Every tyre carries a size marking on its sidewall — for example, 205/55 R16 91V. Understanding what each part of this code means helps you confirm you have the right tyres fitted and allows you to order correctly when speaking to a mobile tyre fitter in Leeds.
The Width (e.g. 205)
The first three-digit number is the tyre's section width in millimetres, measured from sidewall to sidewall. A wider tyre offers more grip but can increase fuel consumption slightly.
The Aspect Ratio (e.g. 55)
This is the tyre's profile height expressed as a percentage of the width. A 55 profile means the sidewall height is 55% of 205mm. Lower numbers mean a lower-profile tyre — these handle sharply but ride more firmly and are more vulnerable to pothole damage.
The Construction and Rim Diameter (e.g. R16)
The "R" stands for Radial — the standard construction for modern car tyres. The number that follows (16) is the diameter of the wheel rim in inches that the tyre is designed to fit.
Load Index and Speed Rating (e.g. 91V)
The load index (91) indicates the maximum load the tyre can carry — in this case, 615kg. The speed rating (V) indicates the maximum speed the tyre is certified for — V-rated tyres are rated to 149mph. Never fit a tyre with a lower speed rating than your vehicle's original specification.
Why Getting the Size Right Matters
Fitting the wrong tyre size affects speedometer accuracy, handling, fuel economy, and in some cases invalidates your insurance. When you call Pegasus Mobile Tyres, we'll confirm the correct size for your specific make and model before we arrive.
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