Emmanuel Thierry Sales Engineer Vaisala Paris France Vaisala Humidity Measurement in Formula 1 Tires play a central role in the perfor- mance of all cars, but Formula 1 races have especially “educated” the gen- eral public about the importance of choosing the right tire. Humidity is an important parameter for tire pres- sure. Michelin, the world leading tire manufacturer, has chosen Vaisala The test court at Clermont-Ferrand is products to measure humidity in the at the core of F1 tire Formula 1 tires it manufactures. development. he world-famous tire 1970s. Michelin was active in the as Michelin wanted to measure manufacturer Michelin discipline for 10 years, winning the humidity in its tires. T was founded in 1889 but world championships with Fer- Humidity is a very important its origins date back to the 1830s. rari and McLaren and pioneering parameter for pressure. The tires Michelin produces tires for pas- the use of radial tires. However, are inflated at an ambient temper- senger cars, trucks, other vehicles the company decided to with- ature, but during races the tire and aircraft, as well as map and draw from F1 at the end of the temperatures rise to some 100°C, guiding services through its 1984 season. The company made and sometimes up to 120°C. In tourism services product line. its comeback to F1 in 2000. At laboratory conditions Michelin Currently Michelin Group has present Michelin cooperates with has tested tires at even higher “Humidity has its say in how tires more than 125,000 employees all five F1 teams (Renault, Jaguar, temperatures, up to some 150°C. function,” says Pierre Fabry, but he over the world. With their com- McLaren Mercedes, Toyota and According to Mr. Fabry, humidi- does not reveal all of his secrets. petition department, Michelin is BMW Williams). ty in tires has several sources and also present in motor sports, in- the objective was to determine cluding the World Rally Cham- Humidity plays where exactly the humidity nologies, extremely important in pionship, Moto GP, Le Mans a role in tires comes from. This would help in overall car industry develop- and Formula 1. Engineer Pierre Fabry of Miche- finding a solution to tackle this ment,” explains Fabry. Michelin first started in For- lin is responsible for Renault F1 major problem. “But the very val- mula 1 in the middle of the Team tires. He contacted Vaisala ue of humidity in tires is confi- Demanding environ- dential. After all, we mental conditions are working in the The Vaisala HUMICAP® Rela- Formula 1 world, tive Humidity and Temperature which represents the Transmitter HMP238 was cho- most advanced tech- sen to make these measure- ments, since conditions are de- manding. There is a pressure of around 1.5 bar along with high temperatures. The product was Much of the perfor- mance and speed of used with options such as calcu- F1 cars depends on lation to determine all the para- the tires. For different meters of humidity. Michelin is weather conditions, using this transmitter as a Michelin produces portable transmitter to test three different types of everywhere in the world. The F1 tires: dry, interme- HMP238 performed well in the diate and wet. A Vaisala HMP238 tests, assisting Michelin in the transmitter measur- development of ever better tires ing humidity in tires. for the fastest motor sport. G 14 163/2003.