Tires change along with technology
October 01, 2013, Ron LeMasters Jr., NASCAR.com
Multi-zone tread a factor on 1.5-mile tracks
Related: Mobil 1 Technology site
Another 1.5-mile track is up next for the NASCAR Sprint Cup Series, and that means there is another application of wizardry from Goodyear Tire & Rubber Co. in the offing.
Multi-zone is not the newest defense employed by football coaches. It's another example of passenger-car technology making its way back to the motorsports side.
Ten years ago, Goodyear started using multi-zone tread technology on its passenger car tires. Over the Labor Day weekend, the multi-zone made its debut at Atlanta Motor Speedway to mostly good reviews. Kansas offers the second chance for Goodyear to improve on the product and let NASCAR do that as well.
What is multi-zone? It’s two different tread compounds on the same tire. One is for grip, which is important at a track like Kansas. The other is so that the tire can live through a full fuel run.
"At Kansas ... we've recognized that the track seems to have lost some grip, but has not yet begun to wear tires."
-- Greg Stucker, director of race tires for Goodyear Tire & Rubber Co.
One big difference is track surface. Atlanta, when it was repaved 10 years ago, was wicked fast, smooth and did not eat tires like it did when the surface was aging. This past September, it was much more abrasive and harder on the tires, especially under the immense pressure of turning the car in Atlanta's long, steep corners.
Kansas, on the other hand, was repaved last year and should not have wear issues at all, or at least very little.
So why does Kansas need technology that makes the tire live longer when the surface is smooth and not the consistency of #10 sandpaper?
Greg Stucker, Goodyear’s director of race tires, said the tires were built differently using the same technology.
"Atlanta is a highly abrasive surface that wears tires quickly, but Kansas is recently paved and doesn't wear tires at all," Stucker said. "For Atlanta, we knew the Gen-6 car would be faster, thus putting more stress on the right-side tires. But, because the track surface is well worn and lacks grip, just going to a harder compound wouldn't be a good solution. As a result, the multi-zone technology enabled us to maintain the tractive compound on the outside portion of the tread and toughen up the inside 3 inches to protect the part of the right-side tire that takes the most abuse and sees the most heat."
OK, tire wear and the new Gen-6 car were the reasons for multi-zone at Atlanta.
"At Kansas, this will be the third race after the repave and we've recognized that the track seems to have lost some grip, but has not yet begun to wear tires," Stucker said. "To address that, we increased the grip on the left side of the car with a more tractive compound. With additional grip on the left, the cars will be much faster, again putting more stress on the right-side tire. So, we've utilized multi-zone tread technology to have the same compound that we’ve run there since the repave on the outside of the right-side tire to keep that level of traction, and paired it with a tougher, more heat resistant compound on the inboard three inches for endurance."
Mix-and-match for best performance is the way Goodyear is helping the new car handle and maintain the tire wear for all teams. The contact patch -- the part of the tire that is actually on the ground at any one time -- is the same size as a men’s size-11 shoe, or thereabouts.
Kansas' repaving job meant that Goodyear had to come up with a new tire, essentially, because while the carcass (the nylon frame on which the tires are constructed) is the same, it's the stuff that's baked into them that actually makes the tire work.
Neither Atlanta nor Kansas is particularly hard on brakes, but they do use them. The ever-present bead blowers are used at all tracks, and heat from the binders is particularly damning at a 1.5-mile, high-speed oval because of pressure.
Hot air expands, and to counter that, the bead blowers cut down on the amount of ambient heat that affects the nitrogen inside the tires and inner liners. Unchecked, the heat will increase tire pressure so that the driver's feel is that of driving a race car with two big balloons on the front end.
Then there's the aspect of grip. Tires provide mechanical grip, which means the weight of the car plus the G-force of its turning is what sticks it to the track. If you've ever heard the term "up out of the track," that's what it means: the cars aren't hooked to the track like they should be.
With the added aero grip -- the force of passing air pushing down on the car also known as downforce -- it creates a balancing act that Goodyear has to work around.
If the compound is too hard, it's great for cutting down on heat but lousy on getting the car to stick. Too soft, and the tire wears faster, grips better and doesn't last as long as it needs to.
That is multi-zone in a nutshell, and it will be used more and more as the technology progresses.