QA

How To Read Tire Size Codes

What do tire numbers and letters mean?

Also known as the service description, the number indicates the maximum load the tire can support when inflated properly, and the letter represents the maximum speed capability of the tire. In our example, a load index of 92 means that the tire can support 1,389 pounds at maximum air pressure.

What do the 3 numbers mean on tire size?

Tire Width Is the width of the tire measured in millimeters from sidewall to sidewall. The first three-digit number in the tire size refers to the tire width. For instance, in a size P215/65 R15 tire, the width is 215 millimeters.

What does 50r mean on tires?

50 is the two-figure aspect ratio. This percentage compares the tire’s section height with the tire’s section width. For example, this aspect ratio of 50 means that the tire’s section height is 50% of the tire’s section width. R indicates the construction used within the tires casing. R stands for radial construction.

What does 255 mean on tires?

255 (Tire Width): The tire width is 255 millimeters from sidewall to sidewall (just over ten inches). 45 (Aspect Ratio): The tire’s sidewall is 45% of the tire’s width, which means the sidewall is about 114 millimeters or just over 4 inches.

What do the symbols on a tire mean?

There are two common grading systems for tires to help identify winter tire traction capabilities. All tires that pass certain winter tire traction tests can be marked with a symbol molded onto the side of the tire. One is the M+S (mud and snow) symbol, and the second is the mountain/snowflake symbol.

What do the codes on a tire mean?

The two-digit number that usually follows the tire’s section width tells us the aspect ratio, or tire profile measurement. A lower aspect ratio means a lower-profile tire with a shorter sidewall, while a tire with a higher aspect ratio will have a taller sidewall and look more like a donut.

What is the difference between a 60 and 65 series tire?

The 65% aspect ratio (as in 235/65/17), compared to 60%, adds almost 12 mm (1/2″) to the radius of the tire (0.65-0.60)*(235mm)=11.75mm.

Can I use 245 tires instead of 235?

So you have already identified the difference between 235 and 245 size tires. It is obvious that 245 is bigger than 235, still, both tires’ sizes are pretty common and could be interchangeable at times.

Will a 65 tire fit a 60?

Yes, the only real difference is that ratio between the tread width and the height of the sidewall will change. The lower the middle number the lower the profile of the tire the larger the number the higher the tire profile.

What does 98 mean on a tire?

The 98 says the tire can safely carry — when properly inflated — 1,653 pounds. This code ranges from 60 (551 pounds) to 114 (2,601 pounds). The speed rating (sometimes listed twice — in front of the R and always here) ranges from M (81 mph) to Z (149+ mph).

What does 99 mean on a tire?

The higher the tire’s load index number, the greater its load carrying capacity. 97 = 1,609 pounds. 98 = 1,653 pounds. 99 = 1,709 pounds. A tire with a higher load index than that of the Original Equipment tire indicates an increase in load capacity.

What does r20 mean on a tire?

Bias Belt. D. Diagonal. 20. The tire size was designed to fit rims or wheels that are 20 inches in diameter.

Are 255 tires wider than 245?

While the exact dimensions of a 245 or a 255 tire can vary somewhat between tire manufacturers, for any specific manufacturer a 255 tire will have a wider section width (bulge or tread width) than a 245 tire, the difference being 10 mm.

What is the difference between a 265 tire and a 255 tire?

The tread section width of the 265 tire is 10mm wider than the 255 tire. Simple math. A radial tyre has three numbers on it eg. 255/45 X 16 equals 255 mm width and the distance between the wheel and circumference is 45% of the width and the circumference of the wheel is 16 inches.

Which tire is taller 275 or 285?

The 275 tire is about 0.55 inches or 15 mm smaller than the 285 tire and their speedometer difference is also about 1.7 percent too. With regards to sidewall height, the 275 is slightly taller than 285 but revolves just a shade slower than the 285 tire.

What does XL mean on a tire?

XL tyres have been especially developed for use with heavy loads. Generally speaking, the tyre name XL is used for heavy duty tyres. However, the labelling varies between tyre manufacturers. Sometimes you might have XL tyres that are also labelled “reinforced” (RF or RFD), or models labelled EL (Extra Load).

What does the 40 mean on a tire?

In this case, the tire is 245 millimeters at its widest point (when it’s mounted on a wheel of a specified width). 2) The number after the slash indicates its aspect ratio, or profile. This tire’s sidewall height is 40 percent of its width.

What does the T or H mean on tires?

The “T” or “H” on tires pertain to their speed ratings. A T-rated tire can withstand top speeds of up to 118 mph (190 km/h), while an H-rated tire can support up to 130 mph (210 km/h). It is important to note these markings and stay within those speed limits.