MONTEREY,Calif. (Feb. 7, 2002) The FedEx Championship Series presents the most diverse open-wheel action imaginable, competing on every type of paved circuit. For atire maker, it simply presents the ultimate challenge. From twisting and turning...
MONTEREY,Calif. (Feb. 7, 2002) The FedEx Championship Series presents the most diverse open-wheel action imaginable, competing on every type of paved circuit. For atire maker, it simply presents the ultimate challenge.
From twisting and turning temporary street courses to high-banked and flat-out superspeedways, Championship Auto Racing Teams drivers rely on their race tires to deliver sure-footed response on any circuit, in any conditions be it for pinpoint braking, quick acceleration or sheer consistent speed. Not many tire manufacturers possess the wherewithal or courage to take on such a challenge, but in 2002 there's a newcomer to the CART scene determined to make its mark in the FedEx series.
Bridgestone Motorsport joins competition this year as the Official Tire of CART, supplying all teams with Bridgestone Potenza racing radials throughout the 19-race campaign. The Potenzas make their public debut this weekend in CART's Sneak Preview at Mazda Raceway Laguna Seca.
"Bridgestone boasts a long and storied racing history, and we're proud to bring that heritage to CART," said Al Speyer, Executive Director of Bridgestone/Firestone Motorsports. "Bridgestone Motorsport will put to use the knowledge and expertise it has gathered in other successful racing endeavors around the globe, in order to develop the reliable tire that FedEx Championship Series drivers demand. Teams have already seen in preseason testing the dedication we have to this program and will continue to see it as Bridgestone Motorsport and CART forge this new relationship."
Bridgestone's racing history spans some four decades and all facets of the sport, from go-karts to motorcycles, touring cars to Formula One. In fact, Bridgestone-equipped teams have captured the last four Formula One driver's and constructor's championships. Utilizing a cooperative effort from its global trio of technical centers (Akron, Ohio; Tokyo and Rome), Bridgestone Motorsport will introduce the same winning technology and development to CART's top series that competes in seven countries and four continents in 2002.
The race tire development staff is well aware of the task at hand. At race speeds, the downforce created by Champ car wings and chassis can quadruple the weight the tires must carry. As cars speed up to and past 200 mph, the centrifugal force of the components, combined with lateral forces in the turns, requires enormous strength in the tire sidewalls. And on some courses, the track temperature and friction generated between the tire and track surface can cause tread to become hotter than the temperature of boiling water (212 degrees Fahrenheit).
"The Potenzas have to be thin enough to allow heat build-up to dissipate, but thick enough to shoulder the enormous stress placed on them during practice, qualifying and race sessions," Speyer said. "It's a balancing act, really, with Bridgestone Motorsport engineers and chemists constantly looking at new technologies, new materials and new methods of construction."
Track configuration plays a critical role in determining a race tire's make-up. Street and road courses tend to use a "softer" tread compound to enhance grip through the many corners and to promote better traction when a driver steps on the throttle exiting turns. Oval and superspeedway tires rely on "harder" compounds to increase durability for the long high-speed runs, as well as stiffer sidewall constructions to handle the higher g-forces and loads the tires must absorb on the banked circular tracks.
Ambient and track temperatures are also a prime consideration in tire development. The ambient temperature (the air temperature just above the track surface) can vary from the low 50s to above 100 degrees Fahrenheit. Temperatures of the track surface range from the low 50s in chilly, cloudy conditions to nearly 150 degrees in hot, sticky, sunny climates.
The track surface itself is another factor to be considered. While CART circuits consist only of asphalt, concrete or a combination of the two, their effects on tires can vary greatly due to the make-up of the surface. Local custom or regulations cause pavers to use different ingredients to make asphalt or concrete, creating a final product that may be more or less porous, slick or abrasive than elsewhere.
All these factors and the unpredictable Mother Nature must be taken into account as Bridgestone Motorsport develops and produces race tires for each venue.
"We look at all these variables when we make a determination about the best compound and construction Potenza tire to bring to an event," Speyer said. "While we can't control the weather, we are involved with how a team may set up its car for a race weekend. Our engineers work closely with teams on tire management issues, monitoring pressure levels and tread temperatures during practice, qualifying and race sessions. For safety reasons, there are minimum and maximum hot inflation levels for the tires, and we work closely with the teams and CART to see that those levels are maintained."
Every car at a FedEx Championship Series event receives the same quantity of Bridgestone tires to be used as the team sees fit for practice, qualifying and the race. The number of available sets per weekend ranges from seven for road/street courses and short ovals up to 12 for 500-mile events. Since the series doesn't stop for rain at road and street events, cars are permitted up to four sets of wet-weather Potenzas (those with a tread pattern) on those circuits.
The tires are approved and given an external code by CART officials at the track. Each tire also carries a computer barcode assigned to it by Bridgestone Motorsport, so engineers can track its performance. The tires are carefully transported, mounted and balanced by Performance Tire Service Company, with each team supplying its own wheels. Since the tires are leased and not purchased by the teams, they are returned to Bridgestone Motorsport at the end of every competition.
In all competitions, each car must start the race on tires used in qualifying. After that run usually as long as a tank of fuel lasts a car may switch to any of its other allotted sets of tires. Sometimes, though, a team may opt for a quicker pit stop late in a race by leaving on the same set of Potenzas for an extra stint, confident in the renowned durability of the Bridgestone tires.
Many teams will "scrub" in all sets that is, put a few laps on each in practice to give the tires a heat cycle. Others prefer to keep one or more sets of "sticker" tires in their pit, tires that have not been used in practice or qualifying, which may have a slightly stronger grip for a brief distance. In either case, the long-lasting tendencies of the Bridgestone Potenzas should not be affected.
Nashville-based Bridgestone/Firestone North American Tire, LLC is a subsidiary of Bridgestone/Firestone Americas Holding, Inc., whose parent company, Bridgestone Corporation, is the world's largest tire and rubber company. BFNT develops, manufactures and markets Bridgestone, Firestone, Dayton and associate and private brand tires. The company is focused on wholesale and original equipment markets, supplying passenger, light truck, commercial vehicle, off-road, agriculture and other tires to its customers in North America.