June 8, 2018
Today’s Extreme Performance Summer tires deliver traction and handling that just a few years ago was only matched by true race tires. The category continues to expand, but it seems we have reached a performance plateau. With every new tire announced, we secretly hope it will be "the one" that disrupts the status quo and resets our expectations of what is possible from a 200 treadwear street tire. Whether it be a new benchmark for outright speed around the track, or perhaps a tire that is as fast as the current top offerings but delivers ride and noise comfort previously unheard of from the category, or even a monumental jump in wear or wet traction, we’re waiting to be amazed.
The Dunlop Direzza ZIII is the next version of an old favorite, utilizing a new compound, modified tread pattern and updated internal construction to enhance handling and traction in the pursuit of faster laps.
The Falken Azenis RT615K+ takes an evolutionary step beyond its predecessor with the adoption of Falken’s latest, motorsports-derived compound the company claims improves grip in both dry and wet conditions.
The Bridgestone Potenza RE-71R’s impressive package of performance attributes has made it the current gold standard for the category, and the Hankook Ventus R-S4 is a go-to choice for endurance racers thanks to its fast pace and remarkable wear characteristics. To see if one of the new Extreme Performance Summer tires can leapfrog the established leaders, the Tire Rack team conducted a Real World Road Ride and Performance Track Drive comparing all four tires. Our evaluation used 2017 BMW F36 430i sedans fitted with new, full tread depth 245/40R18 tires mounted on 18x8 wheels.
Our 1/3-mile per lap test track course includes 90-degree street corners, a five-cone slalom and simulated expressway ramps. Run in both dry and wet conditions, the test track allows our team to experience the traction, responsiveness, handling and drivability normally only encountered during abrupt emergency avoidance maneuvers or competition events.
Track and autocross use are two of the primary goals for Extreme Performance Summer tires, which has made tires from the category the primary choice for racing series such as American Endurance Racing, ChampCar, and 24 Hours of LeMons, in addition to open track lapping days. For competitive autocross, the SCCA and many other sanctioning bodies require a minimum 200 treadwear rating to run in "street tire" classes, making Extreme Performance Summer tires the hot ticket for national and regional level competitors, as well. This competition focus also makes them very fun to test in the dry, and the best in the category are surprisingly capable in the wet, too.
The Bridgestone Potenza RE-71R sets the bar in the dry, both objectively and subjectively. Crisp steering response and strong front-end authority handle requests for directional changes with ease, and the immense lateral grip helps carry a high rate of speed through turns. Applying the brakes delivers both excellent modulation and confident deceleration, as evidenced by the shortest 50-0 mph stopping distance in the test. The Dunlop Direzza ZIII was hot on the Bridgestone’s heels every step of the way, so closely matching the leader for feel that one tester remarked that without knowing which tire was on the car, the Dunlop could easily be mistaken for the Bridgestone. Objective performance between the two is also close, with a scant .09 second separating the average lap times. The Falken Azenis RT615K+ isn’t the fastest tire in the test, but it is the easiest to drive fast. Even when overdriven, the Falken provides gentle, audible and tactile correction, never punishing a driver for his or her mistakes. Only .01 second separates the Hankook Ventus R-S4 from the Bridgestone, but the two tires are very different in feel. When driving the Hankook, steering inputs are initially met was an almost exaggeratedly immediate response that isn’t directly proportionate to the input. It is just as easy to place the vehicle where you want it as with any of the other tires, but the non-linearity feels rubbery or elastic-like and takes some acclimation.
In the wet, the Potenza RE-71R stole the show. We are still amazed by the grip the Bridgestone’s compound delivers and the confidence it inspires. Like virtually all Extreme Performance Summer tires, the low-void tread pattern does not efficiently evacuate standing water, so hydroplaning resistance is challenged, but wet traction is competitive with some of the best we have ever tested. The Direzza ZIII is very capable in its own right, and is likely to satisfy most any driver in damp to wet conditions. The updated compound of the Azenis RT615K+ makes a big improvement in wet traction compared to its predecessor, and the easy-to-drive personality we felt in the dry carries over to the wet. The Ventus R-S4 has strong lateral grip, as evidenced by its second-place performance on the skidpad, but it trailed the group by a small margin in braking and average lap times.
Our 6.5-mile loop of expressway, state highway and county roads provides a great variety of road conditions that include city and highway speeds, smooth and coarse concrete, as well as new and patched asphalt. This route allows our team to experience noise comfort, ride quality and everyday handling, just as you would during your drive to school or work.
Extreme Performance Summer tires are developed as street tires, so they can be daily driven in warm weather. However, their concentrated focus on track performance and fast lap times means anyone seeking serene refinement for their commuter vehicle would be better served by a tire from a different category.
The low-void tread design of the Potenza RE-71R creates a discordant mixture of sounds over all surfaces, and the stiff construction means even the smallest impacts are felt in the cabin. The Direzza ZIII is nearly as loud as the Bridgestone in terms of tread noise, but impact noise is much more subdued, and the ride is surprisingly compliant for such a performance-oriented product. Tread growl dominates the aural experience with the Azenis RT615K+, and the firmest ride in the group means impacts can border on harsh. The ride quality of the Ventus R-S4 falls in the middle of the pack, and the tread creates a whirring sound at all speeds, with some testers stating they could feel the interaction between the tread and the road surface through the steering wheel in the form of a tactile vibration at low speeds.
Any driver willing to tolerate the noise and rough ride of an Extreme Performance Summer tire is rewarded with responsive handling and traction in turns exceeding anything that can be prudently exploited on the street. The Potenza RE-71R continues to lead the category in this area, with exact, perfectly-weighted steering and reflexes that are just right. Dunlop’s entry adheres to this model, too, feeling very similar to the Bridgestone but with slightly lighter steering effort. The Azenis RT615K+ takes a little more input than the Bridgestone or Dunlop before it builds any real weight in the steering, but it is linear and precise from there. One common complaint from our testers concerns the lack of self-aligning torque from the Falken tires, which feels a little out of place in a tire of this caliber and ultimately hurt the overall handling score. Steering feel was a topic of conversation with the Ventus R-S4, as well, due to its non-linear response to inputs that created a very urgent, but rubbery character.
Our Real World Road Ride features a relatively flat 6.5-mile loop of 65 mph expressway, 55 mph state highway and 40 mph county roads along with three stop signs every lap. Our team drove each tire approximately 500 miles over the course of several days. Since we wanted to compare fuel consumption results that typical drivers would experience, our drivers were instructed to maintain the flow of traffic by running at the posted speed limits and sustain the vehicle’s speed using cruise control whenever possible. They did not use hypermiling techniques to influence vehicle fuel economy.
| Tire | Test MPG* | Gallons/Year @ 15,000 Miles |
% vs. Most Efficient |
|---|---|---|---|
| Bridgestone Potenza RE-71R | 29.2 | 513.7 | - |
| Dunlop Direzza ZIII | 29.1 | 515.5 | -.3% |
| Falken Azenis RT615K+ | 28.9 | 519.0 | -1.0% |
| Hankook Ventus R-S4 | 29.2 | 513.7 | - |
| *Our evaluation used Race Technology DL1 data loggers to record true distance traveled. | |||
Low rolling resistance is rarely a consideration when discussing Extreme Performance Summer tires, and we recorded only a slight difference in observed vehicle fuel economy. The .3 mile per gallon disparity between our lowest and highest observed fuel economy would result in an additional 5.3 gallons of premium gasoline used per year.
It’s important to note our test’s fuel consumption measurements follow consistent procedures designed to minimize variables that could influence the results; however, they do not represent an exhaustive long-range fuel consumption study. While our procedures require the test vehicles in each convoy to run under the same prevailing conditions, the week-to-week differences in ambient temperatures, barometric pressures and wind speeds that we experience over a season of testing can influence vehicle fuel consumption and prevent the absolute mpg values of this test from being compared directly against those of others.
Larger differences in consumption between tires may indicate a difference that might be experienced on the road, while smaller differences should be considered equivalent. As they say, your mileage may vary.
We’re eagerly waiting for a manufacturer to release an Extreme Performance Summer tire that really blows us away with its combination of attributes. The new tires evaluated in this test have made measurable improvements over their predecessors that bring them closer to the top of the category, but the bar hasn’t been reset. So although that means at the moment we’re still waiting, the number of great tires in the category continues to increase, and with the surprising variety of traits and personalities from such a focused group of products, enthusiasts of all types can find a tire that suits their needs.
The Bridgestone Potenza RE-71R is once again our testers’ choice for the category. Intrusive noise and a jarring ride on the road are quickly forgotten when chasing a new lap record, threading through a slalom or attacking a twisty back road, which, rain or shine, is where this tire truly excels. The Dunlop Direzza ZIII nearly matches the leader’s pace on our dry track and is surprisingly comfortable on the road relative to the other tires here, but its wet traction is a noticeable step back from the best. The Falken Azenis RT615K+ is easy to drive up to and at the limit, and would be a great option for open track days. It can’t quite match the lap times of the other tires here, and its on-road handling, while impressive, doesn’t win over our drivers. For the second time, the Hankook Ventus R-S4 has essentially tied the Bridgestone for the fastest average lap, with noticeably less perceptible wear after testing was finished. Wet traction is above average, and the on-road performance is characterized by oddly non-linear steering response and palpable noise at low speeds.
Bridgestone Potenza RE-71R (Extreme Performance Summer): The Potenza RE-71R is an Extreme Performance Summer tire developed for serious sports car, sports coupe and performance sedan driving enthusiasts looking for Bridgestone’s fastest DOT-legal street radial. Starting with a clean-sheet approach and a virtual slick tread, all of the design features were fine-tuned to maximize performance, traction, handling and control. Performance-tuned for dry and damp conditions, the Potenza RE-71R, like all Extreme Performance Summer tires, are not intended to be serviced, stored or driven in near- and below-freezing temperatures, through snow or on ice. Read more.
Dunlop Direzza ZIII (Extreme Performance Summer): The Direzza ZIII is Dunlop’s Extreme Performance Summer tire designed for the drivers of sports cars, performance sedans and track day vehicles who are looking for near motorsports levels of traction and handling in a tire that can be driven on the street, in addition to autocross, drifting and track day events. Tuned for maximum performance in warm, dry and damp conditions, the Direzza ZIII is not intended to be serviced, stored, nor driven in near- and below-freezing temperatures, through snow or on ice. Read more.
Falken Azenis RT615K+ (Extreme Performance Summer): The Azenis RT615K+ is a further evolution of Falken Tire’s championship-winning Extreme Performance Summer tire, the Azenis RT615K. Developed for drivers of muscle cars, sports cars, street rods and performance sedans who want ultimate grip in warm, dry and wet conditions, the Azenis RT615K+ is not intended to be serviced, stored nor driven in near- or below-freezing temperatures, through snow or on ice. Read more.
Hankook Ventus R-S4 (Extreme Performance Summer): The Ventus R-S4 (Z232) is Hankook’s Extreme Performance Summer tire developed for the drivers of sports cars, sports coupes and performance sedans looking for near-motorsports levels of grip for track events, autocross and drifting in a tire that can be driven on the street. Like all summer tires, the Ventus R-S4 is not intended to be serviced, stored nor driven in near- and below-freezing temperatures, through snow or on ice. Read more.
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