What do you value most in a motorsports tire? Grip? Longevity? Consistency? Streetability? Affordability?
What if you could have all those factors at the minor expense of some wet performance? That’s what Tire Rack’s Streetable Track and Competition category aims to deliver.
These tires feature durable tread compounds, very little squirm-producing void, and good internal puncture resistance. Just don’t get caught in a downpour.
We call these tires Endurance 100s. They’re DOT-approved yet more track-focused than the ever-popular 200tw tires. The current crop includes the Nankang Sportnex AR-1, Maxxis Victra RC-1 and Toyo Proxes RR.
We ran our usual tire setup: 245/40R15 fronts and 205/50R15 rears on 9- and 8-inch-wide 6UL wheels by 949 Racing. Several days before the test, we gave our test tires a first heat cycle, gradually bringing them up to temperature over several laps while building to an 85% effort and avoiding slipping the tread surface. In addition to scrubbing off the slippery mold release agent, this process works the internals to relink compound molecules in a stronger and more durable fashion.
Track Results
From left to right: Toyo Proxes RR, Nankang Sportnex AR-1, Maxxis Victra RC-1. Photography Credit: Andy Hollis
Nankang Sportnex AR-1
- best lap: 1:24.7
- $175 (245/40R15)
The Nankang AR-1 has found a home as a track day lapping favorite. Available in many motorsports-friendly sizes at affordable prices, it delivers a solid mix of performance and longevity.
However, our previous testing showed grip levels more on par with the current Super 200tw category than the modern, track-focused 100tw tires. NASA has recognized this fact and slotted the Nankang into a more appropriate grouping.
Since we were familiar with the AR-1 from our previous work, we ran it at both the beginning and end of the test rotation to bracket our results. It delivered strong longitudinal grip–acceleration and braking–while exhibiting predictable response characteristics. As the lap count went up, heat soaking caused some greasiness that narrowed the operational window, but careful driving minimized lap time drop-off. Our best time came on the second circuit at 1:24.7
Maxxis Victra RC-1 R2 Compound
- best lap: 1:24.4
- $209.99 (245/40R15)
When we last ran the Maxxis RC-1 through its paces back in 2014, we found a tire that was hyper-responsive to steering inputs with extremely linear characteristics as lateral forces built. Maxxis has updated the tire with a new compound, promising improvements in both grip and longevity.
Would the new compound deliver? Would the feel change for the better? In a word, yes. This new, softer R2 compound added just enough delay in the response to make it feel more normal, and grip has clearly increased.
The RC-1 turned the quickest laps of all three tires tested this time, if only by a couple of tenths. It was good in all areas, with a standout performance in the track’s severely off-camber uphill climb of Turn 5. This suggests it may be the best choice for cars with camber limitations.
Toyo Proxes RR
- best lap: 1:24.6
- $251.08 (245/40R15)
Toyo has had a long-standing partnership with NASA–see the sidebar later in this story about the impetus for this test. The brand produces the spec tire for several classes of wheel-to-wheel racing and sponsors a number of events.
In return, NASA has often favored Toyo tires from a rules standpoint. Has the sanctioning body gone too far by grouping this Hoosier look-alike with slower rubber? Turns out, no.
As the lightest tire in the bunch with the shallowest molded tread depth, the Toyo Proxes RR felt the most lively and lithe. For sure, it was quickest in combined loading, as evidenced in the full-throttle, high-speed esses leading onto the front straight and the climbing off-camber exit of Turn 7 onto the back straight. The Toyo did need a bit more heat than the others, with its quickest times coming on laps three and four, but it was very consistent: Only two-tenths separated every circuit.
Nankang Sportnex AR-1 (retest)
We bracketed our test by returning to the Nankang AR-1. Had track conditions changed significantly during the day? (This is why we generally test no more than three different tires per day.)
We found that it hadn’t, as we matched our earlier lap times. Satisfied with the veracity of the data, we loaded up to go home and study it.
Why This Test Now?
We tested a group of 100tw track tires just two years ago, running the Goodyear Supercar 3R, Pirelli Trofeo R and Nankang AR-1. But motivation for this latest test came from a recent NASA rule change for its Time Trial and Super Touring road race categories.
[Track Day Tire Test: Nankang, Goodyear and Pirelli]
NASA classifies cars using a power-to-weight formula plus multipliers for certain modifications–like the tires fitted to the car. For 2022, NASA tweaked the rules regarding tires, classifying them more by performance than anything else.
Its fastest tier (-1.0 multiplier) lumps together today’s top DOT-approved, R-comp offerings, meaning Hoosier versus the Goodyear Supercar 3R and the rest of the world. The middle group (+1.0 multiplier) features the faster 200tw tires, with the Yokohama Advan A052 being pretty much the dominant tire. The new tier (+1.6 multiplier) features the slower 200tw models as well as the 100tw endurance tires tested here.
[200-treadwear tire test | Falken RT660 vs. Yokohama A052 vs. Nankang CR-1]
We happened to have a set of the Yokohamas worn to perfection at 3/32 inch, so we returned to the track the following day. How would they stack up against the Maxxis RC-1?
The track conditions gave us another second of improvement, and both tires delivered times in the 1:23 range–but the Yokohama was a solid four-tenths faster. The extra grip was evident in every corner, especially in combined loading coming off the turns.
As we expected from previous experience, the Yokohama’s quickest time came on lap one, but the low tread depth improved consistency: A window of just two-tenths covered all the laps. However, the Maxxis delivered more consistency, with three laps differing only by two-hundredths. And the data traces laid over each other exactly.
Now to put a value on power-to-weight changes afforded by each tire group. For our third session, we brought along our tuning laptop so we could switch the engine’s output between the detuned, 207-horsepower setting used for this test and the full, 228-horsepower setting used for previous testing. (This change in horsepower mirrors that allowed by the NASA multiplier when moving between these two tire categories for our 2200-pound, TT4-class car.)
In back-to-back sessions, we again found a four-tenths difference, but this time it was all in pure acceleration. More power or more grip: same result.
While this specific outcome only applies to this car running on this track, the testing methodology applies to any car. Moreover, it shows that NASA has done its homework in making these new rules more equitable across a wider range of tire choices.
Winners and No Losers?
With most of our tests, we have very clear winners and losers based on performance. Typically, each tire exhibits some personality traits that make it immediately identifiable from behind the wheel.
Not so this time.
All these tires are fairly interchangeable in both lap time capability and feel. Choice will come down to other factors, such as sizing, price, availability and contingency offerings: Maxxis and Toyo both have support programs for NASA, while the Nankang is the least expensive of the three.
Each tire also exhibited low wear, but at 4/32-inch molded depth, the Toyo offers 50% less available tread than the Maxxis and Nankang.
Heading to the track and not confined by today’s popular 200tw limits? Looking to take advantage of recent NASA rule changes? These three could be solid contenders.
Photography Credits: dgillenphoto.com (CRX), Andy Hollis (tires)
