Load index (the 91 in 91V)
The load index is a code for the maximum mass one tyre may carry: 91 means 615 kg, 94 means 670 kg, 100 means 800 kg, read from the table in UN Regulation No. 30, Annex IV.
What to do with it
Buy tyres with a load index at least equal to what the vehicle maker specifies — it is on the tyre placard or in the handbook. Four tyres of index 91 carry up to 4 × 615 kg = 2 460 kg together, but each axle is limited by its own two tyres. The full table is on the tyre markings page, and the decoder turns any index into kg.
Read the size on your tyre: the tyre size decoder →
- What it looks like
- A two- or three-digit number straight after the size, joined to a letter: the 91 in 91V. Vans and light trucks may show two numbers, like 115/113R.
- Set by
- UN Regulation No. 30, paragraphs 2.28, 2.31, 3.1.6 and Annex IV (Load-capacity indices, 0–120); UN Regulation No. 54, paragraph 2.27 and Annex IV (60–200)
In detail
- Some values from the tables: 80 = 450 kg, 85 = 515 kg, 88 = 560 kg, 89 = 580 kg, 90 = 600 kg, 91 = 615 kg, 92 = 630 kg, 94 = 670 kg, 95 = 690 kg, 97 = 730 kg, 100 = 800 kg, 105 = 925 kg, 110 = 1 060 kg, 115 = 1 215 kg, 120 = 1 400 kg, 126 = 1 700 kg.
- The index holds at the speed of the tyre’s speed symbol up to 210 km/h. Faster, UN R30 lowers it: a V tyre on a car that can reach 240 km/h may carry 91 % of the index value, and a W tyre at 270 km/h 85 % (paragraphs 2.31.2 and 2.31.3).
- Two numbers (115/113R) are commercial-tyre indices: the first for the tyre fitted single, the second for each tyre of a twin (dual) pair — 1 215 kg and 1 150 kg. UN R54 defines them in paragraph 2.27.
- The US rule asks for the maximum load itself, in kg and lb, moulded on the tyre as well (MAX LOAD); it matches the load index at the tyre’s maximum pressure.
What it does not mean
The load index is not a weight in kilograms, and a higher number is not a stronger tyre in every way: it is only a code for maximum load, and it is not the load the tyre carries at any pressure you choose.
Markings that go with it
Sources
Each document was fetched and read on the date shown; the clause is the one that sets this marking.
- UNECE, as published in the Official Journal of the EU: UN Regulation No. 30 — Uniform provisions concerning the approval of pneumatic tyres for motor vehicles and their trailers, Revision 3 (OJ L 201, 30.7.2008) — paragraphs 2.28, 2.31, 3.1.6 and Annex IV (Load-capacity indices, 0–120): “‘Load-capacity index’ means a number associated to the reference mass a tyre can carry”; Annex IV lists each index with its mass, e.g. 91 = 615 kg, 94 = 670 kg, 100 = 800 kg. Checked 2026-09-28.
- UNECE, as published in the Official Journal of the EU: UN Regulation No. 54 — Uniform provisions concerning the approval of pneumatic tyres for commercial vehicles and their trailers (OJ L 183, 11.7.2008) — paragraph 2.27 and Annex IV (60–200): For commercial tyres the index is “one or two numbers which indicate the load the tyre can carry in single or in single and dual operation”; its Annex IV runs to index 200 (14 000 kg). Checked 2026-09-28.
- Michelin (UK): Tyre markings explained: How to read a tyre? — “How to read the maximum load and speed of a tyre?”: “The tyre load rating or load index (in our example: 91) is a code which corresponds to a maximum load (in kg) that can be carried by a single tyre.” Checked 2026-09-28.