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Please note that with any difference from original sizes the rolling circumference changes and the tyre clearance needs to be checked. Pay attention to the load index and adjust inflation pressure of the tyre. Follow the instructions of the vehicle manufacturer.
A tyre which can achieve high mileage is an asset because a longer lifespan leads to lower costs.
The mileage attained by motorcycle tyres and in particular that by the rear wheels of performance bikes cannot be measured in the same way as that of car or truck tyres. Because the motorcyles themselves weigh comparatively less they are able to accelerate faster and during this acceleration the rear tyre slips. This slipping leads to wear on the tyres.
A pillion passenger whose weight is solely placed on the rear tyre helps to prolong the life of the tyre. The rear wheel is pressed onto the road with more force, there-by reducing the amount of slipping. The tyre therefore lasts longer.
While testing motorcycles on a mileage tester, very high tyre temperatures may occur. Because of the smooth surface of the rollers the tyres slip and become hot during testing. Afterwards the tread is often visibly destroyed. For safety reasons we recommend that after the test the tyres are not fitted, or to use for these tests worn tyres that otherwise would have been replaced.
Worn out tyres influence the handling of a motorcycle and thereby reduce the capacity for safe driving. The recommended minimum tread depth is 2mm.
Only a fitting aid. Should be twisted against the valve cap after fitting the tyre.
Where a tyre has directional arrows moulded upon it, the tyre must be fitted so that the relevant front or rear arrow follows the direction of rotation. Road handling and tyre wear may worsen, or damage to the tyre can occur in extreme circumstances if these instructions are not followed.
It is generally true that the fitting of tyres to a motorcycle should be in accordance with what is written in the vehicle papers, otherwise the licence becomes invalid. For example, if tubeless tyres are prescribed in the vehicle papers then tubeless tyres must be fitted. The same is true for tubetype tyres.
If an appropriate indication has not been given in the papers, then in the following circumstances either tubeless or tubetype tyres can be fitted.
NEWS
Dunlop, one of the world's leading
manufacturers of high and ultra high performance tyres, has launched Dunlop
Sportmax Qualifier, a new motorcycle tyre designed specifically for supersport
and hypersport motorcycles.
The Dunlop Sportmax Qualifier significantly out-performs its predecessor in the
most important areas including dry grip and manoeuvrability. These improvements
are due to the utilisation of the latest technology, combining race tyre
attributes with new compounding and construction for optimised performance in
all riding, road and weather conditions. The Qualifier also demonstrates
Dunlop's rapid response to market demands by the fact that the Sportmax GP
racing tyre was introduced to the world in February 2005 and now, just eight
months later, Dunlop is presenting its road legal equivalent in the Qualifier.
Growing segment
The road radial segment of the motorcycle tyre market, in which the Sportmax
Qualifier will compete, is rapidly growing. It currently represents more than 45
percent of the total market, having grown from 37 percent in just five years.
The Sportmax Qualifier fits into the Dunlop range between the D220ST for super
touring bikes and the D208RR and GP Racer for hypersport machines or and
supersport machines. It is aimed in particular at the supersport bike, which is
typically a 600cc – 1000cc, multi-cylinder, high performance machine. It is also
suitable for top sport touring machines and for hypersport or superbikes, where
the power to weight ratio can be as high as 1 bhp/kg. The Sportmax Qualifier has
been developed from the legendary World Championship winning D208GP tyre and
replaces the Dunlop D208 in Dunlop's motorcycle tyre range.
From race to road
As road conditions are much more varied than the track environment, the
performance requirements for a high performance road tyre are far more complex
than those of a race tyre. A road tyre needs a high level of ride quality and
rider feedback, coupled with durability and the capability to handle all road
surfaces and weather conditions. These are less important in racing where tyres
are developed to provide the ultimate performance for a specific circuit and
weather conditions.
Furthermore the riding style is totally different. During cornering, racers have
little interest in the progression of lean angles on a front tyre. In racing
conditions, the tyre will go virtually instantaneously from the vertical to the
shoulder where riders demand maximum lean grip. Road machines require light,
progressive handling with superb corner entry stability. A road rider will use
all of the intermediate lean angles expecting consistent grip irrespective of
the lean angle, and neutral steering characteristics from the vertical axis down
to the shoulder. This is just one example of how Dunlop's race tyre designs have
had to be adapted from their original form to address the requirements of a
road-going application.
Dunlop engineers focused on developing their next-generation tyres using racing
technology, applied to meet the needs of a new generation of sport bikes. These
bikes are now almost identical to their superbike and supersport counterparts.
They have higher power, less weight and improved chassis giving performance
levels higher than ever before. In order to put this in context, in eight years
some machines have seen a 60 percent increase in power to weight ratio over
their predecessors. Dunlop's tyre technology has evolved to give riders the
possibility to enjoy the complete benefits of these latest machines.
"What we set out to do was build a street tyre out of a race tyre," said Jose`
D'Alessandro, Director Motorcycle Tyres for Dunlop Europe, Middle East and
Africa. "We had the D208GP legacy to tap into as well as our innovative Sportmax
GP. Our goal was to preserve as much race tyre performance as possible while
engineering the new tyre to meet the stability, durability and wet-weather
performance levels required for the next generation of exciting bikes. In
attacking this task, our engineers brought to bear all of Dunlop's latest tyre
innovation, including new rubber compounds, new constructions, new tread
patterns and new profiles, using the latest development technology. We used FEA
(finite element analysis) to determine the optimum profiles and required
compound properties. The Qualifier is engineered to totally satisfy the needs of
the modern supersport and superbike road rider and to match the performance of
the current generation of machines", said D'Alessandro.
Newest Development Technology
The development work has been predominantly centred on three areas: 3D Rolling
Simulation Technology (FEM), Internal Drum Machine evaluation and track testing.
· 3D Rolling Simulation Technology is a complex computer software program which
allows engineers to simulate tyre running performance under all conditions. ·
The Internal Drum Machine is a test rig in which wet grip can be evaluated using
actual tyres under varying conditions of angle and load. · Track testing takes
place under controlled conditions on Dunlop test tracks around the world. From
the input of these technologies, the construction, profile and pattern of the
tyres and their treads were developed. A further vital contribution to
construction development is Dunlop's Carcass Tension Control System (CTCS) which
allows different areas of the tyre casing to be designed with different tension
levels. CTCS controls the stress distribution within the tyre and thus provides
an optimised contact patch area across the entire spectrum of lean angles. CTCS
achieves this without the use of additional components, thus reducing tyre
weight.
Tread
The Sportmax Qualifier's tread patterns are very similar to those of the
Sportmax GP, with directional groove alignments front and rear. The Qualifier
pattern contains more longitudinal elements in the centre of the tread for
enhanced wet grip, and has excellent wear resistance in dry conditions. An
extension of Dunlop's curve design strengthens pattern stiffness for better grip
and wear which also helps to eliminate stepped wear and allows the use of softer
compounds.
The curving tread pattern is designed so that pattern elements are precisely
aligned to resist the cornering, acceleration and braking forces generated at
different angles of lean.
Computer Aided Tread Engineering (CATE) is further Dunlop technology used to
optimise tread pattern stiffness, yielding improved linear handling and reduced
stepped wear and providing the possibility to use a compound with enhanced grip.
Mid-corner feedback and manoeuvrability are improved by minimizing modifications
of the contact patch with progressing lean angles. The new tread profile shapes
are designed to maintain a more consistent contact area with the road and
minimize steering geometry changes when cornering.
As the front tyre is predominant in the handling of braking and steering forces
and the rear tyre takes care of acceleration forces, the pattern directions of
the two have to be different.
The power forces on a tyre can be illustrated by three lines. On a front tyre
the forces are braking, which is parallel with the tyre's centre line and in the
direction of rotation. The lateral or steering force is at right angles to the
tyre and therefore this means that the tyre power forces lie somewhere between
the two lines. On a rear tyre, there is driving power for acceleration rather
than braking power and the two forces are in opposing directions. In other words
the tyre power forces lie at about 45o to the centre line and face forward on
the front tyre and backward on the rear tyre. Therefore the lateral tread
grooves are parallel to the tyre power force lines for optimum grip in all
conditions
Construction
Computer Aided Design (CAD) and Finite Element Analysis (FEA) led to the design
elements of the front and rear tyre constructions:
The front tyre construction features two cut angle breakers and a two ply
carcass and four tread plies (two nylon and two aramide cord reinforcing belts).
This controls the tread shape and contact patch with excellent damping which
equates to better feel from the contact patch and a more progressive steering
response.
The Jointless Band (JLB) rear tyre construction features continuously wound
aramide tread belts to ensure consistent tyre diameter in all operating
conditions. The 180/55ZR17 and 190/50ZR17 sizes utilise one nylon carcass ply
and two tread belts (one nylon and one aramide). The 200/50ZR17 has two nylon
carcass plies and three tread plies (two nylon and one aramid). Improvements in
the belt design and construction have significantly reduced weight in the
Sportmax Qualifier rear tyre by approximately 0.5 kg. This reduction in unsprung
weight has a profound influence on the reduction of the gyroscopic impact of the
tyre and rim combination. This contributes to increased acceleration and
steering performance and also improves suspension characteristics, reducing
steering effort and enhances rider feedback.
The rear tyre construction features a single aramide 0o Dunlop JLB breaker belt.
Combined with CTCS, this construction produces a tyre with improved stability,
handling, grip and comfort. It minimizes centrifugal fling of the tread centre
at high speed and maintains a stable contact patch and reduces distortion and
heat build-up.
Compound and Profile
Finite Element Analysis was also used to determine the optimum profiles and the
required properties for the compounds. The rear tyre tread formulation is very
similar to the medium traction compound employed in the new Sportmax GP race
tyre. The front tyre profile is the conclusion of close co-operation with
Dunlop's Motorsport Development Centre in the United Kingdom. The front profile
maintains the aspect ratio of the Sportmax GP, whilst its compound is inspired
by that of the D208GP tyre. The more triangular profile of the front tyre
favours quicker turn-in and lighter steering, and also contributes to a larger
footprint at maximum lean angles.
The compound is a blend of three tailor made polymers reinforced with a fine
particle size, high structure carbon black and extended by the use of a
proprietary resin. The utilisation of these key Motorsport materials ensures
high grip in all road and weather conditions without sacrificing tread wear due
to optimised bonding between the high surface area black filler and the
chemically modified polymers.
Compound and profile selection for the Qualifier went hand in hand with tread
pattern development. The new compounds made it possible to significantly
increase the amount of land area in the tread pattern while giving excellent wet
weather performance. The benefit is the higher surface area of the front and
rear footprints, thus increasing the grip of both tyres and ensuring a balanced
ride.
Increased Performance
The Qualifier has improved side grip and better drive traction out of corners,
allowing higher cornering speeds and quicker exits.
On the front, the Qualifier requires less steering effort, which means that
directional changes like turn-in and transitions occur more quickly. The
Qualifier has greater adhesion and the tread compound heats up more quickly – a
benefit for street riding. The Qualifier has a higher level of performance and
predictable, confidence inspiring handling.
The Sportmax Qualifier performs excellent In the areas of dry grip, turn in,
manoeuvrability, tracking position and steering effort. In addition the Dunlop
engineers could improve the tyre's braking efficiency significantly.
