# Council Decision of 26 June 2001 on the accession of the European Community to Regulation 108 of the United Nations Economic Commission for Europe concerning the approval for the production of retreaded pneumatic tyres for motor vehicles and their trailers (2001/509/EC), Division 7.1.2.1: The theoretical outer diameter of a retreaded tyre shall be calculated by the following formula:


D = d + 2H
where:
D: is the theoretical outer diameter in millimetres;
d: is the conventional number defined in paragraph 2.21.3, in millimetres;
H: is nominal section height in millimetres and is equal to S n multiplied by 0,01 Ra where:
where:
S n : is the nominal section width in millimetres;
Ra: is the nominal aspect ratio.
All of the above symbols are as quoted in the tyre size designation as shown on the sidewall of the tyre in conformity with the requirements of paragraph 3.2.2 and as defined in paragraph 2.21.

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Source: https://www.legislation.gov.uk/eudn/2001/509/attachment/1/division/7./division/7.1.2.1. (the official version)
Page: https://openlegislation.uk/eu-decision-2001-509/attachment-1/division-7./division-7.1.2.1.
Contains public sector information licensed under the Open Government Licence v3.0. Source: legislation.gov.uk, The National Archives.