MotoGP racing bikes can reach blistering speeds on the straights and corners during a race. All the forces at play are transferred from the bike through the tires onto the track surface. This makes the tires a vital part of the bike, but what size tire is used in MotoGP?
The size of the racing tire used on a MotoGP motorbike is a 120/70 ZR 17 front tire and a 180/55 ZR 17 rear tire. Michelin is the sole tire manufacturer for MotoGP. They supply racing slicks for dry track conditions and rain tires with treads for wet track conditions.
Read on to discover the size, compounds, pressures, and temperatures of MotoGP tires and the forces they are subjected to during a race.
What Is Tire Size Used In MotoGP?
MotoGP racing bikes use Michelin Power Slicks for dry track conditions, and Power Rain treaded tires for wet conditions. All MotoGP bikes use the exact size tire from Michelin; these are 120/70 ZR 17 for the front tire and 180/55/ ZR 17 for the rear tire. But what do these numbers mean:
|Tire Size||120/70/ZR 17||180/55/ ZR 17|
|Aspect ratio (tire wall height)||70%||55%|
|Speed rating||Z (149mph +)||Z (149mph +)|
|Tire type||R (Radial)||R (Radial)|
|Rim Diameter||17 inch||17 Inch|
- The tire width is the first number and represents the nominal width of the tire. It is measured in a straight line from sidewall to sidewall across the tire’s contact patch.
- The aspect ratio is the cross-sectional profile of the tire. The smaller the number is, the lower the profile of the tire wall. The number shows the profile as a percentage of the tire’s width. E.G. 70% of 120mm (tire width) = 58mm side wall height
- The tire speed rating is the highest speed the tire can be subjected to under maximum load while at the correct inflated pressure. The “Z” rating is for speeds of 149mph and above with no maximum speed.
- The tire type is either a “B” for belted or “R” for radial construction
- The tire rim diameter is the size of the rim/wheel that the tire can be mounted to.
What Are The Different Tire Types Used In MotoGP
Michelin is the sole tire supplier for MotoGP. Michelin’s contract was extended by MotoGP to supply tires till the end of the 2026 racing season. Two basic types of tires are issued to the MotoGP racing teams at a race. The first type is slick tires (Michelin Power Slick) used in dry racing conditions.
Michelin has several different compound types that are used in their tires. Still, they are narrowed down to three categories, soft, medium, and hard compounds. The teams receive 10 front slick and 12 rear slick tires for a race weekend and can select which compounds they want to use.
The teams can select one of the following options:
- Seven soft and five medium tires
- Seven medium and five hard tires
- Seven soft and five hard tires
The Michelin Power Slicks are designed to supply maximum grip while leaning into turns and braking. The exact recipe used by Michelin is a closely guarded secret, but the main ingredient used is Carbon Black. The tire can have a single or dual compound construction, this is track dependent as temperature, and track layout will influence this.
Michelin takes all these factors and designs a tire to suit the criteria of each race track on the MotoGP calendar. For instance, if a track has more right-hand corners, the right shoulder of the tire will be made slightly harder for durability. If the track temperature is low, they will have a softer compound to supply more grip.
The second type of tire is a rain tire (Michelin Power Rain) used for wet track conditions. The MotoGP teams will receive 6 front and 7 rear tires and also have a choice between soft or medium compound rain tires.
The teams can select one of the following options:
- Three soft and four medium rain tires
- Four soft and three medium rain tire
The Michelin Power Rain tire has a tread that will expel standing water away from the tire’s contact patch to achieve maximum rubber-to-surface contact. The tread on the rain tire continues onto the shoulders of the tire so that the rider can still achieve high lean angles in the turns.
The Temperature And Pressures Of A MotoGP Tire
MotoGP tires are designed to supply top performance at a very specific set of temperatures and pressures. It is very common to see a specialist from Michelin taking a reading from the tires during a race weekend so that they can improve their product.
MotoGP tire pressures are constantly monitored with pressure sensors mounted inside the tire. The recommended pressure for the tires is 2 bar for the front and 1.8 bar for the rear tires. The tires are filled with dry air (0% moisture) as this has less heat/pressure fluctuation characteristics.
Michelin has set a specific temperature that the tire must be heated with the aid of tire blankets. The tire must be heated to 90°C (194°F) before it can go on track. While on track, the front tire can heat up to 100 °C (212°F), and the rear tire can reach 120°C (246°F).
There is a fine line between optimal temperature and overheating the tires. Overheating occurs from 135°C (275°F), causing the tire to start blistering or grain, reducing the overall performance and grip. Overheating is caused by aggressive riding and track temperature.
What Forces Can A MotoGP Tire Endure
A MotoGP tire has to cope with the force generated by the engine, braking, the rider’s movements, and the bike’s weight. All these forces are transmitted through the tire while maintaining contact with the track surface.
While accelerating on a straight section, the tire must withstand a force of 224 kg (2200 Newton). During braking up to 1.5 g, the front tire withstands 254kg (2500 Newton) of force. When the bike is in a turn, the lateral forces can exceed 204kg (2000 Newton).
While all these forces are passing through the tire, it must maintain its shape without deforming in any way. This is only possible if the correct tire pressures are used. If the pressure is too high, the tire may burst, and if the pressure is too low, the tire will climb off the rim.
MotoGP uses a 120/70 ZR 17 front tire and a 180/55/ ZR 17 Rear tire manufactured by Michelin Tires. The tires issued to the teams are either slick or rain tires, depending on the track conditions. MotoGP tires need to be heated and have the correct pressures to perform optimally on track.