It's hard to believe it's been two decades since Dwayne "Big Daddy" Gutridge first showed us that Mustangs rule the strip on DOT-approved radial tires. Yes, 1989 was the year that drag radials made their way onto the street/strip scene. Twenty years later, radials are widely recognized as the tires of choice for hard-hitting Ponies that put in work on the boulevards and the 1,320.
Initially, only one tire company manufactured drag-radial tires. While that rubber was street legal, the radials were employed at drag-racing events more often than on the street. (Did you know that the first official "class" for drag radials was called Heads Up Radial, and events were held at Raceway Park in Englishtown, New Jersey?)
Since the 'Stang that was...
Since the 'Stang that was originally slated for this exercise, our '02 Mustang GT, rides on American Muscle's 17x10.5-inch FR500 wheels in street trim, our intent was to keep things consistent (from an appearance and weight perspective) by mounting both sets of test drag radials on the same wheels that adorn our project ride. Armando Espinosa's crew at A and A Tires & Wheels in Reseda, California, took care of the musical-tires mounting and balancing procedures for us.
One of the things we dig about this Mustang game is that the quest for big steam seems to be a never-ending endeavor for most of us. Enthusiasts throughout the 'Stang Nation are always experimenting with methods of improving performance; aftermarket companies, in turn, are always working on methods of improving their wares. When one manufacturer raises the bar by improving a particular part or component, its competitors usually follow in short order as nobody in this game ever wants to be outdone.
Nitto Tire jumped into the drag-radial fray several years ago with the introduction of the NT555R Extreme Drag Radial. The Triple 5R gained a loyal following among 'Stangbangers who needed more traction from their high-horse street Stallions. This loyalty is largely due to the 555R's best-of-both-worlds characteristics: excellent treadwear on the street and grip on the strip. Of course, balancing traction and treadwear leaves some traction on the table.
On the left is Nitto's NT555R...
On the left is Nitto's NT555R drag radial; the NT05R is on the right. While both tires are 315/35R-17s, there is a pretty dramatic difference in their tread pattern and height. The new DR's tread is a lot more track-specific than its street predecessor. It also is slightly taller thanks to its increased sidewall. The additional side area is stiffer, which Nitto says helps minimize instability at high-speed/top-end.
As drag radials go, the NT555R proved to be perfect for dual-duty Ponies that have as much as 500 hp at the feet. The addition of drag-radial classes in many of the heads-up racing sanctions, and the big-horsepower cars in those classes, brought about a need for Nitto to add a new street-legal DR to its already-extensive lineup of tires for Mustangs-one that is capable of handling more rear-wheel horses. That led Nitto to develop a stickier drag-radial targeted specifically at competition events.
We had our first look at NT05 technology in 2008 when your tech editor visited Nitto's Itami Technical Center in Japan. At that time, the non-drag-radial NT05 street tire was in its final stages of testing, and based on the close-to-final version that KJ viewed, it was clear that a street tire with road-race-tire attitude would soon be with us. It only made sense that a drag radial would follow.
So, with that said, we welcome the all-new NT05R drag radial! Also in the works since 2008, the NT05R is the newest drag radial on the Mustang scene. It's the result of Nitto's extensive research, development, and testing efforts to produce a DR that is built to hook big steam on the street, and especially on the quarter-mile.
Here's a look at both versions...
Here's a look at both versions of Nitto's NT05 tire, the street tire at left and NT05R drag radial on the right. As you can see, the NT05R shares a somewhat similar tread pattern as its street sibling. From an overall construction standpoint, the shoulder treads and center ribs on each tire differ the most. While the DR has a much wider center section and softer compound for maximum grip with the strip, the NT05 street tire features a reinforced shoulder for improved rigidity and stability in dry-road, high-speed driving conditions. The tires are alike in that they're both not the most-comfortable or quietest tires in Nitto's street and competition families. Tire noise is considerable from both, especially when driving in 65- to 70-mph freeway conditions.
"Our top priority during the development of the tire was to maximize traction," says Nitto's Stephen Leu. "To achieve this, engineers developed an all-new specialized race compound and a large contact patch for the NT05R, and enhanced its sidewall." The new drag radial's sidewall enhancement (a bit more sidewall, and much stiffer than sidewalls of NT555R and NT05 street tire) is dual purpose, for traction during launch as well as straight-line stability at the top-end. "The dual-purpose of the NT05R's sidewall helps improve consistency and controllability throughout an entire pass," says Stephen.
After receiving a set of the new boots, our plan was to give them a try at the Pacific Street Car Association's Spring Break Super Show event at Auto Club Dragway in Fontana, California. A and A Tires & Wheels of Reseda, California, mounted 315/35R-17 NT555Rs and the same-size NT05Rs on two pairs of American Muscle's replica FR500 wheels, and we set out to make some laps with Jerome Citrolo's 475hp, nitrous-injected '03 Mach 1
The NT05R's dual-purpose sidewall...
The NT05R's dual-purpose sidewall construction is enhanced for traction during launch, as well as straight-line stability at the top-end. This improves consistency and controllability throughout a full quarter-mile pass.
At the track, we consulted...
At the track, we consulted with Jerome Citrolo (a Los Angeles-area 'Stang racer who has considerable experience with Nitto's original drag radials, having used the NT555Rs on his nitrous-injected Mach 1) and cut him loose with both sets of test Nittos to evaluate their 60-foot and 300-foot performance on his Pony. Per Jerome's suggestion and the cool track temperature at Auto Club Dragway on Saturday, we would initially start with 14 psi of air (cold) and a 5,000-rpm launch with each drag radial, and adjust (up or down) from that baseline.
After collecting data with...
After collecting data with the NT555R drag radials, we made the swap over to the NT05Rs and kept hopes high for better short-time success with the race-ready radials.
From a street perspective, the new DRs definitely are as good at holding the road as their street siblings. We put extensive mileage on the tires in normal street-driving, freeway, and desolate-area/full-blast conditions. They performed well-the only thing we'd be a little reserved about is driving on the NT05R drag radials beyond 5,000 miles (the new tires have a 0 treadware rating) and in extremely wet conditions.
The NT05R's soft compound really is not conducive to the same type of regular operation as the street version, so the tires may be more "limited-use" for budget-conscious enthusiasts than those with deeper pockets. Pricing for the NT05Rs is said to be comparable to the cost of Triple 5s.
Comparative photos of the NT555R, NT05, and new NT05R Nitto tires are next, along with our critical 60-foot and 330-foot dragstrip data for the company's original drag radial and its long-anticipated NT05R DRs.
On The Dragstrip
Jerome heats the hides! Heavy-smoke...
Jerome heats the hides! Heavy-smoke burnouts are recommended for brand-new Nitto DRs. The NT555R drag radials are mounted in this photo.
While we acknowledge the object of a drag race is to cover the quarter-mile as quickly as possible, the primary focus of this test is to evaluate the type of traction that Nitto's first-generation and latest drag-radial tires promote in the first 60 feet and 330 feet of the track.
"How does it hook?" is a drag racer's biggest question whenever a new racing tire is introduced. To find out just how well the Nittos hook, we called on Jerome Citrolo of Simi Valley, California, and his '03 Mach 1. Jerome's daily driven Mach is impressively modded with a stout DOHC bullet that features Ford Racing Performance Parts' aluminum big-bore block, a Mach 1 crank, Manley rods, Diamond pistons (10.2:1), '03 heads worked by Boss330 Racing, custom cams designed by Modular Performance, and a trick Nazty Performance short-runner intake manifold.
The combination is good for putting 475 hp to the feet, and Jerome is borderline obsessive about taking his Pony to the dragstrip whenever possible, attempting to achieve new personal-best e.t. and mph results at every outing. One of the good things about using Jerome for this particular exercise is his consistency as a driver. He knows his car and has extensive experience driving it on drag radials.
Track and tire temperatures...
Track and tire temperatures were measured using Actron's hand-held IR thermometer (PN CP7875; $30). The budget-friendly, pocket-sized instrument records temps ranging from -27ºF to +480ºF and provides more than 30 hours of continued service on a single battery. On Sunday, with ambient trackside temperature in the mid-70s, we saw track-surface temperature of 94 degrees and tires as hot as 187 degrees when Jerome completed his burnouts.
Nitto's first-gen drag radials...
Nitto's first-gen drag radials yielded "best" 60- and 330-foot times of 1.672 and 1.659, and 5.183 and 5.202 seconds, respectively, in two attempts on the well-prepped Auto Club Dragway. "I used to run this tire religiously on the street and track," says Jerome. "This was the first time running the NT555Rs at a track that was as well-prepped as Auto Club Dragway. I believe I could have netted a 1.620 with more practice."
We closed our test with Nitto...
We closed our test with Nitto NT05R drag radials bolted to the rear of Jerome's 'Stang. The new-style, street/'strip tires showed improved short times over the Triple-5 DRs. In two more laps, Jerome's Mach 1 covered the 60- and 330-footers in 1.643 and 1.630, and 5.120 and 5.050 seconds. "Even though this was the first time I used this tire, I believe I could have managed a 1.590 with more practice," says Jerome. "Based on the data and how the car felt when I launched, I find the NT05R to be comparable to the Mickey Thompson ET Street Radial of the same diameter."
The interesting results of our test are included in the table. We definitely intend to do more track testing with the NT05Rs, because the impressive results of our session prove that Nitto is onto something with the new drag radials. It will be interesting to see how they perform when more horsepower is applied.
|1||555R||5,000||14||1.672||5.183||Hooked and bogged|
|2||555R||6,000||13||1.659||5.202||Hooked and bogged|
|3||NT05R||6,500||15||1.643||5.120||Spun a little|
|4||NT05R||6,600||14||1.630||5.050||Simply hooked|Size Matters
Since Jerome's Mach 1 also...
Since Jerome's Mach 1 also rides on 17-inch rear wheels, we stayed with the 17x10.5-inch FR500s by AmericanMuscle.com and 315/35R17 NT05s that we selected for our test.
With late-model, hard-core street/strip 'Stangs being its target, Nitto will be rolling out its newest drag radial in 17- to 20-inch diameters throughout 2010, and included in the size lineup is a P345/30R19-the world's first 19-inch drag radial!
|Tread||Inflated Dimensions||Approved Rim||Max.|
|Depth||Overall (IN)||(Measuring Rim)||Load||Press.|
|Tire Size||(1/32-Inch)||Width||Dia.||Width (IN)||(LBS)||(PSI)|