
- 12 in
- Typical pressure
- 4-7 psi
On this page
How to read an ATV tire size
ATV and UTV tires state their size directly in inches, in the order height × width - rim. No calculation is needed.
| Marking | Meaning |
|---|---|
| AT | All-terrain (ATV) tire. Optional prefix; it does not change the size. |
| 25 | Overall height (diameter) when inflated: 25 in (635 mm) |
| 10 | Section width: 10 in (254 mm) |
| R or - | R = radial; a dash = bias-ply |
| 12 | Rim diameter: 12 in |
| 6PR | Ply rating: strength equivalent to 6 plies |
| NHS | Not for Highway Service. Not legal or safe for road use. |
Nominal sizes are rounded. A tire sold as 26 in may measure 25.3-26 in when mounted and inflated to off-road pressures, and the gap between brands can reach about 1 in. If clearance is tight, look up the measured height in the maker's spec table.
Metric ATV sizes
Some radial ATV tires use car-style metric sizes. Convert them the same way as a car tire: width × aspect ratio × 2, plus the rim.
| Metric size | Calculated height | Width | Nearest inch size |
|---|---|---|---|
| 205/80R12 | 24.9 in (633 mm) | 8.1 in | 25x8-12 |
| 255/65R12 | 25.1 in (636 mm) | 10.0 in | 25x10-12 |
| 205/80R14 | 26.9 in (684 mm) | 8.1 in | 27x8-14 |
| 255/70R14 | 28.1 in (713 mm) | 10.0 in | 28x10-14 |
ATV tire size chart by machine type
Factory sizes by class. Utility and sport quads use a narrower front tire; side-by-sides often use the same size all round or a slightly wider rear.
| Machine | Front | Rear | Rim size |
|---|---|---|---|
| Youth ATV (50-110 cc) | 16x8-7, 18x7-8 | 16x8-7, 18x9.5-8 | 7-8 in |
| Sport ATV (250-700 cc) | 21x7-10, 22x7-10 | 20x10-9, 20x11-9 | Front 10 in, rear 9 in |
| Small utility (250-500 cc) | 24x8-11, 24x8-12 | 24x10-11, 24x10-12 | 11-12 in |
| Mid utility (500-700 cc) | 25x8-12 | 25x10-12 | 12 in |
| Large utility (700-1000 cc) | 26x8-12, 26x8-14 | 26x10-12, 26x10-14 | 12-14 in |
| Utility side-by-side | 25x8-12 to 27x9-14 | 25x10-12 to 27x11-14 | 12-14 in |
| Sport side-by-side | 28x10-14 to 32x10-15 | 28x10-14 to 32x10-15 | 14-15 in |
The sport ATV pattern (tall narrow front on a 10-inch rim, short wide rear on a 9-inch rim) puts more rubber on the ground at the drive wheels and keeps the steering light. Utility quads use equal heights front and rear because both axles are driven in four-wheel drive.
Front and rear: why widths differ
- Narrower front (8 in): lighter steering, especially on machines without power steering, and less push in tight turns.
- Wider rear (10-11 in): more traction and flotation where the weight and drive sit.
- Same height front and rear: on 4x4 machines this keeps both axles turning at the same speed. Mismatched heights strain the front differential. Replace front and rear tires as matched sets, and do not mix brands with different measured heights on a 4x4.
Going up a tire size
Taller tires add ground clearance (half the diameter increase) but reduce effective gearing.
| New height | Ground clearance gain | Gearing change | Usual requirement |
|---|---|---|---|
| 26 in | +0.5 in (13 mm) | 4% taller | Bolt-on on most machines |
| 27 in | +1 in (25 mm) | 8% taller | Check A-arm and fender clearance at full lock |
| 28 in | +1.5 in (38 mm) | 12% taller | Often a lift kit; clutch spring changes on CVT models |
| 30 in | +2.5 in (64 mm) | 20% taller | Lift kit and clutch kit; heavier axles advised |
A 20% taller tire makes the speedometer read 20% low and puts more load on the CVT belt in low-speed work, which shortens belt life. Taller, heavier tires also raise the center of gravity, which matters on side hills.
Tires marked NHS are built for low speeds and low pressures off-road. Running them on pavement wears them fast and makes handling unpredictable. Use DOT-rated tires if your UTV is street-legal where you live.
ATV tire pressure
ATV tires run at very low pressure, measured cold with a low-pressure gauge (0-15 psi). A standard car gauge is not accurate at these values.
- Utility and sport ATVs: typically 4-7 psi (28-48 kPa). The figure is on the vehicle's label or in the manual; some machines specify different front and rear pressures.
- Side-by-sides: typically 10-20 psi (69-138 kPa), higher in the rear when loaded.
- Equal pressure side to side: a 1 psi difference is a large percentage at these pressures and makes the machine pull.
ATV wheels and bolt patterns
Rims are sized width × diameter (12x7 is 12 in diameter, 7 in wide) with an offset written as two numbers, such as 4+3: 4 in of backspacing and 3 in outward. Tires usually sit on rims 1-2 in narrower than the tire's nominal width: an 8 in tire on a 6-7 in rim and a 10 in tire on an 8-9 in rim.
| Bolt pattern | Brands (most models) |
|---|---|
| 4/110 | Honda, Yamaha, Suzuki, many Kawasaki ATVs |
| 4/115 | Most later Arctic Cat (Textron) ATVs |
| 4/137 | Can-Am |
| 4/156 | Polaris (2005 and later) |
Patterns vary by model and year, so confirm with the manual or measure across two opposite studs. The wheel size guide explains offset and measuring in more detail.
For road-going motorcycles and dirt bikes, see the motorcycle tire size guide. If you tow your quad, the trailer's own tires are covered in the trailer tire guide, and the size system used on cars and trucks is explained in the tire size chart.
Frequently asked questions
What does AT mean on an ATV tire size?
AT stands for all-terrain and simply marks the tire as an ATV tire, as in AT25x8-12. It does not change the dimensions: AT25x8-12 and 25x8-12 are the same size.
Is a 25x10-12 tire taller than a 25x8-12?
No, both are nominally 25 in tall. The 25x10-12 is 2 in wider and needs a wider rim, which is why it is used on the rear of many utility ATVs while the 25x8-12 goes on the front.
What is the metric equivalent of a 25x8-12 ATV tire?
A 205/80R12 is the closest metric size: 205 mm (8.1 in) wide with a calculated diameter of 24.9 in. A 25x10-12 is close to 255/65R12 (25.1 in).
How much bigger can I go on ATV tires?
Most stock ATVs accept tires 1 in taller than stock without changes. Going 2 in or more often needs a lift kit or clutch work, and raises fuel use and belt wear on CVT machines. Check fender, A-arm and steering-lock clearance before buying.
What ply rating do ATV tires need?
Recreational and utility ATV tires are commonly 2 to 6 ply rated. Six-ply and eight-ply ratings resist punctures from rocks and sticks better and suit side-by-sides, which carry more weight per tire.