Tire mixing on same axle prohibited
Recently, the subject of tire fitting has taken up front pages and articles in specialized magazines, with interpretations, observations or requests that prompted us to clarify first of all what the current legislation prescribes. The answer has always been the same: the obligation of fitting the same tires on each axle is confirmed, i.e. tires of the same "type", which includes the same manufacturer or trade mark. Starting from the Highway Code: where motor vehicle equipment devices, including tires, are concerned (article 72), it is specified that if the technical requirements relating to construction and functional characteristics and assembly refer to devices covered by Community directives, these directives apply; alternatively, the technical requirements contained in the regulations or recommendations issued by the European Office for United Nations - Economic Commission for Europe (acronyms: UN/ECE) apply. On the one hand, the vehicle manufacturer must indicate for the tires, in the vehicle type approval specs, the size, load index and (minimum) speed code necessary, without mentioning any specific brand to ensure competition and free choice for the user. As far as all the characteristics of the tires themselves and in particular fitting them on the vehicle, since the 1980s international directives and regulations have been applied, with known and consolidated requirements, which regulate all the aspects that could affect road safety (behaviour/balance of the vehicle when cornering, braking, etc.). The subject, initially regulated by UN/ECE regulations, was reorganised in 1992 with Directive 92/23/EEC dated 31 March 1992, which came into force in Italy with Decree 30/3/ 1994, which specified, in the tire fitting requirements and in the definitions: all tires mounted on the same axle must be of the same type. "Type meaning a category of tires that does not differ in the following key aspects: the manufacturer’s name or trade mark, size designation, category of use: road/special/ snow/temporary use, structure (bias-ply, cross-ply, radial-ply), speed category, load-capacity index, cross-section. Subsequently, Regulation (EC) No 661/2009 issued by the European Parliament and the Council dated 13 July 2009 concerning type-approval requirements for the general safety of motor vehicles, their trailers and systems, components and separate technical units intended therefore to provided, among other things, that that Directive expired at the end of 2017, and that reference would be made to the existing EU Regulations, or to the UN/ECE or UNECE Regulations in force, and/or its implementing provisions”. The definition “type of tire” has remained unchanged, with the addition of a “class” of tires (C1, C2, C3) according to the type of vehicle for which they are intended, and the requirement for fitting them has remained unchanged. More specifically, Annex II to Commission Regulation (EU) No 458/2011 dated 12 May 2011 concerning type-approval requirements for motor vehicles and their respective trailers with regard to the installation of tires and implementing Regulation (EC) No 661/2009 of the European Parliament state:
2. Tire Fitment
2.1. All tires normally fitted to the vehicle, thus excluding any temporary-use spare unit, shall have the same structure.
2.2. All of the tires normally fitted to one axle shall be of the same type.
In addition to the above, our Ministry of Transport, with DM 628 issued in 1996 on vehicle testing procedures and periodic inspection, specifies among the requirements: "the verification of the identity of the tread pattern of the tires on at least the same axle". It is therefore further confirmed that the tires of the same axle must be of the same make/manufacturer, while it is not compulsory to have the same make on all the axles of the vehicle. The use of the "normal" spare wheel, with a tire of the same size and load/speed characteristics as the others fitted to the vehicle, is permitted even if of different make and design for dèpannage situations, as are the tires for temporary use, specifically provided for and limited in their use by the Regulations in force. In the case of retreaded tires, only the brand of the retreader, the "new" tire manufacturer, within the meaning of Regulations 108 and 109, counts, and not the brand of origin of the retreaded tires.