To find out which tires are compatible with your vehicle, first check the homologated values given on the registration document / card or read, even if this is not recommended, the side / shoulder of the tires on which the vehicle or motorcycle is currently mounted is.

Check this carefully as the vehicle documents may contain both additional parameters such as “XL”, “REINFORCER”, “PR” + a number of screens (PR4, PR6, PR8), runflat, etc. alternative tires with different sizes and / or parameters , In the latter case, you can choose tires with alternative measures that already fit your vehicle. However, keep in mind that you will also need to change the rims after you have assembled them, preferably by buying them in steel or an alloy.


WIDTH (of the profile), indicated by a value in millimeters “mm” (e.g. 185, 215, 205, etc.), which can precede the letter “P” and is not influential for checking the conformity of equipment Vehicles such as 205 / 55R16 can be used in the presence of P205 / 55R16 and vice versa.

HEIGHT (the shoulder) expressed as a percentage of the width (e.g. 55, 70, 80, etc.), except for height / 80, where this marker may or may not appear, such as B. 145 / 80R13 instead of 145R13 and vice versa.

The type of construction is usually a value R (radial carcass construction) and we recall that the tires that have a speed index (S), (H), (V) or (Z) include the index in the description of the can be tires that explain the name “SR”, “HR”, “VR” or “ZR” like 225/45 ZR17. “ZR” is often found in combination with high-speed indices such as (W) or (Y).

DIAMETER (ie compatibility with the rim diameter) in inches (e.g. 16 inches, 17 inches, 18 inches, etc.). One inch corresponds to 2.54 cm: o sea 4 pulgadas = 10 cm

LOAD INDEX or the maximum load / weight that the rubber can withstand. It is identified by a number that is assigned to a numerical value in kg. The tire load multiplied by 2 must cover the total load on the vehicle axle. If the use of “REINFORCED” or “XL” tires is specified in the vehicle registration document without specifying the load capacity index, the tires fitted to the vehicle must be marked with “REINFORCED” or “XL”. On the other hand, if the wording “REINFORCED” or “XL” on the circulation document is supplemented by the specification of the load index and the symbol of the speed category, regardless of the presence or absence of such a wording, only the above provisions apply.

NB. The load index value of the tire you buy must always be equal to or greater than the homologated value on the vehicle registration / vehicle card.

INDEX OF SPEED or the maximum speed that the vehicle can reach with this tire. It is expressed by a letter that is assigned a numerical value in km / h. Depending on the different speed indices, the tires heat up less, deform less and work better at higher speeds.

NB. The speed index value of the tire you buy must always be equal to or greater than the approved value in the vehicle registration document / card, with the exception of the winter tires with the M + S marking that will be dealt with later.

IMPORTANT EXCEPTION: The tires marked for winter use (M + S / MS / MS / M & S), which are suitable for driving on snow, are subject to an exception with regard to the speed index, since they can be fitted to the vehicle models marked with a Symbol of the speed category at least “Q” for motor vehicles (corresponding to 160 km / h) and at least “J” for industrial machines. In this case, the driver must comply with the strictest limits as a standard of behavior, which may be determined by the maximum speed permitted for the tire (prescribed by a warning sign on the dashboard in the vehicle). For example, requirement 145R13 74S of the license plate number is met if the vehicle is equipped with snow tires with 145SR13 74Q M + S or 145R13 74Q M + S or P145 / 80R13 75Q M + S markings. etc.

speed codeSpeed (km / h)
 L 120
 M 130
 N 140
 P 150
 Q 160
 R 170
 S 180
 T 190
 U 200
 H 210
 V 240
 W 270
 Y 300
 ZRsur 240


  • M + S, M & S, MS, SNOWFLAKE tires (symbol) = approved winter / thermal tires that are suitable for driving with the vehicle on snow-covered roads. In Italy, this specification allows passage on roads where snow chains are required.
  •  TIRES WITH A SAFETY SYSTEM = tires with a protective edge that protects the shoulder in parking lots, for example, to prevent the rubber from being punctured / damaged or scratched from the steel or light alloy rim. Manufacturer identification codes: FP, FR, ML, MFS
  •  RECONSTRUCTED Tires = regenerated tires, also known as ecological tires, that offer services that are comparable to those of new buildings.
  •  RUNFLAT = humidifiers are tires with full anti-deflation construction technology that allow you to continue driving at a moderate speed until you reach a service center for repairs or replacements. Each manufacturer has its own identification codes:
  •  Michelin: ZP (Zero Pressure)
  •  Pirelli: Eufori @ / Run Flat
  •  Continental: SSR (Self Supporting Runflat)
  •  Goodyear: RunOnFlat
  •  Dunlop: RunOnFlat / DSST (Dunlop self-supporting tire)
  •  Bridgestone: RFT (Run Flat Technology)
  •  XL tires (extraload) or RF tires (reinforced tires) are tires that carry a higher weight load due to the material and construction, e.g. B. the reinforced shoulder.
  •  NAIL TIRES = spiked wheels are only for permanent use on long icy or snowy surfaces and do not require any additional handle devices. Traffic in Italy is only allowed from November 15th to March 15th with mounting on all 4 bikes equipped with a rear splash guard.
  •  WWW / WW / WSW (white wall) tires = car tires with one or more white stripes on the side, which is normally used for classic cars
  •  NSW / NWS / NWW tires (narrow white wall) = car tires with one or more thin white stripes on the side.

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