Speedster!

Some people describe the golden era of motor racing as a time when tires were skinny and drivers were fat. While that saying may earn a laugh or two, the truth is that today’s race tires ARE fatter—and stickier—than their earlier counterparts. It’s hard to argue with physics, and wider tires do deliver more grip, the associated fat fender flares be damned.

However, a vintage race tire with contemporary looks—and modern handling characteristics—has arrived. The name on the sidewall? Hoosier Racing Tire, no stranger to the world of competition rubber.

Who Is Hoosier?

In the world of tire manufacturers, Hoosier is a true mom-and-pop organization. The company was founded in 1957 by a young circle track racer named Robert “Bob” Newton and his wife, Joyce, who started out recapping street tires with stickier rubber. The Newtons set up shop in an abandoned horse barn located in South Bend, Ind., and their initial clients were other Midwestern racers.

In 1962, thanks to an arrangement with the Mohawk Rubber Company, Hoosier began making their own tires. Hoosier faced one of their first big obstacles in 1978, however, when they received word that Mohawk was closing the plant that had been building the race tires.

The Newtons decided to take production in-house, opening their own factory a year later. After initially sourcing their rubber from outside suppliers, Hoosier brought this aspect of tire production in-house in 1985. Around this time, the company started to look beyond oval track and drag racing, and hired Bruce Foss as a sports car manager in 1984.

Fast-forward another 20-something years, and things are going well for Hoosier. Their tires are still made in the U.S., as the company now resides in a sprawling complex located in Plymouth, Ind.

Bob and Joyce Newton are still involved with the company’s operations, and under Foss’s leadership the company’s sports car program has allowed Hoosier to become a dominant force in both amateur and professional road racing, autocross and vintage competition. Hoosier is now the sole tire supplier for the Grand American Road Racing Association—the sanctioning body for the Rolex 24 At Daytona, among other professional races.

Back to the Drawing Board

According to Mike Kraemer, Hoosier Racing Tire Product Manager, the seeds for a new vintage race tire were planted about six years ago. “That was about the time that the tire options for Porsche Speedsters became a bit of a problem,” he explains. “Since then, we have kept an eye on the market. More recently, the issue became even more difficult and the calls became even more frequent from racers looking for tires to go racing.”

While Hoosier already had a vintage-friendly bias-ply tire in their catalog, the company felt that racers campaigning older sports cars could benefit from a dose of modern technology. “Since most of the cars in this market ‘grew up’ on bias-ply, the introduction of radial tires to the market went against the purist grain,” Kraemer says. “The reality of the circumstances are that the radial tire is a much more reliable tire to use. It is easier and more consistent to drive and far less likely to have trouble and fatigue out when properly used.” For the engineers at Hoosier, the decision to move vintage racers to a radial tire was one of safety. Since vintage race drivers are generally allowed to run modern helmets, harnesses, fire-suppression systems and the like, Kraemer reasons, why not up-to-date tires? “Tires fall into the same category [as traditional safety gear],” he explains. “If we can supply a safer product, then we should take advantage of the opportunity.” The new vintage race model, appropriately named the Speedster, uses construction similar to that found in the company’s spec tire for the Grand-Am Cup series. The Grand-Am Cup is a professional endurance road racing series, and the spec Hoosier tire was designed to be progressive, long-wearing and easy to drive. The tire also has to work with some cars that hit the scales at nearly a ton and a half, such as the Porsche 996, BMW M3, Ford Mustang GT and Cadillac CTS-V.

“The Hoosier tire is an outstanding tire for wear and consistency,” explains 27-year-old Wayne Nonnamaker, a three-time Grand-Am Cup champion who is also a regular contributor to Grassroots Motorsports. “We can run very long stints with the tires with little degradation.”

His Team Sahlen plans usually enters five or six cars at each Grand-Am Cup race, so they’re no stranger to the tire. “There is a definite spike in the first three laps of amazing grip that then falls off rapidly, but once you lose that initial magic grip the tire doesn’t change for one to three hours of running, depending on the car and [whether the tires are] fronts or rears,” Nonnamaker says.

He has found that the tire has nice breakaway characteristics, making it easier to drive. “Some tires can have great grip right up until losing all of [their] grip, which makes a car very much like driving on a knife edge. These aren’t like that.”

While Hoosier’s Grand-Am Cup tire is nearly a slick, the Speedster gets a vintage-looking tread and sidewall. The currently available sizes of 185/65R15, 205/60R15 and 225/50R15 are also tailored more for vintage iron and were chosen to cover the Porsche 356, early Porsche 911 and various Triumph and Alfa Romeo models. Hoosier is considering applications for 13-inch wheels, but they’re waiting to see how the vintage race market reacts to the initial sizes.

The Speedster does carry approval from the Department of Transportation, but Hoosier doesn’t recommending using the tire for street use. At least initially, these tires will only be available from Hoosier racing tire dealers. Suggested retail prices range from $149 to $164 per tire depending on size.

What to Expect

Vintage racers who are already regularly running radial tires, like those in Porsche Speedsters, probably won’t have to make any real changes when going to the new Hoosier, Kraemer explains. Those who have been on bias-ply tires may have to make a few adjustments.

“Some of the Triumphs and Alfa Romeos will need to do some tuning,” he explains. “The most obvious tweak is to increase the negative camber a bit.

“The biggest adjustment will be in driving style. The transition from bias-ply to radial is sometimes difficult because of the way the tires work. The feedback and responses that drivers learn to feel change quite a bit.” For those who are going to switch from bias-ply to radial tires, Kraemer has some advice, although he cautions that each car will be a little different, especially as many vintage race cars were not designed to run on radials. At a minimum, he says that he would initially add 1 degree of negative camber to the existing setup when going to radials.

As far as tire pressures, these will depend on the particular car. “For Speedsters, I would recommend beginning with 24 to 26 psi cold in the rear and 22 to 24 cold in the front. With Triumphs and Alfas, I would start 22 to 25 cold. Hot pressure should be 10 to 12 psi higher.” Tire temperatures should be in the 180- to 220-degree Fahrenheit range.

Out on track, the radials will offer a different feel, Kraemer explains, as they like to operate at much lower slip angles. “It also means all the indicators that drivers subliminally feel are changed,” he adds. “In many ways, bias-ply tires are more fun to drive because it allows for tail-out cornering and car control while drifting through the corner. A radial tire prefers to be driven in a tidy and controlled way. The corner speeds are higher when it is all done right, but the feel of speed is less intense.”

Testing Time

Talk and theory are one thing, but we wanted to see how the new radial Hoosier Speedster behaved on track on a real vintage race car. So we loaded up trailer and our gear and headed to Georgia’s Roebling Road Raceway, a 2.02-mile track that is popular with both vintage and club racers.

We would be comparing a fresh set of 5.50-15 Hoosier Vintage T.D. bias-ply tires against the 185/65R15 Hoosier Speedster on our 1957 Triumph TR3 vintage racer. Our chief mechanic and usual co-driver, J.K. Jackson, served as our test driver.

Before we began the official test, both sets of tires were scrubbed in and allowed to sit for 24 hours. This initial heat cycle can often extend the life of race tires, as the weak bonds within the rubber are broken and then allowed to reform as stronger bonds.

We used an A-B-A testing scheme for our tire comparison, with the first and third track sessions on the radials and the middle session on our bias-ply tires. This would allow us to get used to the new Speedster and confirm that the conditions weren’t changing dramatically throughout the two hours of testing. The first session on the new tires was our worst of the day. We started with 25 psi all around in our cold tires, and this quickly proved to be problematic on the left-front tire as the pressures rose to just under 30 psi. J.K. noted that the car developed a strong push (understeer) after just a few laps on the Speedsters. Our first average on this tire was a 1:35.396, which was several seconds off our typical lap times on this challenging course. Basically, the car just didn’t want to turn.

As the car cooled down, we bolted on the Vintage T.D. tires and set them at our normal pressures: 26 psi cold front and rear, which climbs to about 29 psi when hot. J.K. quickly settled into a rhythm of 1:32 laps, with an average of 1:32.661.

For our third session, we bolted the Speedsters back onto our trusty TR3 and set the pressures quite a bit lower, this time at less than 20 psi cold. We then went out for a warm-up lap. We brought the car back in once the tires were hot and set the pressures at 24 psi.

J.K. found that this pressure worked much better for the track and conditions, and started rolling out very strong laps. He set his fastest lap of the day on the Speedsters, recording a 1:32 flat. The new tire’s second session average, 1:32.449, was quite a bit faster than its first.

It doesn’t take a math major to see that the Speedster beat our tried and true bias-ply tire after just two sessions. Just a small pressure tweak brought the Speedster’s times in line with, and then below, our old favorite, the Vintage T.D., even with that persistent push.

To get a better idea of how the new tire was working, we checked the tire temperatures with our Longacre digital pyrometer. Interestingly, the outside edge of our left-front tire was approaching 170 degrees, while the inside edge of the same tire struggled to reach 70 degrees. (And this was on a brisk 55-degree day.) These temperatures are a clear indication that some suspension tweaks will need to be made to take advantage of the Speedster’s radial construction. As expected, the radial tire needs considerably more negative camber than the 1.5 degrees that we currently have on our TR3.

While we have installed slotted upper control arms to get the negative camber that we currently have, we’ll need to break out our die-grinder once again to get even more. Based upon the temperatures, we expect that our TR3 will need closer to 3.5 degrees total negative camber to get the temperatures in check and help our lap times even more.

Parting Thoughts

Although we tried to run the Speedster that most closely matched our regular tire size, we did run into a few variables that anyone shopping the new tires will need to address.

The 185/65R15 Speedster we tested has a tread width that is almost identical to the 5.50-15 Vintage T.D. we had been running, but the newer tire has a slightly squarer profile. As a result, the radial tire’s section width—the overall width of the tire—is actually slightly narrower. The tire weights are close, as the Speedster checks in at 15.9 pounds while the Vintage T.D. weighs 16.6 pounds.

Once both tires are mounted and inflated, the 185/65R15 Speedster also has a considerably shorter overall diameter than the 5.50-15 Vintage T.D. The change in gearing caused by the shorter Speedster tires certainly didn’t hurt our times at this track, but might become a factor on faster tracks like Road Atlanta. While we might have been able to squeeze the taller and wider 205/60R15-sized Speedster onto our 15x5.5-inch Panasport wheels, the rear fenders of our TR3 probably would have taken a beating.

The Speedster tires are brand-new, and we’re just getting used to them, so look for updates in future issues. In the pursuit of speed, we might just have to try those wider tires after all.

Resources

Hoosier Racing Tire (574) 784-3152

Longacre Racing Products (800) 423-3110

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