Hyper Tyres — The Mobile Tyre Company

How to Read Your Tyre Size: A Complete Guide

Learn what 205/55R16 91V means, where to find your vehicle's correct tyre size, and how to check load ratings, speed ratings and replacement fitment in NZ.

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The short answer

In 205/55R16 91V, 205 is the nominal width in millimetres, 55 is the sidewall height as a percentage of that width, R means radial construction and 16 is the rim diameter in inches; 91 and V are the load and speed codes. Find your vehicle's approved specification in its tyre placard or owner's manual, then check the complete replacement specification, including any different front and rear sizes, rather than choosing by wheel diameter alone.

Compare the full sidewall code with your vehicle's tyre placard or owner's manual before ordering.
Keep the required load and speed ratings, plus any specified Extra Load or specialist tyre construction.
Have a tyre specialist check rim compatibility, clearance and NZ requirements before changing size.

Questions drivers often ask

Does the 55 in 205/55R16 mean the sidewall is 55 mm high?

No. It means the nominal sidewall height is 55% of the tyre's nominal 205 mm width: 112.75 mm. The same 55 aspect ratio on a wider tyre gives a taller sidewall, so the ratio cannot be read as a fixed height.

Can my front and rear tyres have different sizes?

Yes, if your vehicle manufacturer specifies a staggered front/rear fitment. Check both axle specifications in the placard or manual. NZTA requires tyres on the same axle to have the same size designation, construction and tread pattern type; that does not mean every vehicle needs the same size on all four wheels.

What does XL mean, and does it let me carry more in my car?

XL means Extra Load: the tyre has a higher load capacity than a standard tyre of the same dimensions under the specified conditions. Retain XL if the vehicle requires it and check the actual load index. Fitting a higher-rated tyre does not increase your vehicle's permitted weight or axle loads, and XL does not prescribe a single inflation pressure.

Sources and further reading

Updated 4 November 2026