On the wet and dry course
On the wet and dry course. Click image to enlarge

Story and photos by Jil McIntosh

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Driving Dunlop

Las Vegas, Nevada – When Bugsy Siegel stood out here in the desert and envisioned a gambling empire, cars ran on tubed bias-ply tires that didn’t take well to hard cornering and weren’t too keen on high temperatures.

But that was then, and now, under a cloudless sky and in 30C temperatures, it’s time for me to put Dunlop’s newest generation of high-performance tires through their paces.

The event was tied in with SEMA, the Specialty Equipment Market Association’s giant trade show, where Dunlop had a display booth (complete with an appearance by tattoo artist Kat Von D, along with an opportunity for show-goers to be inked with tire treads or Dunlop logos), but the only way to understand a tire, of course, is to drive on it.

Dunlop SP Sport Signature
Dunlop SP Sport Signature. Click image to enlarge

To that end, a group of journalists and tire dealers went to the Las Vegas Motor Speedway, where we drove the Direzza Sport Z1, SP Sport Maxx GT and SP Sport Signature, as well as a quick go-around with the SP Sport 9000, fitted to an odd little duck called the GG Quad. The tires are all part of Dunlop’s high-performance product line-up.

The day consisted of three exercises: a dry autocross, with Subaru Impreza WRX models clad with Direzza Sport Z1 tires; a dry/wet course, in BMW 328i models with SP Sport Signature tires; and track testing with BMW M5 models on Sport Maxx GT tires.

The Direzza Sport Z1 – which is pronounced “zed”, even in the U.S. – is an extreme summer performance tire. Made in Japan, it’s aimed at hard-core enthusiasts who take their vehicles to the track, and is rapidly becoming popular with professional drifters; it’s approved by the SCCA, but is also DOT-approved for street use, and comes in twenty sizes, with rim diameters from 15 to 18 inches.

Subaru Impreza on the course
Subaru Impreza on the course. Click image to enlarge

The technical stuff is that its large shoulder blocks improve grip, its “brake slots” hold better under hard stopping, and while it’s intended primarily for dry-asphalt contact, it has dual centre channels intended to push water out and keep as much rubber on the road as possible should the weather turn nasty. The rubber-on-road feel, when tossing the Subaru around the course, is that the Direzza is extremely sticky, allowing me to spin the car confidently around some very tight corners. Despite the grip, the Direzza is surprisingly quiet for a performance tire.

That’s all relative, of course, and as a comparison, Dunlop had some Subaru models shod with Bridgestone Potenza RE-01 tires. Such exercises are always in favour of the presenting company, of course, but driving the two brands back-to-back, there was a definite difference: the Bridgestone tires tended to drift out more in hard corners, and the car’s back end stayed steadier with the Dunlop tires. The best way to describe it is that if I hadn’t known which was which, I would have suspected both cars to be shod with Dunlop, but with one brand-new set and the other with about 30,000 km on them. (In reality, both were identical fresh sets, out on the track for the first time, and with identical air pressure, according to officials at the event.)

The Direzza also features “Max Flange Shield”, a thin rubber strip above the wheel flange; scrub a curb, and the tire takes the hit, rather than your expensive alloy wheels.

Sport Maxx GT
BMW M5 on the speedway infield track
Sport Maxx GT (top); BMW M5 on the speedway infield track. Click image to enlarge

Next it was off to the track course, located inside the Speedway’s main oval, where a fleet of BMW M5s were waiting. The Sport Maxx GT, already available in Europe, is expected to go on sale in North America in 2008. It will come in eight sizes at first, to fit cars such as the Lamborghini Gallardo, Porsche 911 Carrera S, Audi S5, BMW M5 and M6 and the Jaguar S-Type; additional sizes will follow, in rim diameters from 18 to 23 inches.

Made in Europe, the Sport Maxx GT builds on Dunlop’s existing SP Sport Maxx line-up, and is a premium maximum performance tire intended strictly for summer use. It has a slightly lower tread depth than the Sport Maxx, to put more rubber in constant contact with the road surface, and has a sidewall insert to reduce flex when cornering. The asymmetrical tread allows for rotation on cars with staggered wheel sizes: you can’t put them front to back, of course, but they can be switched side-to-side.

As with the Direzza, grip is substantial, and even numerous higher-speed laps in the desert heat didn’t seem to affect the tires: they’re extremely stable, with no sidewall “rolling over” on hard corners. There’s plenty of feedback from them, but at the same time, the ride is surprisingly smooth. That will come as good news to drivers who want to be able to push their cars to their maximum potential, but still be comfortable enough for regular street use.

GG Quad with Dunlop SP Sport 9000 tires
GG Quad with Dunlop SP Sport 9000 tires. Click image to enlarge

With the Sport Maxx under our belts, it was back onto the bus to the next part of the course, but this time around, we detoured for a look at the new GG Quad, which was being introduced at SEMA. Built in Switzerland, the 363-kg four-wheeler uses a 90-hp BMW engine and has a top speed of 193 km/h, although of course you can get faster models if you don’t mind spending more money. It uses motorcycle controls, and my inexperience with that particular mode of transport didn’t help my poor performance around the track, although I wasn’t the only one: some journalists much more familiar with both motorcycles and ATVs criticized the GG Quad’s steering, which even its representatives reluctantly admitted could use some fine-tuning. They’re apparently street-legal in the U.S., but with a starting price of US$49,500, it may be a while before you actually share the road with any.

Having become intimate with a few road cones on the GG Quad, it was good to be back with easily-steerable wheels, this time on the wet/dry course in the BMW 328i, on Sport Signature tires. While the U.S.-made Signature has been a Dunlop mainstay for many years, the company was introducing seven new sizes, with a new 20-inch version on its way.

Wet and dry course
Wet and dry course. Click image to enlarge

The Sport Signature is an all-season tire, and obviously I didn’t get a chance to try this one out in snow on the track. But our course was liberally soaked (a constant task for the water truck, since liquid evaporates almost immediately in the desert) and we had to take the BMWs through a series of slaloms, straightaways and curves that were alternately dry and wet.

Of all the tire tests I did that day, the Signature test impressed me the most, because it was the most surprising. I expected the Direzza and Sport Maxx GT to perform as they did; any surprise would have been if they didn’t. But I wasn’t expecting a tire to move as seamlessly between wet and dry as the Signature did. There was almost no perceptible change between the two surfaces, even during panic and threshold braking; the slalom also presented no challenge regardless of the road conditions.

Acura TL on Sport Signature tires in the desert
Acura TL on Sport Signature tires in the desert. Click image to enlarge

This was the tire I drove the next day, as I took an Acura TL along a route that took us out of Vegas and to the Mount Charleston area. We were warned that there might be snow at the higher altitudes – and as much as I hate the white stuff, it would have been a good test – but temperatures were balmy, and the winding mountain roads were dry. The Signature proved quiet and comfortable, and while I still prefer to switch to dedicated winter rubber for cold weather, I was very impressed with the tire’s performance on the variety of roads on the trip up into the mountains.

Vegas might be all about gambling, but one’s choice of tires should never be a “crapshoot”.

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