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It’s on the private test circuit located in Mireval,
near Montpellier, which Dunlop presented at the start
of the week its new dual compound tire. Called RoadSmart,
it will replace the Sportmax D220 ST from next week. Invited
in this test, the Repaire des Motards was able to judge on the spot of this
new tire.
The RoadSmart is a "Sport-Touring" type tire intended for
to a wide range of motorcycles ranging from sporty roadsters to big ones
GT, some users of which are looking for tires with a good
grip in dry and wet, a good feeling, all
with good longevity. The market in question
has increased by 5% per year for 5 years, enough to fully justify the efforts
manufacturers in this segment. A growing number of users
is aware of the fact that Sport-tourism tires,
longer life than typical sport tires,
have performance that amply meets
their expectations in the context of their use. Technologies
have made immense progress, and modern Sport-Touring tires
offer as much grip as the tires fitted with the original equipment
the sportswomen of a few generations ago. Other reason
explaining the growth of this market: some motorcycles like the ER-5
or the CB500 formerly equipped with fairly durable tires
but not radial, have been replaced by models
fitted with sport-touring radial tires.
The Dunlop RoadSmart competitors are:
- Michelin Pilot Road 2
- Pirelli Diablo Strada
- Bridgestone BT-021
- Metzeler Roadtec Z6
- Continental Conti RoadAttack
With the exception of the Bridgestone, all of these tires incorporate the word "Road"
(road) in their name, Strada meaning road in Italian.
Here is what allows to identify them well.
Before going into more details on the characteristics
of the new Dunlop RoadSmart, first let’s do a little reminder on
dual-compound technology more and more used by manufacturers.
As many of you will have noticed, the tires fitted
on the back of motorcycles often tend to wear out
faster in the center than on the sides. The phenomenon
is emphasized on motorcycles with a large displacement engine
and torquey and by long motorway journeys. Of course exceptions
exist since the use that is made of the tire has a great impact
on its wear. So if the tire is used as part of a
very sustained use and on winding roads, the tire will be worn
uniformly over its entire surface. But it still remains
that the vast majority of users reach
the wear indicators located in the center of the rear tire,
even though there is still a good thickness of rubber on the
sides. Dunlop has thus determined that on average
a rear tire remains in contact with the road 90% of the time when
level of its central zone.
Taking into account this non-uniform wear of their motorcycle products, the
manufacturers use dual-compound technology based on
the use of two gums of different hardness on
the same tire. Thus, the place where the wear is the strongest,
the center of the tire is therefore coated with a harder rubber than on
the "sides" of the tire, called shoulder strips.
The primary goal of dual compound technology is to increase longevity
of the tire and not to offer an even better grip. It is so for
all dual-compound tires, whether they are tires intended for individuals
or tires used in MotoGP.
Like all new Dunlop tires marketed this year,
the RoadSmart is a dual compound, the structure of which is clearly visible
in the illustration below:
In yellow, we see the "hard" eraser, located on the strip
central tire. On the sides shown
in gray in the diagram, the tire is coated with a rubber more
tend only in the center. As can be seen, the central hard gum
extends under the side shoulder bands. this
allows heat to escape more efficiently when
the tire is used in a straight line at a steady pace or
fully loaded.
In the case of the RoadSmart, Dunlop chose not to equip the
dual compound technology front tire. This is a decision
surprising given the presence on the market
of the Michelin Pilot Road 2 equipped with dual-compound techno
the back as in the front. Dunlop explains his choice by
its desire not to compromise on the grip of the front tire.
Thus, it is soft gum that is placed over the entire
of the front tire, a rubber identical to the one on the
rear tire sides.
In order to be able to try out its new tire, the manufacturer has
the disposal of testers the tracks of its test center in Mireval.
This one, acquired in the 80s by Goodyear, is established
on an arid and rocky domain of 200 hectares. The center has
several tracks, visible on this aerial view:
The largest circuit, referred to as "HPC" for "High
Performances Circuit "(High Performance Circuit) is
3.3 km. It is possible to expect the 250km / h and the SERT, French team
endurance, has already come to do his tests. Inside
of this large circuit is the "rain" track with a length of
1.7 km. It is watered constantly and products are added
to the spilled water in order to avoid the proliferation
seaweed. On the right of the aerial view, there is a ring
of 100 meters of radius allowing to judge the stability
curves and also to simulate their wear. We will also note the
presence of other test facilities, including two straight lines
located in the center of the complex and an all-terrain track.
In addition to motorcycles fitted with the new Dunlop tire for
tests, it is with astonishment that we discovered the
provision of machines equipped with tires
competitors, namely Bridgestone BT-021 and Michelin Pilot
Road 2. It is indeed rare for manufacturers to provide
competing tires during testing. This denotes a real
Dunlop’s confidence in its new product. Were the tests going
justify this trust ?
The tests begin with a riding session on the ring,
performed at constant speeds (50km / h then 90km / h)
on Honda VFR 800. They demonstrated the good stability
and guidance precision provided by RoadSmart. The motorbike
is easily guided and stays on course without having to
correct the trajectory. A quality also present on
the Bridgestone BT-021. The Michelin Pilot Road 2 is a little worse on
this point, its steeper profile, although it offers a greater
liveliness, tends to pull the motorcycle inward
of the curve hence the need to correct more often
path.
On dry track and mounted on a GSXR-750, the RoadSmart
behaves very well there too, cashing correctly
the power of the motorcycle, even if this sport-touring tire is
not really intended to be mounted on such
vehicle. The grip is really very good, and the bet on
the angle is very reassuring. Competitors, whether the BT-021
and the Pilot Road 2, also behave very well on this point.
Tests continue on the wet track with equipped Z750s
of ABS. The RoadSmart is doing well. The plus profile
round of the RoadSmart compared to the Pilot Road 2 gives more confidence.
The Bridgestone offers on this point a progressiveness similar to the
Dunlop but its grip in the wet is in decline compared
to competitors. On the corner, the Dunlop stalls so
very considerate of the rear which is a quality
very appreciable. Remember that the grip of Sport-Touring tires
in the wet and whatever the brand, is not extraordinary.
These are not extra soft gums and caution
must remain in place. But the RoadSmart offers enough grip to
tackle the vagaries of the weather without a cold sweat.
A road test, carried out partly on wet asphalt
and partly on dry asphalt, also allowed to verify
the good qualities of RoadSmart. Its adhesion is good
and the feeling very good. What’s more, the level of comfort provided
by the tire is excellent.
The longevity of the Dunlop RoadSmart remains however for the
moment an unknown, since this characteristic cannot be
judged on a test carried out in a few hundred
kilometers. Long-term trials we will say more, but
Dunlop is already advancing an increased lifespan
by 5% compared to the 220ST, and doubled compared to that
Dunlop Qualifier coated with a softer rubber. Attempts
led by the manufacturer on mixed courses and on Honda handlebars
VFR800, Yamaha FJR and Suzuki SV1000 thus indicate a duration of
life of around 8,000 to 10,000 km for the RoadSmart.
In conclusion the new Dunlop RoadSmart is a very homogeneous tire
and reassuring, both in the dry and the wet, filling
very well its objectives. Here is an interesting alternative
Bridgestone BT-021, with a somewhat reassuring grip in the wet, and
Michelin Pilot Road 2, tire with certain qualities
but whose steeper profile reassures a little less when putting on
angle.
Dunlop is marketing this dual compound tire at the right time, hoping
take advantage of the current consumer craze for this type of product.
The RoadSmart will appear next week among
resellers in the following sizes:
|
Before : 110 / 70ZR17 M / C (54W) TL |
Back : 150 / 70ZR17 M / C (69W) TL |
The tire will also be available for trails in the following sizes
from April / May 2008:
Front: 110 / 80R19 M / C 59V TL
Rear: 150 / 70R17 M / C 69V TL
The recommended retail price for the best-selling sizes are
The following :
120 / 70ZR17 M / C (58W) TL: 120 euros
180 / 55ZR17 M / C (73W) TL: 159 euros
| Strong points | Weak points |
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