Go-Kart Tire and Wheel Sizes: Charts, Markings and Dimension Calculations

A go-kart tire size is usually printed on the sidewall in an inch-based format such as 10x4.50-5. This means a nominal overall diameter of 10 inches, a nominal tire width of 4.50 inches, and a rim diameter of 5 inches. Some kart tires use a two-number format, such as 4.10/3.50-4, which gives width and rim diameter but no overall diameter. Others use a metric format, such as 145/70-6, which gives width in millimetres, an aspect ratio in percent, and rim diameter in inches. From these numbers you can calculate sidewall height, overall tire diameter and tire circumference. The results are nominal geometry, not exact measurements of a mounted tire, and they do not show whether a tire will fit a particular kart.

What the numbers on a go-kart tire sidewall mean

Go-kart tire size markings describe three things: how tall the tire is, how wide it is, and which rim diameter it mounts on. The rim diameter is the one value that must match the wheel exactly. The order of the numbers and the units depend on which of the three common formats the tire uses.

Three-number inch sizes: diameter x width - rim (example 10x4.50-5)

In a three-number inch-based tire size, the first number is the nominal overall tire diameter, the second is the nominal section width, and the number after the dash is the rim diameter. All three are in inches.

• 10 = overall diameter of about 10 in (254 mm)
• 4.50 = tire width of about 4.50 in (114 mm), measured across the widest part of the tire, not the tread
• 5 = fits a 5 in diameter rim

This is the most common format for sprint racing karts, rental karts and many off-road kart tires. Because the overall diameter is stated directly, it is the easiest format for comparing tire heights.

Two-number sizes: width - rim (example 4.10/3.50-4)

A two-number size such as 4.10/3.50-4 gives the section width and the rim diameter, but not the overall diameter. The split figure 4.10/3.50 means the tire is sold under two interchangeable width designations. The 4 after the dash means a 4 in rim. These sizes are common on small utility wheels and some minibikes and yard karts. To learn the overall diameter, check the manufacturer's published specification or measure the mounted, inflated tire.

Metric sizes: width / aspect ratio - rim (example 145/70-6)

A metric kart tire size gives the width in millimetres, then the aspect ratio, then the rim diameter in inches. The aspect ratio is the sidewall height expressed as a percentage of the width.

• 145 = tire width of 145 mm
• 70 = sidewall height is 70% of 145 mm, which is 101.5 mm
• 6 = fits a 6 in rim

Metric sizes do not state overall diameter, so you calculate it. The method is shown in the calculation section below.

Other sidewall markings: construction and performance information

Not every number on a kart tire is a dimension. These markings describe construction, use or performance:

• Ply rating (for example 2PR or 4PR): an index of carcass strength. It is common on off-road and utility kart tires. It does not count the actual layers in modern construction.
• Load rating or maximum load: the maximum weight one tire is rated to carry, often printed with a maximum inflation pressure. This is a limit, not a recommended running pressure.
• Tubeless (TL) or tube type (TT): shows whether the tire seals directly on the rim bead or needs an inner tube.
• Compound or type name: racing kart tires carry a manufacturer code or name that identifies the rubber compound (softer or harder) and whether the tire is a slick or a wet-weather tire. The codes are brand-specific and are not comparable across manufacturers.
• Rotation arrow: directional treads, especially rain tires and off-road tires, must be mounted to roll in the direction of the arrow.
• Use statements such as Not for Highway Use: most kart tires have no road speed rating, because they are not designed or approved for road vehicles.

Go-kart tire size chart: racing and rental karts

The kart tire size chart below lists inch-based sizes commonly seen on sprint racing and rental karts. All of them mount on 5 in or 6 in rims. The sidewall height, aspect ratio and circumference columns are calculated from the nominal size using the formulas later in this article. Real tires measure slightly differently.

Tire size	Nominal diameter	Width	Rim diameter	Calculated sidewall height	Approx. aspect ratio	Calculated circumference
10x4.00-5	10 in (254 mm)	4.00 in	5 in	2.5 in	63%	31.4 in (798 mm)
10x4.50-5	10 in (254 mm)	4.50 in	5 in	2.5 in	56%	31.4 in (798 mm)
11x4.00-5	11 in (279 mm)	4.00 in	5 in	3.0 in	75%	34.6 in (878 mm)
11x6.00-5	11 in (279 mm)	6.00 in	5 in	3.0 in	50%	34.6 in (878 mm)
11x7.10-5	11 in (279 mm)	7.10 in	5 in	3.0 in	42%	34.6 in (878 mm)
13x5.00-6	13 in (330 mm)	5.00 in	6 in	3.5 in	70%	40.8 in (1,037 mm)
13x6.50-6	13 in (330 mm)	6.50 in	6 in	3.5 in	54%	40.8 in (1,037 mm)

Sprint racing karts usually run a staggered setup: narrower, smaller-diameter tires at the front, such as 10x4.50-5, and wider, larger-diameter tires at the rear, such as 11x7.10-5. In organised racing, the exact tire model and size are normally set by class rules. The chart helps you read and compare sizes. It does not show which tire is legal in a given class.

Off-road go kart tire size chart

Off-road kart tires are generally taller and use larger rims than sprint racing tires, most often 6 in or 8 in. This off-road go kart tire size chart covers common yard kart, buggy and off-road kart sizes. The calculated values come from the nominal size.

Tire size	Nominal diameter	Width	Rim diameter	Calculated sidewall height	Approx. aspect ratio	Calculated circumference
4.10/3.50-4	Not stated in size	4.10 or 3.50 in	4 in	Check manufacturer data	Not stated	Measure or check data
145/70-6	14.0 in (355 mm), calculated	145 mm (5.7 in)	6 in	101.5 mm (4.0 in)	70%	44.0 in (1,117 mm)
15x6.00-6	15 in (381 mm)	6.00 in	6 in	4.5 in	75%	47.1 in (1,197 mm)
16x6.50-8	16 in (406 mm)	6.50 in	8 in	4.0 in	62%	50.3 in (1,277 mm)
18x8.50-8	18 in (457 mm)	8.50 in	8 in	5.0 in	59%	56.5 in (1,436 mm)
18x9.50-8	18 in (457 mm)	9.50 in	8 in	5.0 in	53%	56.5 in (1,436 mm)
19x7.00-8	19 in (483 mm)	7.00 in	8 in	5.5 in	79%	59.7 in (1,516 mm)
20x10.00-8	20 in (508 mm)	10.00 in	8 in	6.0 in	60%	62.8 in (1,596 mm)
22x11.00-8	22 in (559 mm)	11.00 in	8 in	7.0 in	64%	69.1 in (1,756 mm)
22x11.00-10	22 in (559 mm)	11.00 in	10 in	6.0 in	55%	69.1 in (1,756 mm)

The last two rows show why rim diameter matters. 22x11.00-8 and 22x11.00-10 have the same nominal overall diameter and width. They need different wheels, though, and the 10 in version has a 1 in shorter sidewall on each side of the rim.

Is there a standard go kart tire size?

There is no single standard go kart tire size that fits all karts. Standard sizes exist within each type of kart:

• Sprint racing karts: 5 in rims, with fronts around 10 in in diameter (for example 10x4.50-5) and rears around 11 in (for example 11x7.10-5 or 11x6.00-5). Wet-weather tires generally use similar diameters with narrower widths.
• Rental and leisure karts: often 5 in or 6 in rims, with sizes such as 11x4.00-5, 13x5.00-6 or 13x6.50-6.
• Yard karts and off-road karts: commonly 6 in or 8 in rims, with diameters roughly between 13 in and 22 in. Front tires are often narrower than rear tires.

Read a manufacturer's "standard size" as the size that kart was designed around, not as a universal value. The tire currently on your kart, or the owner's manual, is the reference point for any comparison.

Go-kart wheel size chart: rim diameter and rim width

A go-kart wheel size is described mainly by rim diameter and rim width. Rim diameter must match the last number of the tire size exactly. Rim width affects how the tire's sidewalls sit and how wide the mounted tire becomes.

Wheel attribute	What it means	Must it match the tire?
Rim diameter (4, 5, 6, 8, 10 in)	Diameter of the bead seat where the tire seals	Yes, exactly. A 5 in tire cannot be mounted on a 6 in rim.
Rim width	Distance between the inner edges of the rim flanges. Off-road wheels are often listed as diameter x width (for example 8x7). Racing rims are usually listed in millimetres.	It must suit the tire's width range. Too narrow or too wide changes the tire's shape and can affect bead seating.
Hub mounting (bolt pattern, centre bore, axle or spindle fit)	How the wheel attaches to the kart	It must match the kart, not the tire.
Offset or backspacing	Where the rim sits relative to the mounting face	It affects track width and clearance, not tire size.

In sprint karting, front rims are typically narrower than rear rims. Rear rims are often around 180 to 215 mm wide to suit wide rear slicks, but the correct width depends on the tire and the class rules. For off-road karts, the tire manufacturer's recommended rim width range is the reference.

How to calculate go-kart tire dimensions

A go kart tire size calculator performs a few simple calculations, and you can do them by hand. The method depends on whether the size gives the overall diameter directly (three-number inch sizes) or as an aspect ratio (metric sizes). Keep units consistent: 1 in = 25.4 mm.

Inch-based three-number sizes

1. Read the overall diameter (D), the width (W) and the rim diameter (R) from the size. For 10x4.50-5: D = 10 in, W = 4.50 in, R = 5 in.
2. Calculate sidewall height: (D − R) ÷ 2. For 10x4.50-5: (10 − 5) ÷ 2 = 2.5 in.
3. Calculate the approximate aspect ratio: sidewall height ÷ W × 100. For 10x4.50-5: 2.5 ÷ 4.50 × 100 ≈ 56%.
4. Calculate circumference: D × π (3.1416). For 10x4.50-5: 10 × 3.1416 ≈ 31.4 in.

Metric sizes

1. Read the width in mm, the aspect ratio in percent and the rim diameter in inches. For 145/70-6: 145 mm, 70%, 6 in.
2. Calculate sidewall height: width × aspect ratio ÷ 100. For 145/70-6: 145 × 0.70 = 101.5 mm.
3. Convert the rim diameter to mm: 6 × 25.4 = 152.4 mm.
4. Calculate overall diameter: rim diameter + 2 × sidewall height. For 145/70-6: 152.4 + 203 = 355.4 mm, which is about 14.0 in.
5. Calculate circumference: 355.4 × 3.1416 ≈ 1,117 mm, which is about 44.0 in.

Revolutions per mile and distance per revolution

Tire circumference is the distance a tire rolls in one revolution. To get revolutions per mile, divide 63,360 (the number of inches in a mile) by the circumference in inches. A 10 in tire with a 31.4 in circumference turns about 2,017 times per mile. An 11 in tire with a 34.6 in circumference turns about 1,834 times per mile. In metric terms, divide 1,000,000 mm by the circumference in mm to get revolutions per kilometre.

How width, aspect ratio and rim diameter change tire size

Each part of a kart tire size affects the dimensions differently. Which values change depends on the format.

Changing overall diameter

In inch-based three-number sizes, a larger first number means a taller tire, a larger circumference and more distance covered per revolution. Moving from a 10 in to an 11 in rear tire increases diameter and circumference by 10%. At the same axle speed, the kart travels about 10% further per revolution. This has the same effect as gearing slightly taller. Axle height rises by half the diameter difference: (11 − 10) ÷ 2 = 0.5 in.

Changing width

In inch-based three-number sizes, width is listed separately from diameter. 18x8.50-8 and 18x9.50-8 therefore have the same nominal height and circumference, and only the width differs by 1 in. In metric sizes, width also changes height, because sidewall height is a percentage of width. Compare 145/70-6 and 165/70-6:

• 145/70-6: sidewall 101.5 mm, overall diameter about 355 mm (14.0 in)
• 165/70-6: sidewall 115.5 mm, overall diameter about 383 mm (15.1 in)

Adding 20 mm of width at the same 70% ratio makes the tire about 28 mm (1.1 in) taller.

Changing aspect ratio

A lower aspect ratio means a shorter sidewall relative to the tire width. At the same width and rim diameter, lowering the aspect ratio reduces overall diameter. The calculated aspect ratios for inch sizes show the difference in proportions. A 10x4.50-5 front (about 56%) has a relatively taller sidewall for its width than an 11x7.10-5 rear (about 42%).

Changing rim diameter

If overall diameter stays the same and rim diameter increases, the sidewall gets shorter. A 22x11.00-8 has a 7 in sidewall, and a 22x11.00-10 has a 6 in sidewall. Rim diameter is never interchangeable. A tire for a different rim diameter needs a different wheel.

Comparing two kart tire sizes step by step

1. Convert both sizes to overall diameter, width and rim diameter in the same unit.
2. Check rim diameter first. If it differs, the tire will not fit the existing wheel.
3. Subtract the diameters, then divide the difference by the original diameter to get the percentage change. That same percentage applies to circumference and distance per revolution.
4. Divide the diameter difference by 2 to estimate the change in axle height and ground clearance.
5. Compare widths, and check whether the new width suits your rim width and the space available on the kart.

Calculated size vs actual tire dimensions

The dimensions printed on a kart tire and the values calculated from them are nominal. A mounted tire on a running kart can measure differently for several reasons:

• Brand and model: two tires labelled 11x7.10-5 from different manufacturers, or with different compounds, can differ in measured diameter and width.
• Rim width: section width is specified on a particular rim width. A wider rim pulls the sidewalls out and usually increases measured width. A narrower rim does the opposite.
• Inflation pressure: kart tires run at low pressures, so small pressure changes noticeably alter the tire's shape and diameter.
• Temperature and speed: tires can grow slightly when hot and at speed.
• Wear: tread wear reduces diameter over time, which matters most when matching rear tires.
• Load: the loaded rolling radius under the kart's weight is smaller than half the unloaded diameter.

For precise work, such as matching rear tire circumferences or calibrating a wheel-speed sensor, measure the mounted, inflated tire. Run a tape around the tread at the centreline to get circumference, or roll the kart one full wheel revolution and measure the distance travelled.

What a tire size does not tell you about fitment

A matching or similar tire size shows that the dimensions are comparable. It does not confirm that the tire will fit or suit a particular kart. Check these points separately:

• Wheel compatibility: rim diameter must match exactly, and rim width must fall within the tire's intended range.
• Clearance: taller or wider tires may contact the frame, bodywork, bumpers, brakes, chain or steering components, especially at full steering lock or under suspension travel on off-road karts.
• Hub and axle fit: bolt pattern, centre bore, axle or spindle size and offset belong to the wheel, not the tire.
• Load and intended use: the tire's load rating and design (racing slick, rain, turf, all-terrain) must suit the kart's weight and surface.
• Rules: in sanctioned karting, the permitted tire is usually specified by brand, model and size. A dimensionally similar tire may still be illegal.

To use any go kart tire size guide or chart effectively, start with the numbers on your current tire's sidewall. Convert them into diameter, width, rim diameter and circumference, then compare the alternative size with those values. Treat the result as a dimensional comparison, and confirm actual fit on the kart.