Tyre numbers explained

What is the tyre size of a tyre? There are many different variations, but in the UK,. Tyre Width And Aspect Ratio. Using the above example ,. In the example above, the.

Essentially this is the height of the. The R in the tyre marking. Found on the tyre sidewall, these letters and numbers refer to the width , height , diameter , load and speed parameters of your tyres. Understanding these markings will not just improve your car knowledge, but will also help you make the right decision when your old tyres need replacing. Read our guide from etyres.

Aspect Ratio: This is the height of the tyre’s sidewall expressed as a percentage of the tyre’s section width. In addition to the C designation, these sizes are also branded with a load range and service description rating (load range B, C, or D).

Width 2indicates the section width of a tyre in millimetres. Therefore, this radial tyre has a width of 205mm. This refers to the tyre being a radial type- this is like the majority of the tyres used today. Your tyre size can be found on the sidewall of your current tyre and is a sequence of numbers and letters. 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 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.

These numbers let you know what your tyre is capable of. On the sidewall of a tyre you will find various codes and markings. How to read tyre specifications Sidewall Markings.

Amongst these you will find the size. When buying new tyres , make sure you match their speed rating with the speed capabilitie. As VeloNews bike tech expert Lennard Zinn points out, some tyres contain a second series of numbers reflecting the ISO or International Organization for Standardization system.

On a 7X 2 tyre , the. 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. But the height of the tyre usually corresponds quite closely to tyre section, so overall diameter approximately equals the bead diameter plus twice the section. A tyre speed rating indicates the maximum speed a tyre is legally approved for.

This indicates the width of the tyre in millimetres from sidewall to sidewall. These digits express the height of the tyre sidewall expressed as a percentage of the tyre width. So in our example the height is of the tyre ’s width - of 195mm is 126. 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.

So, if a tyre has an aspect ratio of 4 that means the tyre ’s height is of its width. Uses numbers from 1to about 700. Theoretically, a tyre rated 1would have a percent longer lifespan than a tyre rated 1if used in the same conditions — driver, vehicle and roads.

Soft summer tyres tend to have lower treadwear ratings than all-season tyres. This system of markings indicates the tyre size, tyre speed rating, model, and load index. Both low-profile and regular tyres use this marking system as standar so it’s important that you know how to read and understand tyre markings. Tire numbers after the word TREADWEAR estimate how much longer the given tire will last in comparison to the reference tire.

So, if a tire has a rating of 30 it may last times longer than the reference. It is an external noise rating: one black bar means the tyre is 3db or more below future EU legislation. In our example if instead of 6 the aspect ratio was 5 then the tyre would still be 205mm wide, but the height will only be or 102. So an aspect ratio of for example means that the profile height of the tyre is of its width. When it comes to how to read tyre size, the first five digits of the code are the ones to concentrate on.

Note that Light truck tires have two load indexes, unlike passenger tires, because LT tires are mostly used on vehicles with dual rear wheels. So, in the above example, a tyre that has an aspect ratio of would have a height equal to per cent of its width. Slash character for character separation. This tyre will fit over a rim that is inches. Road Bicycle Tire Sizes.

From a practical standpoint, the technical side of tyre sizing might mean little to you,.