Adding power these days is as easy as ordering a proven list of parts and adding them to your car. The same can be said of handling and braking. It’s simple to enhance your car to perform well beyond what the factory intended. If you can’t apply that performance to the road, all that effort can go to waste.

We know traction is important, which makes the tires under your performance car of supreme importance. That’s especially true of today’s enthusiast cars, which are being pushed far beyond their stock levels. That’s why Nitto Tire created a new ultra-high-performance tire designed specifically for today’s performance levels — the NT555G2.

Reinventing The Triple Five

I am amazed at just how much grip these have. — Glen Vitale, Steeda

If those three numbers in sequence sound familiar, the Nitto NT555 performance tire, also known as the Triple Five, became the tire to run in the Mustang world due to its combination of grip and tread life.

“The 555 is insanely successful for Nitto. The tire came out in 1996, so we are talking 20 years that the 555 has been around. For a tire to last that long unchanged in the market is almost unheard of,” former Nitto Tire Staff Engineer Andy W. Frank told your author when the NT555G2 debuted. “Even before we kicked this project off, we knew we wanted to play on the success the 555 had already built. We kept hearing that the 555 was a bang-for-your-buck tire. It wasn’t the greatest tire on the market, but for the performance you got at that price point, you couldn’t really touch it.”

While the original Triple Five had a great run, it really wasn’t designed for today’s power levels. Back in the day 400 horsepower was big news. Now that’s where the power starts.

“We wanted to improve it for today’s standard. Obviously the muscle car market, and cars in general, are significantly different than they were 20 years ago. Back then, 400 horsepower was a big deal, and now the new benchmark is 700 or 800 horsepower, so it’s really easy to overpower the 555,” he said. “…We simply wanted to tweak that formula to make the NT555 G2 more relevant to the modern day muscle car. …I personally like to think of the NT555 G2 as the NT555 given a heavy dose of steroids… it’s stronger, meaner, and much more aggressive.”

To arrive at that level of performance without sacrificing tread life required some science. Nitto developed a new rubber compound for the NT555G2, which balanced a traction rating of AA with an impressive treadwear rating of 320.

“As soon as the project kicked-off it was agreed that, no matter how difficult, the NT555 G2 has to grip harder, corner faster and stop shorter than the NT555 in every driving condition,” Andy explained.

The other enabler for creating a worthy successor to the NT555 was the advanced manufacturing capabilities housed inside Nitto Tire’s plant in White, Georgia. Using the automated Advanced Tire Operation Module, which is only loaded by humans, Nitto is able to control the tolerances of the tire manufacturing process within really tight tolerances, resulting in rounder, more consistent tires, which tend to wear longer.

“We viewed the NT555G2 as a bolt-on performance upgrade for the muscle car, same as a cold-air intake, exhaust or big brake kit,” Andy added. “And on top of all of this we needed a radical new design that was distinctly recognized as a Nitto tire, but still paid tribute to the predecessor NT555.”

Partner In Time

As the development of the next-gen tire progresses, Nitto turned to a familiar partner — Steeda Autosports. With the idea of creating a tire capable of harnessing modern muscle cars, the company wanted to test its tires on the cars they were meant for rather than following industry norms to test on the cars favored by mainstream media outlets.

With that in mind, it was a no-brainer to test the prototype G2 tires on a pair of Steeda S197s. Testing tires on Steeda Mustangs was what helped deliver the wildly popular NT555, so it was only fitting that these cars were the test ponies for the next-gen tire.

“It all started with the Triple Five. Nitto had an OK tire they were selling, but they wanted to take it to the next level. They also wanted to tap into the Mustang market,” Glen Vitale, Vice President at Steeda Autosports, explained. “That’s where Dario (Orlando, Steeda‘s founder and president) came in. They contacted him and said, ‘Hey, we’ve got this new tire. Would you like to try it out on one of your cars?’”

As they had in the past the Steeda team said yes and the rest, as they say, is history, which continued a streak of cooperation that had included the original NT555 as well as the open-track-oriented NT555 R2 and road-course-dedicated NT01 tires.

“They sent it to Dario. He loved it,” Glen added. “Ever since then, we have been working very closely with them to get the tires they develop to work well specifically with the Mustang. For example, with this new G2, as you know, we did a lot of testing with it on the S550 platform.”

Legendary Test Track

Your scribe was on hand for the initial testing of the NT555 G2 on the latest Mustangs. The tire is not only built to perform on dry pavement, but it excels in the wet as well. On that day it rained, so a dramatic improvement in wet performance is what we experienced by switching from the first-gen tire to the G2.

Curious about how the G2 would not only handle the dry conditions, but how it would perform on the cars that lived on the original Triple Five, we asked the Steeda Autosports team if they had an earlier ’Stang worthy of testing these tires. They produced the company’s 2001 Mustang SEMA show star, which goes by the name of the Red Rocket.

The Red Rocket Body • Steeda GT front splitter • Steeda rear wing with billet winglets Driveline • Ford Performance aluminum driveshaft • Steeda Tri-Ax shifter • Torsen 8.8 differential • Tremec TKO-500 five-speed manual w/ .82 Fifth gear Engine • Bullitt intake manifold • Custom grind cams • Paxton Novi 2000 supercharger w/ air-to-air intercooler • Stainless Works long-tube headers • Two-Valve 4.6-liter w/ forged pistons and rods Suspension • Steeda 5-Link • Steeda G-Trac Stage 1, 2, 3, and 4 • Steeda K-member • Tokico D-Spec shocks and struts

This New Edge stallion features the full array of Steeda suspension upgrades along with a Paxton supercharger under the hood. It was the perfect candidate. All we needed was an appropriate test track. The answer came in the form of an open-track day at the legendary Sebring International Raceway.

This track’s slogan is “Respect the Bumps,” so you know the surface isn’t exactly smooth as glass. This racing surface challenges both driver and hardware.

“Sebring is very challenging. Some places you are on concrete, like this concrete here, but it’s got the expansion joints. In other places its asphalt, so it’s constantly changing as the tires are going across multiple road surfaces and the driver and the tire have to adapt to that,” Glen explained.

That makes optimizing suspension and tire settings a great challenge, as the surfaces change so often, it is not consistent enough to rely on.

“Ideally, when you are racing on asphalt, you might settle on a different pressure than you would if you were running on concrete,” he added. “Here, which is one of the unique things about this place, you can’t cater to one or the other. The driver has to do the catering.”

In our case, that driver was Glen. Not only is he the company’s Vice President, but Glen is an accomplished road racer with plenty of seat time at Sebring.

On The Brakes

In order to perform apples-to-apples testing, we ordered four of each tire, the NT555 and NT555 G2, in 285/35-18 to best fit the wheels on the 2001 Steeda Mustang. To establish a baseline, we started with the first-gen tires and swapped to the G2s.

Before heading out to challenge Sebring’s bumps, we first documented the braking of the car in the paddock, accelerating to 55 mph and hitting the brakes at the same spot.

“In the brakes you can feel the difference. The butt g-meter feels like it is sticking to the ground a lot better and that’s why it’s stopping so much shorter,” Glen said. “It looked like from my standpoint, the pitch of the front end was much lower, which is good because the ABS isn’t releasing as much to keep the tire from locking up.”

During our testing, the NT555 stopped from 100 to 105 feet. After swapping tires and following the same procedure, the stopping distance dropped from 85-87 feet, yielding a solid 15-foot reduction that can really translate to better on-track performance and safety on the street.

“On the track, that braking improvement can mean the difference in getting around someone at the hairpin here where you have to brake from 130 down to 35. Those 15 extra feet mean getting around another Mustang under braking,” Glen explained.

Should the on-track performance improve, more confidence-inspiring braking will allow the driver to relax and perform better as well.

“If you can get the car whoa’d down sooner and get it pointed in the direction you want it, obviously you can get on the gas sooner, which equates to a higher top speed at the next braking zone,” he added. “That’s a big difference. If you can get the car stable where it feels planted and you can get back on the gas, that means everything. Not only can you pass under braking, but because you can get on the gas sooner, you might open up a passing situation for yourself toward the middle or end of the straightaway.”

Respect The Results

When you put your foot in it, it just accelerates like a rocket ship. — Glen Vitale, Steeda

After running our braking tests on the original Triple Fives, Glen headed out onto the track to lay down our baseline numbers. It took several laps for him to find his groove, but the feeling was definitely nostalgic, as Steeda and Glen have plenty of laps on these tires.

“It reminded me of the old days,” Glen said after driving on the NT555s. “It was kind of all over the track. I am just used to these days having so much more horsepower in these cars. This car is only pushing about 420 to the rear wheels, which naturally aspirated is what these (S550 GTs) are doing, but this one felt like it had 600 horsepower. When you put your foot in it, it would spin the rear tires.”

Despite the limited traction, Glen was able to make the car work like a skilled driver can. He laid down a 2:51.84-second lap with an average speed of 76.2 mph on the NT-555s, which was a great showing for the venerable rubber.

“I think the 2:51 for what this car has is a respectable time. I was hoping to break into the .40s with it. I was looking back at what we used to do with the R2s, and we actually did a lot of the initial testing of the R2s in this car, and we were running .46s,” Glen enthused. “That is pretty respectable for a tire that doesn’t have anywhere near the tire softness of the NT-555R2. And, the R2s were made for this kind of event, while these tires are obviously a full-on street tire, and we are putting to the test.”

With the NT-555 testing complete, Glen brought the car into the pits where Steve Chichisola and Bruce McVey swapped out the wheels and tires. With the NT-555G2s in place we tested the stopping distances again, topped off the fuel to maintain a consistent weight balance, and headed out for a Sebring test session.

The difference was eye opening. Having tested these tires on modern Mustangs in the wet, we know that Glen liked the tires, but his natural reaction after running was gleeful.

“It had a lot more grip,” Glen said with a grin. “I am amazed at just how much grip these have. It goes back to what we were talking about before and how much of a difference technology makes. It is so much more stable in the corner and it gives you so much more confidence when you are behind the wheel to be able to get on the throttle earlier and go deeper into the braking zones. I know that’s why we were so much quicker in this session versus the last session with the old tire.”

With more traction under the car, Glen was able to really maximize the on-track performance of the 2001 Steeda Mustang. His best lap was a 2:47.21 with an average speed of 76 mph, which accounted for an impressive improvement of 4.63 seconds and 2 mph from just a tire change.

“Before, when you got on the gas, the rear tires would spin, which would make it oversteer a little bit,” Glen said. “That’s not the case now. The rearend is planted. When you put your foot in it, it just accelerates like a rocket ship, which is probably why we call the car the Red Rocket. Compared to before, where you had to gently put your foot into the throttle to keep the rear tires from spinning. Otherwise, it would spin, and you would get the oversteer situation. With the G2 I was able to give it a lot more throttle input, which resulted in our quicker lap times.”

Not only was the car brisker around the track, but stopping 15 feet shorter really helped too, especially when approaching Sebring’s vaunted hairpin turn.

While the Nitto NT-555G2 is still a street tire that balances traction with reasonable wear characteristics, make no mistake – it is still a significant upgrade in performance over its storied predecessor. It is far better suited to putting down the kind of power today’s performance cars produce, which leads to more confident drivers behind the wheel.

“When the car feels planted underneath you, it does wonders for your confidence. You feel like you can get on the gas sooner. You feel like you can go deeper into the corner. You feel like you hold the wheel a bit tighter and get underneath that guy you are trying to pass,” Glen said. “If you don’t have the confidence that the car underneath you is going to grip and stick and do what you want, you are more timid and the ones who are timid usually don’t have good lap times.”

If you want better performance on the street or the track, you can learn more about the Nitto NT555G2 tires here.