Speed rating and pressure

Speed rating (T, H, V, W, Y) is the tyre’s tested maximum speed at a given load. It is not a pressure table. A V-rated 18-inch tyre on a Mondeo still uses the Mondeo placard.

Fitting a lower speed rating than original equipment can be a legal and insurance problem in the UK even if the pressure is perfect. Matching or exceeding the OEM symbol is the usual rule, with winter-tyre exceptions in some handbooks.

High-speed touring at the legal limit on a correctly inflated tyre is what the rating already assumed. Adding 5 psi “for the autoroute” is a myth unless the maker printed a high-speed column.

Run-flats and OE performance tyres may have their own footnotes. Read them. Do not invent a track pressure for the school run.

If you changed both size and speed rating, you now need the load table and the vehicle placard, not a forum average.