Rain can catch us off guard, but we can’t use a few puddles as an excuse for poor performance. We have to press on, and that requires an exemplary set of appropriate tires.
There are plenty of tires that work well in the dry—we’ve been testing them for the better part of three decades—but there aren’t nearly as many designed for wet-weather performance. Whether the venue is an autocross, road race or track day, the proper wet-weather tires can be critical.
Some of our usual front runners will certainly get you home in the damp, but they aren’t designed to go splashing through puddles with abandon. Their large tread blocks and lack of significant siping will keep them from properly adhering to a wet road. Making matters worse, the chemical makeup of the rubber on such tires is rarely ideal in rainy conditions.
So, if you have the means and desire, what tires do you mount when things start to get wet? To get some answers, we first asked the professional tire jockeys at Tire Rack to narrow down the field to a more manageable number.
The Tire Rack test circuit has a full sprinkler system that allows for wet testing even when the sun is shining.
After reviewing their input, we picked three grippy street tires that had a good chance of also being respectable in the wet. The Dunlop Direzza Sport Z1 Star Spec is the tire of choice for our MX-5 project and has proven capable in both the wet and the dry. We used it as our baseline tire and pitted it against the Toyo Proxes R1R and the Continental ExtremeContact DW; both have garnered positive enthusiast reviews.
We also threw one wild card into the mix, Continental’s ExtremeContact Wet. This true racing rain tire is used in Grand-Am’s Continental Tire Sports Car Challenge.
John Rogers of the Tire Rack and Tech Editor Per Schroeder (not pictured) handled the driving and testing duties.
For a test vehicle, we pressed our 2010 Mazda MX-5 project car into service. It’s been worked over to meet the letter of the law in SCCA’s new Street Touring R category. As detailed elsewhere in this issue, the car features larger anti-roll bars, a K&W coil-over suspension, and a meaty wheel-and-tire package. The car normally rolls on trash can-sized 17x9-inch wheels fitted with 255/40R17 tires.
Those fat tires don’t work all that well in rain, however, so we elected to compare a smaller size—something more appropriate for the damp conditions. The test size was a 225/45R17, and we mounted all of the tires on identical 17x8-inch wheels.
Eagle-eyed readers will note that our wheels look a little familiar: They’re actually Ford Mustang Bullitt wheels. They feature a compatible 5x114.3mm bolt pattern and appropriate offset.
Our two drivers, Per Schroeder and John Rogers, each completed four laps of the Tire Rack test course for each tire tested. The track incorporates a slalom and a large skidpad, and the surface was fully dampened by a platoon of sprinklers that ran during the entire testing procedure.
Once armed with data, we determined best as well as average lap times. Averaging the data would help cancel out any missteps and remove some of the effects of learning a tire’s steering responsiveness.
Dunlop Direzza Sport Z1 Star Spec
price: $135 each
weight: 25.2 lbs.
average lap: 31.18 sec.
best lap: 30.78 sec.
The Dunlop Direzza Z1 Star Spec is a solid all-around tire with great skidpad grip in the dry. In the wet, it exhibited the same moderate steering response coupled with stable vehicle balance. It was easy to induce a little mid-corner understeer if we pushed too hard.
Unfortunately, when we asked for a little reserve grip, we didn’t get as much as we desired. As we reached the Dunlop’s wet adhesion limit, the overall grip didn’t plummet with large slip angles; it did, however, take a moment to recover after stepping off the relatively narrow peak. Under braking, the Mazda’s ABS engaged every once in a while—especially when we asked for a little more after the initial pedal application.
The safe and solid nature of the Star Spec makes it a great option for a daily driver that sees track and autocross use. We’ve mounted them on several of our project cars for this very reason.
Toyo Proxes R1R
Toyo Proxes R1R
price: $185 each
weight: 23.8 lbs.
average lap: 30.54 sec.
best lap: 29.91 sec.
The Toyo Proxes R1R is one of the top dogs in the Street Touring tire wars. It’s got the soft compounding and symmetrical pattern of a wet race tire yet performs like a dry tire when the tread depth is shaved down to 3/32 inch.
The Toyo exhibited much faster steering response and greater front-end authority than the Dunlop. That second trait, however, easily overpowered the traction at the rear of the car, leading us to our first spin of the day. We had to modify our hand speed to keep the back end of the car from coming around too quickly on corner entry. We also needed to manage the throttle when accelerating off tight corners or around fast sweepers.
Overall grip felt noticeably stronger than with the Dunlop, and straight-line braking was very good. While the Toyo is a fast tire, it required a lot of mental effort to manage.
Our takeaway impression: This would be a great tire for a front-wheel-drive application. The steering response would really help the inherently pushy front-driver get around the cones. That said, it was a full half-second faster than the Dunlop and felt great.
Continental ExtremeContact DW
Continental ExtremeContact DW
price: $131 each
weight: 20.6 lbs.
average lap: 29.39 sec.
best lap: 28.68 sec.
From the first turn of the wheel on the Continental ExtremeContact DWs, our drivers knew this tire was in a league of its own among our test subjects. It simply carved through the corners as though they were dry.
It had better steering authority than the Dunlop without the edgy, nervous feel of the Toyo. It’s a more-than-competent dry-performance tire, but its wide grooving took care of puddles with ease.
The ExtremeContact DW’s front-to-rear balance was excellent, providing very good overall grip in the skidpad. Braking was surefooted coming into the slower sections, with little in the way of ABS engagement. Coming out of corners, the acceleration traction was also very good compared to our previous runs.
It was easy to drive quickly on the ExtremeContact DWs, and we didn’t exert much mental effort to put in quick lap times. It was by far the easiest and subjectively fastest tire of the test.
Continental ExtremeContact Wet
Continental ExtremeContact Wet
Price: $245 each
weight: 21.1 lbs.
average lap: 28.36 sec.
best lap: 27.82 sec.
The Continental ExtremeContact Wet is a true racing tire that was hardly challenged by water on the track. While the steering was not quite as responsive as with the street Continental, the overall grip level was excellent.
Unlike the other tires, full-throttle application through the slalom did not appreciably wag the Mazda’s tail. There was very little wheelspin when coming out of any of the corners, as our drivers could circle the skidpad faster than ever. In the fast sweeper, both drivers were constantly hitting the rev limiter at the top of second gear, all without any yaw-inducing wheelspin.
After eight laps, however, the tire seemed to slightly break away in some areas of the skidpad—particularly at the 12 o’clock position, where the water puddled a little. Despite that one minor blemish, the tire still felt just as balanced and consistent as it did during the first five laps.
The Continental ExtremeContact Wet tire took some effort to drive fast, mainly because some time was needed to readjust to the higher speeds. It begged a simple question: Is the track even really wet?
If there’s a downside to this tire, it’s the availability. It’s not legal for street use since it hasn’t garnered the DOT stamp of approval. Plus, as the spec tire for the Continental Tire Sports Car Challenge, it’s only available at the track prior to their events. Even so, it provides a great benchmark for the rest of our test subjects.
Dunlop Direzza Sport Z1 Star Spec (Retest)
average lap: 30.99 sec.
best lap: 30.61 sec.
As usual, we retested our first tire just to make sure that our conditions had remained consistent throughout the test. All of the average and fast laps were about two-tenths ahead of the first go-around, and we considered that to be an insignificant change. We’d say our data looks good.
The second runs on the Dunlop also felt similar to our first sampling, exhibiting some sluggishness. Also, if entry speed was not just right, the Dunlop seemed to first lose grip at the front, transitioning to gentle understeer as the apex approached.
The Right Tool for the Job
There are fast and slow tires for dry, high-traction conditions. Likewise, the wet surface of our test track highlighted some differences among our test subjects. All three street tires exhibit exemplary manners on the road—rain or shine—but pushing them to the limit at the Tire Rack track revealed some interesting data.
Final verdict? The Continental ExtremeContact DW is our street tire choice for wet conditions. Of course, it’s no match for the purpose-built racing rain tires, but it would certainly get the job done for a street car.
Sources
Continental Race Tires: continentaltire.com, (800) 847-3349
Dunlop: dunloptires.com, (800) 321-2136
Hoosier Racing Tire: hoosiertire.com, (574) 784-3152
Tire Rack: tirerack.com, (888) 981-3952
Toyo Tires: toyotires.com
