What does speed rating T mean?

190 km/h, in the part of the table that behaves itself

Between Q and U the speed symbols increase in flat 10 km/h steps: Q is 160, R is 170, S is 180, T is 190, U is 200. T therefore has an easy relationship with its neighbours — one letter down is 10 km/h less, one letter up is 10 km/h more, with no exceptions to remember. That regularity disappears further up the chart, where the increments jump to 30 km/h and one letter is out of alphabetical position entirely.

A rating almost nothing reaches

118 mph is well beyond the sustained capability of most vehicles that arrive on T-rated tires, and beyond the legal limit almost everywhere they are driven. The symbol is not a target. It records a construction standard: what the casing survived on a test machine at a set load and pressure, run in steps up to that speed. A tire that is under-inflated, damaged or carrying more than its rated load is outside the conditions the letter was awarded under, whatever is printed on it.

Where T shows up

It is the workaday marking of family sedans and vans, and of a great many all-season and touring patterns. The same vehicle is frequently offered with H-rated tires in a sportier trim and with a lower symbol again on winter rubber, because a compound built for cold weather is not built for the heat that a high-speed test generates. Those are three different tires for one car, and the symbol is the shorthand for which is which.

Reading it on the sidewall

T never appears alone: it is the last character of the service description, immediately after the load index. Feed a complete one to the decoder and both halves come back separately, or read the whole series in the speed rating table.