|
Pirelli Scorpion
ATR Tire Test
 It
used to be that if you wanted to use your vehicle off-road, you paid a
price: tires that could handle rough or muddy terrain were engineered
specifically to do so, and while they'd get you easily through the bush,
they were another matter once you got back on the asphalt. The price you
paid for off-road performance was a highway ride that was rough, bouncy and
very noisy.
Today's trucks and SUVs have an almost seamless ability to go from on- to
off-road - in many cases, with a transfer case that engages at the touch of
a button - but their tires need to be able to adapt as well. Even if most
drivers never go further off-road than missing the driveway and running over
the lawn, tire manufacturers have to keep up with the trend.
To that end, I was invited to Las Vegas for the launch of Pirelli's new
Scorpion ATR. This new tire will eventually replace the existing Scorpion
A/T, which will be phased out entirely once the ATR is up to its full range.
Pirelli claims the new Scorpion ATR is equally "at home" both on and off the
asphalt, and so we went out to the desert to see.
April can be pretty dreary here in Ontario, and after a long winter, this
heat-seeker was looking forward to a couple of days in a nice, dry desert.
But a freak weather system brought the temperature down to 4 degrees C - one
degree colder than at home! - and dropped hail and sleet on the test track.
It wasn't very pleasant when we were having lunch in an unheated tent,
but for assessing the product, it was perfect. Almost any tire can work well
under perfect conditions; it's the foul-weather stuff that "makes or breaks"
a tire.
Taking the tires through desert outside of Las Vegas. Click image to
enlarge
 Several
SUVs with various sizes and profiles of tires were used; here, a Nissan
Pathfinder takes to the trail. Click image to enlarge
An Escalade with low-profile ATRs in the Valley of Fire.
We started at the Las Vegas Motor Speedway, where two long lines of SUVs
were waiting, all clad in various sizes and profiles of the Scorpion ATR.
The tire is available in sizes from 15- to 24-inch, and in P passenger or LT
light truck versions; sidewall choices are raised black or raised white
outline letters. I chose a Nissan Pathfinder, and headed for the highway to
Nevada's Valley of Fire State Park.
Because most SUVs remain on the asphalt, noise was a primary
consideration for the ATR. The designers incorporated "sweeping curved"
grooves, while the sipes (the fine cuts in the tread blocks) are arranged in
a harmonic pattern to absorb noise created by contact with the asphalt.
They certainly did a good job; I found the ATR to be as quiet as most
passenger car tires. (My passengers thought so as well; they were tire
dealers, brought in from several states for the event, and these guys
certainly know their rubber.) My vehicle's tires were new, but Pirelli
claims that the ATR will maintain its all-terrain qualities and still remain
quiet when the tire is partly worn.
Once we reached the outskirts of the Valley of Fire, it was time to
abandon the blacktop. There are several trails cut across the foothills, and
we made our way along one of the rougher ones. The ATR took it on with no
problems, but I wasn't surprised; any vehicle, on any tire, can take on a
gravel road.
It was when we returned to the Speedway that Pirelli convinced me. An
off-road dirt track had been constructed, with the usual ditches, hills and
climbs, but the day's precipitation had taken its toll, and the surface was
wet, with some goopy areas in the low spots.
For this exercise I chose a Hummer H3, and set out with an instructor and
two passengers. The H3 crawled obediently in and out of the trenches, and
maintained its grip when teetering sideways with two wheels on an
embankment.
But the most compelling test was when I crested a steep hill; on
the descent, with the Hummer's nose pointing at the ground, the instructor
had me apply the brakes and just sit there for thirty seconds on the wet
dirt. Although the H3 weighs 2,132 kg (4,700 lbs) even before you put four
adults into it, it never moved or slid.
From the SUVs, we moved over to a nearby asphalt track, where four
vehicles were waiting: two BMW 3 Series and two Minis. All had Pirelli's
Eufori@ (yes, I know, but the company says it reflects "technology";
pronounce it like the correct "euphoria") run-flat tires, but on two
vehicles, one tire was missing a valve stem and was completely drained of
air.
Pirelli mounted Eufori@ run-flats on four vehicles, and on two, removed
the valve stems from one tire. Here, a 3 Series tackles the test track.
Click image to enlarge
Run-flat tires, also known as "extended mobility" or "run-on-flat" tires,
use reinforced sidewalls and temperature-resistant rubber compounds that
help to maintain integrity when low or deflated.
Pirelli says its Eufori@ will do this for up to 150 km, at speeds up to
80 km/h. There are several benefits, including better control when a tire
deflates (a conventional tire will often come right off the rim) and
enhanced safety (both in and out of the vehicle; you're not on the side of
the highway changing a tire).
As well, automakers can utilize the space normally occupied by a spare
tire for extra cargo room, and there is a weight savings when an extra tire
and rim are eliminated.
On the down side, run-flats are more expensive than conventional tires,
and require special rims and tire pressure monitoring systems (TPMS), since
they don't look any different when they deflate and the driver must be
informed of air loss via a dash-mounted warning.
Because of these factors, they're almost exclusively sold as replacements
for original equipment, rather than drivers swapping them for conventional
tires, but when TPMS becomes mandatory on all vehicles in the 2007 model
year, expect to see tire manufacturers emphasizing the safety factor as they
try to get drivers to switch.
Currently, they're mostly found on premium vehicles; BMW now uses them on
all 3 Series models (except for the M3) and on some 5 Series models, and
expects to broaden the range in future generations of the 7 Series, X3 and
X5.
Our task was to take the vehicles through hard acceleration, panic stops,
sharp turns and slaloms, and figure out which tire was flat. There were no
visual clues: all four looked equally inflated. I was expecting some
deterioration in handling, especially since I tossed the cars quite hard
into the curves, but there was none.
Only on hard braking, when the steering wheel moved slightly to the
right, was I able to confidently determine which tire was faulty.
Because of their beefed-up construction, run-flats are notorious for
giving a much firmer ride than conventional tires; a Pirelli spokesman said
the Eufori@ gives a comfortable ride, and in future I'm going to try to
score a vehicle so equipped and give it a shakedown on the street, since our
short track test didn't really give much time to focus on that aspect.
An Expedition at the lookout point. The Scorpion ATR is original
equipment on some Ford vehicles.
 It's
easy to say nice things about a product when you're the company's guest, but
I'm not falling into that trap; the Scorpion ATR and Eufori@ impressed on
their own merits.
Most SUV owners will never drive anywhere other than the street, and so
the ATR's off-road ruggedness may be lost on them, but its ability to hold a
heavy vehicle on a muddy hill should translate well into sure-footedness in
nasty weather (the Scorpion ATR is offered as original equipment on a few
vehicles, including the Ford F-150).
And while tires overall have improved in quality, with blow-outs now much
rarer than they used to be, the Eufori@'s ability to maintain control even
in extreme conditions should give drivers extra peace of mind.
Pirelli's advertising campaigns have gone high-tech, too; the company has
commissioned a series of short films, starring such actors as John Malkovich
and Naomi Campbell. These can be viewed on the Internet through
www.pirelli.com, or directly at www.pirellifilm.com.
See which
Pirelli tires will fit your vehicle
See Ratings
Of 495 Tire Styles
click
here
|
