It is often by dissecting the photos that we discover interesting subjects concerning the techniques used in MotoGP. This time, it is a simple tire temperature sensor mounted on the rims of the Ducati team since 2017, and Yamaha Movistar this year. System ultimately not that simple!
Until now, and this is still the case, manufacturers used infrared sensors mounted on the swingarm to record tire temperatures, starting with those of the rear casing which has the difficult task of having to keep the motorcycle on its wheels while passing the power to the ground. Two, three, or even five sensors are therefore mounted on the swinging arm, generally under the mudguard and pointing towards the tire to measure its temperature by detecting the infrared rays emitted by it.
Here are some examples. For technical data, you can consult the site Texense.
This year, the official Yamaha team also used 3 identical sensors in its front mudguards, for the same purpose.
This practice has existed for a very long time, but, following various incidents, the obligation then came to mount pressure sensors in the rims, in order to prevent certain teams from lowering the pressure of the rear tires too much, certainly to gain grip, but at the risk of overheating and deterioration of the pneumatic casing.
As a result, “dual sensors” appeared, measuring both the internal pressure and the temperature of the tire, supplied mainly by the company 2D, well known in the racing world. As a reminder, it is also thanks to these sensors that you can see which tires are used on MotoGP live on television (the unique signal from each sensor is recovered by loops in the asphalt).
Then Ducati, which was already working with accelerometers McLaren, was the first in MotoGP to introduce the British firm's sensors, the latter having the particularity of measuring the temperature in 5 different locations, compared to only one for the 2D.
These are the same infrared sensors that Yamaha and KTM now use on their official machines, easier to implement than 5 external sensors connected by electrical wires. For the moment, however, we keep these, if only to calibrate and/or see the temperature differences between the inside of the carcass and the outside of the rubber...
The complete system consists of a pressure sensor and an infrared temperature sensor with transmitter mounted on a rim. This sends pressure and temperature data via a radio link to a compact receiver. A single receiver is used to receive data from the front and rear tire sensors. The sampling rates automatically increase depending on the condition of the tires and the sensor stops below a pressure threshold to preserve battery life (same if the wheel does not turn, in their latest version ). The receiver sends the data to the motorcycle via CAN.
We will remember that once again, as is very often the case in the technical field, Ducati was ahead of its little comrades...
wheel sensor
- Supply voltage 2,8 – 3,6 V (internal thionyl chloride and lithium battery)
- Lifespan >1 transmissions
- Number of transmissions included in transmitted data
- Battery voltage measured at full charge
- Transmission Rate: Governed by the rate of change of pressure, temperature and impeller rotation. Structured to preserve battery life.
Tire pressure
- Pressure range 0,3 – 7 bar (4,4 – 100 psi)
- Pressure resolution 4mBar/bit (0.06psi/bit)
- Pressure accuracy ±10mBar (±0,15psi) typical, ±20mBar (±0.3psi) max
- Self-compensated over temperature range
Tire temperature (infrared array sensor)
- Object temperature -20°C to +300°C
- 120° field of view
- 5 tire temperature points (T1 – T5)
- Temperature resolution 0.078°C/bit
- Temperature accuracy ±3°C
- Repeatability ±1°C
Credit technical documents: McLaren
