After the size (like 205/55R16), most tire sidewalls carry two more codes: a load index (a number, like 91) and a speed rating (a letter, like V). Both describe real operating limits, and both should match or exceed your vehicle manufacturer’s specification — not just “seem close enough.”
Load index: a code, not a direct weight
The load index is a standardized number that corresponds to a maximum load in kilograms that a single tire can carry when properly inflated. The numbers don’t map 1-to-1 to kilograms in an obvious way — a load index of 91 corresponds to a specific published weight in the standard load index tables, higher numbers meaning higher capacity. What matters practically: your vehicle’s manufacturer specifies a minimum load index for a reason tied to the vehicle’s weight and safety margins, and going below it is not a safe substitution even if the tire otherwise fits.
Why load index matters more for commercial and heavier vehicles
For an ordinary passenger car, factory-specified tires typically already carry enough margin for everyday use. It matters more directly for vans, pickups, and any vehicle that regularly carries heavy loads or tows — running a lower load index than specified under real cargo weight increases the risk of tire failure under load, heat buildup, and blowouts. This is a genuine safety specification, not a minor detail, for fleet and commercial vehicles especially.
Speed rating: a sustained-speed capability, not a target
The speed rating letter indicates the maximum speed a tire can sustain safely under its full rated load. Common ratings include (from lower to higher): Q, R, S, T, H, V, W, Y. A vehicle manufacturer specifies a minimum speed rating for the vehicle’s realistic performance envelope. Fitting a lower-rated tire than specified is a real reduction in the tire’s safety margin at speed, even if you don’t personally drive at the tire’s rated maximum — heat buildup and structural behavior at highway speeds are affected by the rating, not just top-speed capability.
Where to check what your vehicle actually needs
The correct load index and speed rating for your vehicle are specified alongside the tire size on your door-jamb sticker or in the owner’s manual — the same source you’d use to confirm tire size. If that information isn’t legible or available, we can help cross-reference a reasonable match based on your vehicle’s documented specifications, but we won’t guess a load index for a commercial vehicle carrying unknown loads — that’s a conversation worth having directly, especially for fleet and business accounts.
Buying with the right specification
Go Mina’s catalog shows load index and speed rating information where available per product — browse by size or message us your door-sticker details on WhatsApp for a confirmed match.