If you’ve decided MotoGP is the sport for you, perhaps you’ve watched a couple of races, picked a favorite rider or two – now it’s time to take your love of MotoGP to the next level and expand your knowledge.
Many forces are at play between a MotoGP bike and its tires.
But how big are these powerful wheels?
We break down everything you need to know about the size, types, temperature and pressure of MotoGP tires and how they withstand the force during a Grand Prix weekend.
What Tire Size is Used in MotoGP?
Michelin is the sole tire provider for the MotoGP class, providing every rider with two types of tires: Power Slick tires for dry conditions and Power Rain tires for wet conditions.
The same size tire is used for all MotoGP bikes: 120/70 ZR 17 for the front and 180/55/ ZR 17 for the rear.
Front Tire Specs
- Size: 120/70 ZR 17
- Type: Radial (R)
- Width: 120mm
- Rim Diameter: 17″
- Speed Rating: Z (149mph +)
- Aspect ratio: 70%
Rear Tire Specs
- Size: 180/55/ ZR 17
- Construction: Radial (R)
- Width: 180mm
- Rim Diameter: 17″
- Speed Rating: Z (149mph +)
- Aspect Ratio: 55%
What Do These Numbers Mean?
The first number in tire size indicates the nominal width.
The width of a tire is calculated by measuring in a straight line from the furthest point on one sidewall, across the tread, to the opposite sidewall.
Aspect ratio is used to describe the tire’s cross-sectional profile.
A smaller number means a lower profile, and the height-to-width ratio is shown as a percentage.
Tire speed rating indicates the maximum speed a tire can be used based on maximum load and inflation pressure.
Z-rated tires have no recognized maximum speed – this rating is for more than 149mph.
There are two options for tire construction: Belted (B) or Radial (R).
The rim diameter is the size of the rim/wheel (in inches) on which the tire will be mounted.
What Types of Tires Are Used In MotoGP?
So, what can riders have for selection each race weekend?
For each Grand Prix, Michelin transports hundreds of tires specifically designed for that track and the most common temperatures on the day the race is held.
For dry conditions, each rider is provided with 22 tires – a set of 10 fronts and 12 rears.
These 22 tires come in three compounds, Soft, Medium and Hard.
Each team must select a maximum of five tires of each front compound, while the rear tire allocation can be made up by selecting a maximum of 6 softs, 4 mediums and 3 hards.
The Michelin Power Slicks are formulated to provide maximum grip when taking corners and braking.
Tires can be of single or dual compound construction, but this will depend on the track layout and temperature.
For wet conditions, each rider is provided with 13 tires – 6 fronts and 7 rears.
Teams can choose between soft or medium compound rain tires.
The Michelin Power Rain tires have a tread that maximizes rubber-to-surface contact by expelling standing water from the tire’s contact patch.
The tread continues to the shoulder of the tire, allowing riders to maintain a high lean angle in corners.
The Temperature and Pressure Parameters of a MotoGP Tire
Each MotoGP tire is designed to deliver top performance and durability on the MotoGP grid within specific temperature and pressure parameters.
Analyzing this data is fundamental, and you’ll often see Michelin specialists reading temperature measurements during a race weekend.
The best pressure for MotoGP tires is around 2 bars for the front and 1.8 for the rear.
This pressure is generated with dry air so that the internal pressure does not change as the temperature increases.
To avoid the pressure being inaccurate and affecting performance, pressure sensors are mounted inside each tire.
Michelin also sets a temperature standard that the tire must be heated to before use.
Tires must be heated to 194°F (90°C) before they can go on track.
Ideal performance and operating temperatures of the tires on track are around 212°F (100°C) for the front and over 248°F (120°C) for the rear.
However, there is a thin line between an optimal tire temperature and overheating the tires.
When tires overheat, whether from aggressive driving or a high track temperature, they can blister or grain, significantly reducing grip and overall performance.
Similarly, if the tires are too cold, they won’t reach their full grip potential, and the bike will start to slide.
What Forces Can a MotoGP Tire Withstand?
Given that tires are the only point of contact a bike has with the ground, MotoGP tires have to withstand the force generated by the engine, brakes, weight transfer and the rider’s movements.
To get an idea of the type of punishment these tires are put through, consider this: when accelerating on a straight line, the rear tire can withstand over 2,200 Newtons (224 kg) of force.
The front tire withstands 2,500 Newtons (254 kg) of force with hard braking up to 1.5.
On turns, lateral forces can exceed 2,000 Newtons (203 kg) of force.
While the tires are enduring these forces, they must maintain their shape without any deformation.
This is why pressure is so important and thoroughly studied by Michelin.
Temperature and pressure parameters are set in place to prevent accidents and help riders achieve optimal race performance.
Understanding this element of MotoGP adds an extra level to watching the race.
The Michelin-made and supplied 120/70 ZR 17 front tires and 180/55/ ZR 17 rear tires give riders a set of powerful wheels.
Depending on the track conditions of the race day, these come as either slicks or rain tires.
And with the right heat and pressure, riders have optimal racing performance when they hit the track.