No, it’s not legal for SCCA competition.
Yes, it’s still fast.
After watching many other competitors jump into today’s market for streetable track tires–most of which fall under the 200tw heading–Hoosier finally has an offering with its new TrackAttack Pro.
While it carries that ever-popular 200tw rating, it still doesn’t meet the current SCCA regulations. How’s that? This tire’s 5/32-inch tread depth …
Tire Specs
Bridgestone Potenza RE-71RS
- Fast lap: 1:24.86
- Average lap: 1:25.35
This is a fantastic do-it-all tire–the Swiss Army knife of the Super 200 category. It’s a popular choice for One Lap of America, too.
On the Road: It’s grippy in both the wet and the dry while durable enough to last for a week’s worth of daily track events. While not particularly noisy for a 200tw tire, it did convey road irregularities more harshly than other Super 200s.
On the Track: It also turned on quickly–it just needs to go through a couple of corners–which suits both autocrossers and time attack competitors. This tire displayed a sharp steering response and ran at smaller slip angles, giving it a fairly direct feel with cornering loads building in linear fashion.
The Bridgestone RE-71RS was especially good at combined loading events, trail braking easily and putting down power early on corner exit. Breakaway was progressive with clear audible feedback. However, the tire began to heat soak fairly quickly on this warm day, gradually losing grip and complaining loudly.
Goodyear F1 Supercar 3R
- Fast lap: 1:24.77
- Average lap: 1:24.96
We love this tire. It’s been our favorite streetable track tire for quite some time. Apparently that’s true for many folks like us, because they’re on back order quite often in popular sizes.
On the Road: Belying its OE design roots, the Goodyear F1 Supercar 3R
rode quite well on the highway: relatively quiet and quite reasonable over bumps. Steering response was intuitive and quick.
On the Track: That quick response was magnified as g-loads increased, with the tire willing us to go deeper and turn harder. But the limit was a bit vague, so it took some finesse to predict just how much was there. Fortunately, the plateau was wide, and overdriving has minimal penalty except for time lost.
Even on this warm day, it took the full out lap for the compound to turn on. Once it did, though, it stayed consistent throughout the session. Lap times varied by only three-tenths, with most of that coming from the vague breakaway limit.
Hoosier TrackAttack Pro
- Fast lap: 1:24.72
- Average lap: 1:24.92
This new tire is the reason for this test. Does Hoosier have a contender for those tracking today’s high-performance machines?
On the Road: The TrackAttack Pro clearly means business with its very stiff carcass. For cars with factory suspensions, this gives a noticeable boost in response–as if the spring rates had been increased by 20%. For our Triple Threat ND, though, where ride quality is already borderline from our aftermarket suspension, that boost was just enough to throw it over the edge. We felt every bump and irregularity on our drive. Every … single … one.
The tread pattern itself was very quiet without a hint of drone or buzz on smooth asphalt, but that stiff carcass amplified noisy pavement–think chip seal or irregular concrete. Steering response felt quite linear and highly responsive, but there was a small dead zone on center mitigating any need for constant corrections.
On the Track: The Hoosier was a monster. After a hard push on the out lap, full grip was available and quite high. Steering response was crisp and combined loading excellent. This was especially noticeable under heavy trail braking where the car would carve down to the apex like a scalpel despite the huge energy generated in the front tires.
Like the Goodyear F1 Supercar 3R, consistency was a strong trait with no pace drop-off across the entire session. Breakaway at the limit was more obvious than with the Goodyear.
Bridgestone Potenza RE-71RS (retest)
- Fast lap: 1:26.11
- Average lap: 1:26.34
With great data in hand, all that remained was to rerun the Bridgestones to verify that condition changes had not influenced our results.
Wait, what’s this? Even after an hour’s cooldown since the last run, the Bridgestones picked up right where they left off, achieving only slower, heat-soaked lap times. Although we kept them in the shade, the increase in both ambient temps and a sunbaked track surface conspired to keep them on simmer. Or so it seemed.
To verify our theory, we also reran the other two tires to see if we could match our earlier best times. We came very close to doing just that. Our consistency was a little off–hey, we’d been at this all morning–but we came within a few tenths for each, as opposed to being a full second off the best pace for the Bridgestone. Case closed. Time to pack it up and head home. Well, almost.
Bridgestone RE-71RS (5/32-in. tread depth)
- Fast lap: 1:24.78
- Average lap: 1:25.01
Thanks to previous long-term testing on motorsports-oriented street rubber, we know that most tires benefit from lower tread depths, either via shaving or wear. This helps with both pace and consistency.
The taller the tread blocks, the more they will bend over under load–it’s simple leverage. But that bending–the tire guys call it squirm–creates heat. And past a certain point, heat is the enemy of grip.
To some degree, this can be mitigated by having less void area in the tire, but that works against its suitability for street use, especially in the wet. So the obvious solution is shallower voids so the tread blocks are better supported. The tire will still suffer from hydroplaning in deep water at high speeds, but at least it will be serviceable in the wet if you slow down.
Like most Super 200 Extreme Performance Summer tires, the Bridgestone RE-71RS comes molded to a depth of 7/32 inch. Both of our streetable track day-category tires tested here, the Goodyear F1 Supercar 3R and Hoosier TrackAttack Pro, come molded to only 5/32 inch. Doesn’t sound like much of a difference, but it amounts to almost a 30% reduction.
While those effects are now clearly demonstrated for both pace and consistency, there is another effect: wear. As these pictures detail, the RE-71RS suffered significant graining and tearing of the outermost surface of the center tread rib, while the Supercar 3R and TrackAttack Pro showed minimal effects. Also note how the previously used Bridgestone RE-71RS, which started our test day at 5/32, shows only minor surface wear. Keep in mind that these are all right-front tires, which suffer the most at Harris Hill Raceway.
Could a set of Bridgestones sporting shallower tread run faster than a full-tread set? Let’s find out.
We had a second set of RE-71RS on hand from previous tests that had been worn down to just under 5/32. These were the tires we used during the warmup session, but they also ran one additional session at the end of the official test.
Not only were these tires a bit quicker than the new, full-tread Bridgestones, but they were much more consistent across the session. Living up to its Swiss Army knife reputation, the RE-71RS can handle almost any situation if you select the proper blade.
Round 1 Results
Round 2: Let’s Do It Again in Cooler Temperatures
While looking over the data from this test, two things stuck out. First, as the temps for the day increased, lap times trended slower. Second, that single-flyer initial run from the fresh Bridgestone RE-71RS, which almost matched the other tires, seemed out of place.
Fortunately, the weather cooled a bit just a week later, so we did the whole thing again. We also reversed the order of running and used the Hoosier as our bracket tire to get more direct back-to-back comparisons. We even reran the half-tread RE-71RS, both in the warmup session and at the end.
The only downside to this second test was that the consistently cooler temps were accompanied by a strong wind, which had brought a lot of sand from a nearby construction site onto parts of the track. Not only did that take an extended period of time to clean off, but it left the clean line quite narrow, making consistency tricky.
The data from this second test showed more of what we’d been expecting: no magic flyer run for the full-tread RE-71RS, with about a 1-second gap between it and all three of the other tires, including the worn Bridgestones, now down to less than 4/32 inch of tread depth.
The only inconsistency was the increase in pace across the first couple of laps for the TimeAttack Pro as the track continued to clean up.
Round 2 Results
So, what to make of all this?
First, Hoosier has a winner in this market segment, matching one of the current benchmarks, the Goodyear Supercar 3R. The Hoosier TrackAttack Pro hits all the marks on track–pace, consistency and drivability–while retaining appropriate street manners.
Second, we’ve directly shown how tread depth affects typical 200tw tires: Less is more. Previous long-term trend stories have revealed this for both the Nankang Sportnex CR-S V2 and Falken Azenis RT660, but here’s a direct back-to-back comparison with clear-cut conclusions for the Bridgestone RE-71RS. Note that we’ve also seen this trend with the Yokohama Advan A052.
The only questions that remain for Hoosier’s new offering are its durability and long-term consistency. How long will they last? How long will they be fast? Watch this space for those answers.