Tyres for Dummies

Walk into any shoe shop and you will find that there are a bewildering variety of shoes to choose from these days. Shoes for running, shoes for playing sports with, or even shoes for going trekking into the countryside with. Most shoes a fit for purpose and are easily identified by the shape and tread patterns on its sole. 

Like shoes, tyres aren’t identical looking hoops of black rubber, but extensively engineered components that are designed for a specific purpose. There are tyres that optimised to offer the vehicle’s occupants a more comfortable ride, or deliver drivers an improve fuel efficiency. This is why there are so many types of tyres to choose from your local tyre dealer, as each tyre type would affect a car’s handling, performance, comfort, and fuel consumption characteristics.

Performance tyres for example, tend to have large and flat surfaces that allow the tyre to deliver better road holding and cornering grip, which is ideal for high performance and sports cars. Low rolling resistance tyres on the other hand are made to allow the tyre to maintain its rolling momentum when the car is moving and thus improve the car’s fuel efficiency. There are even tyres that have softer side walls to give a more cushioning ride and tread patterns that reduce noise from the road, which are specifically suited for big luxury cars where passenger comfort is key.

SUVs and pick-up trucks have dedicated tyres as these vehicles require tyres that are tough enough to handle its weight, as well as any terrain that would have otherwise punctured the thin structure found on ordinary passenger cars road tyres. For the more adventurous types there are off-road tyres that feature deep grooves and rubber blocks that protrude out of the tyre sides, enabling the tyres to deliver grip to pull itself out of any slippery or muddy situation. While these off-road tyres are ideal for driving through mud and rocky surfaces, such tyres generate a lot of noise and cause passenger discomfort when driven on the road.

Making Sense of Numbers – Understanding Tyre Markings

After picking a tyre that would best suit your vehicle and your demands, the next step is to choose an appropriately sized tyre that would fit the vehicle’s wheels. You might have seen the familiar markings on a tyre’s sidewall, such as 205 60 R15 91H, or a different set of numbers that were printing in the same format. Understanding the meaning behind these codes will help you in picking out the right set of tyres for your vehicle.

The first three sets of numbers are fairly well understood by many and is a very basic knowledge that drivers should know.

The first three numbers (in this example – 205) specifies the width of the tyres in millimetres. It can range from 125 to 335 millimetres. High performance cars have wider tyres fitted on the axles that are driving the car, for better traction.

The second set of numbers (in this example – 60) is the height-to-width ratio, also known as the aspect ratio. This particular tyre has an aspect ratio of 60, so its sidewalls are 60 percent the width of the tyre.

High performance tyres usually have a low aspect ratio number, indicating that it has a very thin sidewall, commonly known as low-profile tyres. Low profile tyres are able to resist sidewall deformation better during hard cornering, but depending on vehicles, it may result in poorer ride comfort.  

The next figure refers to the rim diameter, which is measured in inches. They typically range from 14 to 19. The meaning of the alphabets on the other hand, are less well understood.

Determining the Construction of the Tyre and its Abilities

The letter R indicates that the tyre is uses radial-type construction. All modern tyres on sale today are radial tyres, where textile cords of the casing are arranged at right angles to the tyre’s running direction.

Tyres with an additional F letter behind the R indicates run-flat tyres, a type of puncture resistant tyre commonly used in many high-end European cars, which are able to continue driving at a limited speed (usually not more than 80km/h for a distance of around 200km if the vehicle is carrying only two adults with no loads) even after suffering a puncture.

The alphanumeric code 91 H refers to its speed and load rating. The numbers indicate its load rating – the maximum load the tyres can support when properly inflated.

In this case, the tyre’s load index number of 91 indicates that it can support a maximum load of 615kg. A smaller tyre with a load index of 1 can support up to 46kg.

The letter H refers to its speed rating. H-rated tyres can go up to 210km/h. The highest rating (Y)-rated tyres can go over 300km/h.

Identifying a Tyre’s Origin

There’s also another set of numbers indicating the tyre’s manufacturing plant, brand, tread pattern as well as its month and year of manufacture.

Next is the Department of Transport (DOT). The code 5M RL YB H 1515 indicates that the tyre is manufactured at the Hankook’s Geumsan plant (code 5M), made by Hankook (brand code H) in the fifteenth week of year 2015 (1515).

The remaining codes RL and YB refers to its size and tread pattern code.

Below is the range of Hankook tyres available for Malaysia. 

For more information about Hankook tyres, visit www.hankooktire.com/global/tires-services.html or follow them at their official Facebook page at www.facebook.com/hankooktiremalaysiasdnbhd.

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