ZR in the size (225/45 ZR17) and (Y) in brackets
ZR marks a radial tyre for speeds above 240 km/h, rated W or Y. With the service description in brackets, like (94Y), the tyre is for more than 300 km/h and its maker states the actual top speed.
What to do with it
Read the letter after the load index for the rating — ZR alone is not a speed. For a bracketed (Y) tyre, the maximum speed and the load allowed at it come from the tyre maker, so ask them; the regulation has that figure notified at approval rather than moulded as a symbol.
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- What it looks like
- ZR in place of R inside the size — 225/45 ZR17 94Y — and sometimes the load index and Y inside brackets: (94Y).
- Set by
- UN Regulation No. 30, paragraphs 3.1.3.4, 3.1.4.1 and 5.3.1
In detail
- UN R30, 3.1.3.4: on radial tyres for 240–300 km/h (speed symbol W or Y) “the letter ‘R’ … may be replaced with the inscription ‘ZR’”. It is optional: a W or Y tyre can also say plain R.
- UN R30, 3.1.4.1: above 300 km/h ZR is required and the service description, speed symbol Y with its load index, is marked in brackets.
- 225/45 ZR17 94Y XL decodes as: 225 mm wide, 45 % sidewall, radial for high speed, 17-inch rim, 670 kg per tyre, 300 km/h, extra load.
What it does not mean
ZR is not a separate speed category and does not by itself give a top speed; a Z is not a speed symbol in the table.
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 3.1.3.4, 3.1.4.1 and 5.3.1: “On tyres suitable for speeds in excess of 300 km/h, the letter ‘R’ … shall be replaced by the inscription ‘ZR’ and the tyre shall be marked with a service description consisting of the speed symbol ‘Y’ and the corresponding load index … within brackets, for example, ‘(95Y)’.” Checked 2026-09-28.