Kymco MO D50 Service Manual - chap 20 (pneumatici)

20. HIGH-SPEED TIRE

20-0

20

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HIGH-SPEED TIRE (TUBELESS TIRE)

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HIGH-SPEED TIRE CONSTRUCTION & FEATURES ------------ 20- 2
HIGH-SPEED TIRE MAINTENANCE PRECAUTIONS ----------- 20- 4
HIGH-SPEED TIRE REMOVAL/INSTALLATION ---------------- 20- 5
HIGH-SPEED TIRE REPAIR------------------------------------------ 20-16

20

20. HIGH-SPEED TIRE

20-1

HIGH-SPEED TIRE CON­STRUCTION & FEATURES

CONSTRUCTION

INNER LINER

A layer of rubber (inner liner) which
replaces the inner tube is stuck to the
inside wall of the high-speed tire. The
inner liner is made of thick rubber, a
material that high-pressure air can not
pass through. The liner can not be
lengthened like other inner tubes, so
when nails are inserted into the tire,
breaks will not be enlarged because
the nails are suppressed to avoid air
leaks. When tire break occurs, the
inserted nails will spring out to make
the tire run under low pressure. It is
very dangerous because the tire
temperature will raise highly to make
tire wobble during riding. Therefore,
riders must be very careful to check
tire pressure and inserted nails before
riding at high-speed.

•Tire pressure

•Tire deformation and damage

•Tire groove depth and abnormal

wear
Tire Depth: Front : 0.8mm

Rear : 0.8mm

•Imbedded metals, stones, or other

foreign matters

The bead base where tire and rim
contact is wrapped by rubber fabrics
called tire bead in order to reinforce
its function. The fabrics is specially
adopted for the high-speed tire to
keep its air density because air can
not pass through this material. Also,
the fabrics can keep the tire from
damage when the tire falls off, and
protect tire from damage due to
friction of wheel rim while riding.

Inner Tube

Tire Bead

Tube Valve

Tube Tire

Tread

Tire Flange

Circle Boundary

Tire Shoulder

Circle Boundary

Tire Flange

Tubeless Tire

Inner Liner

Tire Bead

Tread

Tire Valve

Tire Shoulder

20. HIGH-SPEED TIRE

20-2

TIRE FLANGE BEVEL ANGEL

If the tire flange radius is smaller than the
wheel rim radius, the tire and wheel can be
locked tightly. Take the advantage of tire
bead bevel angle to enlarge tire bead so
that the tire and rim can combine with
each other precisely. Consequently, it
can prevent air leaks and tire will not fall
off the rim when tire break or low
pressure occurs.

METHOD TO IDENTIFY A HIGH­SPEED TIRE

For distinguishing a high-speed tire from a
tube-tire, the word “TUBELESS” is
stamped on the side wall of the high­speed tire. A tire without this word
cannot be used as a high-speed tire.

RIM USED FOR HIGH-SPEED TIRE

For the purpose of preventing tire from
falling off the wheel rim while driving,
there are special requirements on the size,
shape and pressure density of rim used
for high-speed tire. It is necessary to use
special rims.
Refer to the Figure shown for distinction.
Air leaks occur easily when the wheel rim
is deformed. Avoid driving on rugged road
and crashing against stones.
When replacing the high-speed tire, also
replace the valve as a set.

• When replacing the high-speed tire,

use a tire of the same specification.

＊

Rim Used for High-speed Tire

Tire flange bevel angle is
larger than rim bevel angle
Tire Shape

TUBELESS

Rim Shape

Locked

Mark of
TUBELESS

Rim Valve

20. HIGH-SPEED TIRE

20-3

RIM VALVE USED FOR HIGH­SPEED TIRE

Air-tight valve is specially designed
for rim valve of a high-speed tire.

AIR-TIGHT VALVE
A rubber of special shape is used to

cover around the valve hole. The
spring of rubber can prevent air leaks.
Install the valve from the inner side of
the rim and then pull it out through
the rim valve hole with a special tool.

HIGH-SPEED TIRE FEATURES

•Air will not release quickly when a

nail is inserted into the tire. It is the
same as the tube-tire that tire break
may occur to a high-speed tire when
nails or other objects are inserted
into it. However, when a nail is
inserted into a high-speed tire,
external rubber and internal anti-leak
rubber will grip the nail tightly to
prevent air leaks. If the nail is deeply
inserted, air will not release quickly
to avoid sudden slipping of steering
handlebar.

•EXCELLENT COOLING

PERFORMANCE
Because the high-speed tire is

tubeless, the air within the tire will
contact the rim directly. Heat
produced during driving can be
dissipated through the rim. Heat
affects the rubber greatly and if the
tire temperature is not high, the tire
service life can be prolonged .

• Use only the KYMCO

recommended air-tight valve.

＊

There is no air leak when a nail is
inserted into the tire.

20. HIGH-SPEED TIRE

20-4



PRECAUTIONS FOR HIGH SPEED
TIRE STORAGE

STORAGE METHODS

If the space within the tire bead of a
high-speed tire is narrower than the
width of its rim, it is hard to install
the tire to the rim and pump air into
the tire. Therefore, it is better to put
cardboard within the tire bead and
put tires in order.
Tires deform easily if they are piled
horizontally. Avoid doing so.
As to the reused tires, the structure
of the rim remains the same. Install
the valve cap when the tire pressure
is lowered to 1/2 of the specified
pressure.

PLACE FOR STORAGE

The place used for storage should
avoid the following conditions:

A place where produces

ozone (a place near motors
or chargers)

A place with oils or

lubricants (especially in
service working area)

A place where produces

heat (a place near stoves
or steam pipes)

Cardboard

A place with high moisture

A place with direct sunshine

20. HIGH-SPEED TIRE

20-5

HIGH-SPEED TIRE
REMOVAL/INSTALLATION

In comparison with the tube-tire, the
following points must be noticed
when removing and installing a high­speed tire.

•When removing the high-speed tire,

avoid damaging the tire bead (special
plastic seat), tire liner (internal anti­leak material) and rim flange (bead
base).

•Apply vegetable soapy water to the

contact area between the tire bead
and rim, and use a tire iron for
installation.

•It will cause tire deformation when

removing the tire forcedly as the
figure shown. Be sure to remove the
tire following the instructions given
in the manual.

•The tight joint of tire and rim can

prevent air leaks. As long as the rim
is deformed, air leaks will occur
easily. Therefore, do not remove or
install the tire forcedly. Use special
tools and rim protector for servicing.
Frequently check if there is any
deformed part and do not use tools
of poor quality.

•Rust and rubber materials on bead

base are the main cause of air leaks.
Remove them thoroughly.

•Be sure to remove and install the tire

following the procedures provided in
the manual.

• When removing or installing a

high-speed tire, do not damage
the axle bearing. Draw or pull the
rubber on the rim lower part.

• It is difficult to remove a tire

when the rim valve is pressed by
tire flange. In this situation, do
not remove it forcedly because
the rim valve hole will be
damaged.

＊

20. HIGH-SPEED TIRE

20-6

TOOLS & PARTS REQUIRED
FOR SERVICING

Tire iron
Wheel rim protector
Knife
Water pan and probe
Vegetable soapy water
Pressure gauge
Valve core assembly tool
Valve assembly tool

Rim valve used for high-

speed tire

Valve core

11 High-speed tire

High-speed tire
Model: KYMCO DINK50
Tire size: 110/70-12 (Front)
130/70-12 (Rear)

Make sure to use KYMCO­recommend high-speed tire and
rim valve.

20. HIGH-SPEED TIRE

20-7

REMOVAL METHODS

 Use the valve core assembly

tool to take the valve core out and
bleed air from the tire.

 If there is no special tool to

pry off the tire bead, use your feet
to do this as the figure shown.

 After the tire bead is separated

from the rim and before removing
the tire, press the tire bead at the
back of the valve into the rim
groove completely, Then push the
tire to the same side.

When removing the valve core, be
careful that the high tire pressure
may force out the valve core.

＊

It is easier to remove the tire when
it is pushed to the same side of
rim.

＊

•Don‘t step on the wheel rim and

spoke wire.

•Before installing the tire, make

sure that the rim and axle bearing
are not damaged. Be careful during
installation.

＊

Rim Center

20. HIGH-SPEED TIRE

20-8

Apply vegetable soapy water to

the area between the rim and tire
and install the rim protector at the
rim side. Then insert the tire iron to
pry off the tire bead from the rim.
At this time, the tire bead at the
back side of the valve is in the rim
groove completely. After making
sure the above mentioned is done,
remove the tire by following the
sequence of 1234.

 Insert the second tire iron

30_ 50mm from the first one.
Then separate the tire bead from
the rim.

 It is the same as . Use the

first tire iron to pry off tire bead
from the rim, then use the second
one to pry off another part of the
tire rim from the rim (distance:
30_ 50mm) slowly.

Do not use a tool other than the
tire iron for motorcycle tire
removal. Use the wheel rim
protector for removal.

＊

If you want to separate the tire
bead from the rim only by one tire
iron, the tire bead will be deformed
due to using too much force. The
rim will also be damaged seriously.
Avoid this way of removal.

＊

20. HIGH-SPEED TIRE

20-9

 The procedure is the same as

 and . If 1/3 of the tire bead is

separated from the rim, the whole
tire is easily taken off.

When 1/2 of the tire bead is pried

off the rim, the tire will be easily
removed by using only one tire
iron.

The bead at the back side can be

pried off in the same procedures
described in _ .

20. HIGH-SPEED TIRE

20-10

Take out the rim from the tire.

Check the rim valve for damage.
Replace any faulty parts.

RIM VALVE REMOVAL

Cut the rim valve from it bottom.

RIM VALVE INSTALLATION

Apply vegetable soapy water to
facilitate the installation of rim valve.
Apply after other foreign objects are
removed.

• Apply around the valve when

installation.

• Apply to the tire bead while

assembling the tire and rim.

Apply vegetable soapy water to the
inner side of rim valve and then use a
special tool to pull the valve out.

When the tire is replaced, replace
the valve as a set.

＊

Be careful not to damage the rim
valve hole.

＊

Do not use oil or gasoline. Use
vegetable soapy water only.

＊

20. HIGH-SPEED TIRE

20-11

RIM AND TIRE INSPECTION

RIM INSPECTION
Check the rim and remove rust and

rubber materials from the rim.
Air leak will be caused by rim
deformation or cracks.
When the tire or rim has cracks, do
not repair them and immediately
replace with a new one.

THE DEPTH AND WIDTH OF
TIRE SCAR IS OVER 0.5MM AND

1.0MM

TIRE INSPECTION
The tire cannot be repaired and must

be replaced with a new one under the
following conditions.

•Tire crack or break is caused by a

foreign object of 6mm outer radius.

•The layer of tire-contact part falls

off.

•Worn tire tread.

•Worn tire bead.

•Broken tire bead stiffener or other

bead damage.

•Broken fabrics.

•Deflection caused by dragging force.

•Rubber cutting damage.

•Abnormal internal anti-leak rubber.

•Side wall breaks or damage.

•Tire tread depth is under 0.8mm

INSTALLATION

Before installation, check the tire
inside for damage.

Apply vegetable soapy water to the
right and left sides of tire bead. Keep
the tire upright and start to install the
tire from the back of the rim valve
according to the order of 1234.
Then, push the tire into the rim by
hand to the part where hands can
reach in.

When the tire is deformed, repair
and correct the deformed part by
hand.

＊

20. HIGH-SPEED TIRE

20-12

Put the wheel horizontally and put
the rim protector on the rim. Use 2
tire irons to install the tire bead into
the rim slowly (30_ 50mm).

Use 2 tire irons to install the tire bead
for the last 50_ 60mm part. By
this way, one side of the tire bead is
installed.

The installation of the other side of
tire bead should be started from the
opposite side of the tire valve
according to the order of 1234.

20. HIGH-SPEED TIRE

20-13

Install the rim protector and insert 2
tire irons at an interval of 30mm to
install the tire bead into the rim.
Press to hold the installed part of tire
bead by knees.

After 1/2 of tire bead is installed,
insert 2 tire irons at an interval of
30_ 40mm to finish the installation
in order.

The pulled-out tire iron should be
inserted beside the other tire iron
which hasn‘t been pulled out.

After 2/3 of the tire bead is installed
into the rim, make sure if the installed
tire bead is completely inserted into
the rim groove.

• Both tire irons should be pulled

out at the same time.

• The already installed part should

be pressed.

＊

If the tire bead is not completely
inserted into the rim groove, it will
be more difficult to install the rest
part of the tire bead. Moreover,
the rim bead is easily damaged.

＊

20. HIGH-SPEED TIRE

20-14

If 50_ 60mm of the tire bead is not
installed, use 2 tire irons to install the
rest part of tire bead.

Use the valve core installer to install
the valve core.

Apply vegetable soapy water to both
sides of the tire bead.

20. HIGH-SPEED TIRE

20-15

In order to ensure that the tire and the
rim are well combined, raise the wheel
and rotate it. Press around the tire by
hand for several times to see if the tire
is perfectly combined with the rim.

Pump the tire up to the specified tire
pressure. If there is air leak between
tire bead and rim after pumping, turn
the valve down and press the upper
side of the tire with hand to rotate the
tire and pump the air in.

After pumping with specified air
pressure, make sure if the tire bead is
well installed into the rim.

20. HIGH-SPEED TIRE

20-16

HIGH-SPEED TIRE REPAIR

Repair the tire using the repair methods and
repair agents recommended by the
manufacturers.

REPAIR PROCEDURES

First remove the tire from the wheel.
Find the crack and mark it.

Take out foreign objects and check if the
tire can be repaired.

Tire repair

Repair methods are divided into external
and internal repairs.
Perform the external repair first and then
the internal repair.
When repair agent is used, follow the
instructions provided by the manufacturer.

Remove dust and dirt from the tire bead.

Clean out the tire inside. Recheck the
repaired portion and make sure there is no
other damage.

Install the tire and wheel rim.

• Check the rim valve when removing

the tire and wheel rim.

• The gum on the repaired portion

may not completely stick to the
tire within 24 hours after repair, be
careful to control the driving speed
for safety.

＊