What do tyre numbers mean

The two digits following the first slash are what is known as the aspect ratio. What is tyre size code? Essentially this is the height of the tyre as a percentage of the width. So, in the example, the tyre has an aspect ratio of 5 meaning the profile height is of its total width (105mm ). It’s no secret that tyres play an important role in making your car go.

But did you know that the ID number on the side of your rubber is more than just a complicated maths sum?

Watch this video to find out exactly what it all means. LOAD AND SPEED RATING INDEX. This is represented by a series of letters and numbers which starts with the letters DOT (meaning the tyre exceeds Department of Transport safety standards ). The first characters that follow DOT are essentially a serial number used by the manufacturer to identify the tyre and in which production facility it was made. This describes the lenses you need to correct your vision.

Sph is a measure of how powerful the lens is. You can only fit 700c tyres onto your wheel. Wider will increase drag but give you a bit more of a comfy ride.

French designation, the c mean modern clincher. Then there is the less accurate INCH designation × 1⅝ × 1½. Why does one have a width and the other 40?

The letters, numbers, words and symbols written on the sidewall of your tyre are the tyre markings. Not only can this indicate brand and range of the tyre, it also shows you the size of your tyre. The letter tells us what type of vehicle or service the tire was designed for.

In some instances, a tyre number sequence will start with the letter “P”. This stands for “P-metric” or “passenger. This is the most common type of tyre and is designed to be used on passenger vehicles. LT stands for light truck and is designed for SUVs, vans, and the like. When we use tire type “P” or P-Metric, it means that the tire is made according to certain standards of the United States (drafted by TRA) for passenger vehicles.

If there are no letters at the beginning, it refers to the Euro-metric (drafted by ETRTO). The P-metric and Euro-metric differ in load capacities. Following the slash, the next number in the sequence is “ 45”.

This number is the tyre’s aspect ratio – essentially the height of the tyre’s profile outward from the rim represented as a percentage of the tyre’s width. We calculate this number by dividing the tyre’s section height by the tyre’s section width. The first two letters of your car number plate represent where it was registered.

The first letter is for the region and second for the local DVLA office i. Yorkshire and York. By the end of this article, you will fully understand what the numbers and letters on the side of your tyre mean , which parts relate to the tyre size, composition dimensions and capabilities. R tells you the tyre is of radial construction, which is the expected construction for all modern tyres. Tire sizes will often start with letters.

For example P, LT, T, and ST. The number is the tyre load index and indicates the maximum weight the tyre can safely carry when it is fully inflated. Speed Rating The letter at the end of the code is the tyre speed rating. The first three numbers , in this case 19 refer to the section width of the tyre. The aspect ratio, or profile, refers to the height of the sidewall as a of the section width.

The numbers in the tire size refers to different parts of the tire. The first number (205) identifies the section width, or the cross section, in millimeters. Typically following the section width is the sidewall aspect ratio or profile (55). The sidewall height, from rim to tread. The two-digit number after the slash mark in a tire size is the aspect ratio.

Nowadays, bicycle tire sizes are all marked according to ETRTO (European Tire andRim Technical Organization – or ISO) European standard. However, older English and French tire size dimensions are still used as well. Although, the initial two-digit number is the tyre section and roughly indicates the tyre width.

Its actual width is normally less, but varies according to how the tyre is designed and the width of rim to which it is fitted. The R in the tyre marking indicates that this is a radial tyre. This refers to the way the tyre is made.

Put simply, a radial tyre is constructed in a way which means there is less heat buildup. As a result, it provides a more comfortable drive. Automobile tires are described by an alphanumeric tire code or tyre code, which is generally molded into the sidewall of the tire.

This code specifies the dimensions of the tire , and some of its key limitations , such as load-bearing ability , and maximum speed. Sometimes the inner sidewall contains information not included on the outer sidewall, and vice versa. The tire diameter is given for High Flotation tires and omitted from Numeric tires.

The diameter of the tire in inches. Separator character. If the tire diameter is not given, section widths ending in zero (e.g., or 10) indicate the aspect. Tire numbers and letters on a sidewall contain information about the tire’s size, maximum speed and loa age, treadwear capacity, and much more. How to read your tyre size.

Aspect ratio or profile. R means that the tyre has radial ply. The number portion of the characters in brackets represent the load index of the tyre , which specifies the maximum load the tyre can carry.

To find what weight this number corresponds to you will need to refer to a load index table. As you can see, the number means the tyre can carry a load up to 365kg. Manufacturers print a series of numbers on most bicycle tyres.

At a minimum you will see two numbers situated as follows: 7X or X 2. In the first example, your tyre is 700mm in diameter and 23mm wide. The second number reveals tyre width.