TYRE SIDEWALL INFORMATION AND TREAD DEPTH

Interpreting and understanding the detailed information on the sidewall of your vehicle’s tyres is important in helping you identify the right tyre and operating parameters for your car – an important consideration to achieve the best balance of tyre performance for acceleration, braking and cornering, as well as ride comfort, noise, rolling resistance, mileage and load capacity.

By way of example, we decode the sequence “225/45 R 18 95 H SSR MOE”. The number “225” stands for the width of the tyre in millimetres – so, in this case, the tyre is 225 mm wide. The “45” that follows is the aspect ratio – the height of the tyre sidewall as a percentage of its width, which equates to 101 mm for this tyre. Next up is an “R”, which means “radial” – derived from the structure of the layers in the casing of the tyre, which run radially, or 90-degrees to the tyre circumference. The figure “18” indicates the wheel rim diameter in inches, while “95” is the load index, indicating the maximum weight the tyre can bear. In this example, the tyre is rated for 650 kg.Then comes the letter “H” which is the speed index, where “H” indicates a maximum speed of 210 km/h. “SSR” identifies that this is a Continental “Self Supporting Runflat” tyre, otherwise shown as “RF” or “Runflat”.

The abbreviation “MOE” tells us this is a Mercedes original equipment tyre with runflat properties (E = extended mobility). The number of these manufacturer-specific codes is set to rise even further in years to come as more and more automakers submit their own unique specifications to the leading tyre manufacturers.

Additional markings High-performance tyres often include “XL” after the size marking, or the word “Reinforced” on the sidewall. This refers to tyres with additional sidewall reinforcements, which are designed to cope with the additional forces created by high-speed driving, cornering, braking or load-carrying ability. “FR” is used on tyres with a flange rib, which incorporates additional rim protection features.

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