Motorcycle and scooter tyres: the answers

In the size 120/70 ZR17, 120 is the section width in millimetres, 70 the ratio of sidewall height to width as a percentage, R indicates radial construction (ZR indicates a radial designed for high speeds) and 17 the rim diameter in inches. Load index and speed code follow in brackets, for example (73W), where W indicates over 270 km/h. The marking M/C indicates a motorcycle tyre. The sizes to fit are those approved by the manufacturer and shown on the registration document.

Sources: michelin.it

In a radial the casing plies radiate from the centre of the wheel and a belt reinforces the top; it offers comfort at high speeds and suits powerful and sports motorcycles. In a bias the plies are crossed and the structure is homogeneous, with stiffer sidewalls: it suits small or medium displacement motorcycles at moderate speeds. In the size you recognise them by R (radial), dash (bias) or B (belted bias). Except for exceptions given by the manufacturer, radial and non-radial are not combined on the same motorcycle.

Sources: michelin.it, michelin.it

It is a size in inches, used mainly on older motorcycles: 3.00 indicates the section width in inches, the dash the bias construction and 18 the rim diameter in inches. The height/width ratio is not shown. Michelin publishes a conversion table: for example 3.00 corresponds approximately to 80/90 or 90/90 in millimetres. The table however is not a legal equivalence: the sizes fitted must be those approved by the manufacturer and shown on the registration document.

Sources: michelin.it

Yes, as a rule front and rear have different sizes and characteristics, and the registration document gives the size for each wheel. Manufacturers develop their ranges to work as a pair: Michelin strongly recommends fitting tyres of the same range front and rear. Respect the markings printed on the sidewall, such as any direction of rotation. Check and replace each tyre according to its actual condition (wear, damage, age), not necessarily both together.

Sources: michelin.it, michelin.it

Manufacturers divide motorcycle ranges by use: road and touring, sport, track, off-road (enduro and motocross) and scooter. Competition tyres often carry the marking NHS (Not for Highway Service), meaning they are not approved for road use. For enduro and motocross there are dedicated sizes. The choice depends on the motorcycle, use and riding style, but the size must stay the one approved by the manufacturer. The tyre fitter can help you choose the range.

Sources: michelin.it

They should be inflated to the pressure recommended by the motorcycle manufacturer, referring to cold tyres: you find it in the owner's manual or on the vehicle's labels. Front and rear have different values, and the manufacturer may give different values with a passenger or luggage. Measure the pressure with cold tyres using a reliable gauge, regularly and before trips. Wrong pressure worsens grip and speeds up wear.

Sources: michelin.it, pirelli.com

Yes. To release tyres from the mould, products are used that leave a shiny film on the surface, and until it disappears grip is reduced. Michelin recommends setting off gently, accelerating and braking smoothly, leaning over little and gradually increasing the loads for at least 100 km, on different types of road. In low temperatures running in takes longer. Do not use abrasive products to remove the film and check that the pressure is the one recommended by the motorcycle manufacturer.

Sources: michelin.it

There is no mileage valid for everyone: lifespan depends on the motorcycle, riding style and conditions of use. Michelin recommends a monthly check of tread depth, pressure and damage. They must be replaced when the tread reaches the wear indicators, or in case of bulges, deformations, punctures or cracking. Abnormal wear is also a sign: in the centre it often indicates pressure too high, on the shoulders pressure too low. If in doubt, have the tyre assessed by a specialist.

Sources: michelin.it, michelin.it

Yes, rubber ages even when the tyre is not used. The production date is read in the last four digits of the DOT code: week and year (for example 2523 = week 25 of 2023). For tyres in general, Michelin recommends a check by a specialist at least once a year after 5 years of use and precautionary replacement 10 years after production. Continental also states that tyres older than ten years should be replaced. A barely used tyre is not necessarily in good condition.

Sources: michelin.it, michelin.it, continental-tyres.co.uk, pirelli.com

Yes, if they are in good condition and correctly inflated, but in the wet grip is in any case lower than on dry roads. You need gentle throttle and braking, reduced lean angles and longer distances. Worn tread and wrong pressure worsen grip, and pressure must be kept at the value given by the manufacturer. Competition tyres (marked NHS) are not approved for the road. For frequent use in the rain ask the tyre fitter for a range suited to your motorcycle.

Sources: michelin.it, michelin.it

You need tyres in the size approved by the manufacturer and shown on the scooter's registration document, for example 120/70-12 or 110/70-13: the rim diameter varies from model to model. Also consult the owner's manual for any additional indications. Check that the chosen range is available in your size and that load index and speed code match those specified. There are ranges dedicated to scooters, also for classic models with 8 or 10 inch rims.

Sources: michelin.it

It depends on the rim. A TT (Tube Type) tyre is not airtight and always requires the inner tube. A TT rim, like most spoked rims, which have holes in the centre, requires the inner tube; however, tubeless spoked rims exist. Continental states that one of its tubeless tyres can go on a tube-type rim only with an inner tube of the right size, while a tube-type tyre must not be fitted on a tubeless rim. Check the TL/TT markings on tyre and rim.

Sources: michelin.it, continental-pneumatici.it

You can, but manufacturers advise against it: ranges are developed to offer the best combination between front and rear, and Michelin strongly recommends using the same brand and the same range front and rear. Except for exceptions given by the motorcycle manufacturer, a radial is never fitted together with a non-radial. The construction (R, B or dash) is part of the size shown on the registration document and must be respected. If in doubt ask the tyre fitter.

Sources: michelin.it, michelin.it

The reference is the sizes approved by the manufacturer and shown on the registration document: respecting the original sizes is essential for safety. Michelin states that its conversion tables between inch and millimetre sizes are not a legal equivalence. Changing width or diameter can alter dimensions, speedometer and the motorcycle's behaviour. Before ordering a different size check the motorcycle's documentation and ask the manufacturer or the tyre fitter.

Sources: michelin.it, michelin.it

Many classic motorcycles use sizes in inches (for example 3.00-18), often with bias construction. Today the standard is in millimetres, with the rim diameter kept in inches, and for many obsolete sizes there are alternatives: Michelin publishes an inch-millimetre conversion table, which however does not count as a legal equivalence. You need the original size, the type of rim (inner tube or tubeless) and the manufacturer's indications. Old tyres must be checked even if they have few kilometres.

Sources: michelin.it, michelin.it

Not necessarily: electric motorcycles and scooters also use tyres in the size and with the load and speed indexes specified by the manufacturer and shown on the registration document. Some manufacturers offer ranges designed for electric scooters, but the choice must respect the vehicle's approval. Pressure, wear and damage are checked as on any motorcycle. For the choice of range ask the tyre fitter.

Sources: michelin.it

Michelin does not offer snow tyres for motorcycles: it considers that the safety problems of a motorcycle on a snowy or icy road, where it is easy to lose balance, cannot be solved by the tyre, and advises avoiding riding in these conditions. In the cold, grip on dry tarmac also decreases, because the tyre struggles to reach operating temperature. If you use the motorcycle in winter, keep the pressure recommended by the manufacturer and check wear carefully.

Sources: michelin.it

The wheel is mounted on a balancer and imbalances are compensated with counterweights. An unbalanced wheel can cause vibrations, handlebar oscillation, instability and uneven wear. Pirelli recommends balancing the wheel every time the tyre is fitted on a new rim or demounted and refitted, and when these symptoms appear. The job must be done by a specialist, paying attention to discs, callipers and sensors.

Sources: pirelli.com

As a rule yes: many tyre shops fit the tyre on the wheel you bring already removed. Removing and refitting the wheel, however, requires skill: axle, spacers, brake discs and tightening torques must be respected according to the motorcycle's workshop manual. Bring the wheel clean and mention any pressure sensors. Ask the tyre fitter first whether they accept a loose wheel. If you have no experience, it is safer to have the removal done by a workshop.

Not all: many motorcycles do not have a tyre pressure monitoring system (TPMS) as standard, but aftermarket systems with similar functions exist. Sensors can be mounted on the valve or built into the wheel and measure pressure and, in some cases, temperature. If your motorcycle has one, tell the tyre fitter, because the sensor needs care during removal and fitting. TPMS does not replace the periodic check with a gauge.

Sources: pirelli.com