Where to find them
A tyre may be marked in a form such as 205/55R16 91V. The 91 is the load index and the V is the speed symbol.
Load index
The load index is a code that corresponds to a maximum load for one tyre under specified conditions. Do not replace a tyre with a lower load capability than the vehicle requires.
Speed rating
The speed symbol is a performance category established under tyre standards. It should match the vehicle manufacturer’s required specification and intended use.
Why this matters when shopping
Two tyres with the same 205/55R16 size can carry different service descriptions. That means “same size” does not always mean “same specification.”
Practical buying rule
Send Thunder Skylight a photo or the complete sidewall marking if you are unsure. The exact specification is more useful than only sending the rim size.