Tire basics PDF En

7/27/2019 Tire basics PDF En

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Truck, bus and coach tires

Basics to optimize your

tire perormance


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Contents

3

Truck tires technical basics ................ ................... ................... .................. .

From the very beginning .............. .................. ................... ................... ..........

Today more than ever: tires optimized or specifc uses .................................

Global tire development .................................................................................

Truck tire components and their unctions ............... ................... .................. .

Tire production ...............................................................................................

Legal and standardized markings used on the tire sidewall . ................... .......

Units o measurement and defnitions ............................................................

Unlock your truck tires potential retreading and regrooving ................... ....

Maintenance and care o truck tires

repair, ination, tread depth and storage ........................................................

Damage to truck, bus and coach tires caused by external actors .................

Tread ..............................................................................................................

Sidewall .........................................................................................................

Bead ..............................................................................................................

asics to optimize your tire performance

4

4

6

8

10

12

14

16

18

22

26

28

34

38

Con

ten

ts

Publishers imprint

The content o this publication is provided or inormation only

and without responsibility. Continental Reien Deutschland GmbH

makes no representations about the accuracy, reliability, com-

pleteness or timeliness o the inormation in this publication.

Continental Reien Deutschland GmbH may, in its sole discretion,

revise the inormation contained herein at any time without

notice.

Continental Reien Deutschland GmbHs obligations and respon-

sibilities regarding its products are governed solely by the agree-

ments under which they are sold. Unless otherwise agreed in

writing, the inormation contained herein does not become part

o these agreements. This publication does not contain any

guarantee or agreed quality o Continental Reien Deutsch-land GmbHs products or any warranty o merchantability, itness

or a particular purpose and non-inringement.

Continental Reien Deutschland GmbH may make changes in the

products or services described at any time without notice.

This publication is provided on an as is basis. To the extent per-

mitted by law, Continental Reien Deutschland GmbH makes no

warranty, express or implied, and assumes no liability in connec-

tion with the use o the inormation contained in this publication.

Continental Reien Deutschland GmbH is not liable or any direct,

indirect, incidental, consequential or punitive damages arising

out o the use o this publication. Inormation contained herein is

not intended to announce product availability anywhere in the

world.

The trademarks, service marks and logos (the Trademarks) dis-

played in this publication are the property o Continental Reien

Deutschland GmbH. Nothing in this publication should be con-

strued as granting any license or right to the Trademarks. Without

the express written consent o Continental Reien Deutschland

GmbH the use o the Trademarks is prohibited.

All te xt, i mages, graphics and ot her ma terials in thi s public ation

are subject to the copyright and other intellectual property rights

o Continental Reien Deutschland GmbH. Continental Reien

Deutschland GmbH owns the copyrights in the selection, coordi-

nation and arrangement o the materials in this publication. These

materials may not be modiied or copied or commercial use or

distribution.

Copyright 2011 Continental Reien Deutschland GmbH

All right s reser ved


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Truck tires technical basics

From the very beginning

5

From

thevery

beg

inn

ing

08 onti- randi_ .indd 0 30. 0. 007 :33:5 hr



i i l

- _ 1 . 1 .1 .

- _ 1 . 1 .1 . 7 1- _ 1 . 1 .1 . 7 1

The Continental story is a success story in German

engineering. From the very beginning our company has

been interwoven with the transportation industry. The

result is a broad range o innovations such as the

tubeless tire and a ull line o products tailored to

meet the needs o various sectors within the trans-

portation business.

But all that is possible only because we have always

based the development o our products on a simple,

yet demanding standard: The needs o our customers.

And because these needs are as dierent as t he vari-

ous sectors o the transportation industry themselves,

we still look at things frst through the eyes o our

customers . . .

Weve been partners of the transportation industry ever since tires have

been around. Weve set technological milestones and furthered the develop-

ment of our products. As a company, weve grown at an amazing pace. But

one thing has always stayed the same: The needs of our customers set the

standard for everything we do.

As earl y as the 1950s, Conti nental wa s alrea dy offeri ng speci alized t ires

for various kinds of trucks and buses and tailoring its communication

of specific benefits to each segment.

In the 1960s, tailored product communication for different segments

continued trucks, buses and construction vehicles.



4/21

Today more than ever:

Tires optimized or specifc uses

As partners of the global log istics and transpor tation industry, we are deep ly

familiar with the various sectors of this industry. Thats why we know: cost-

efciency makes all the difference. Our solution: Tires optimized for specic

conditions for every need.

Motorway

Regional

On/Off

Coach

Intercity

Urban

Regional

On/Off

Off

Today, transporters are part o an ever more efcient

global logistics network. As a close companion or our

partners and customers in the global transport and

logistics industry, we understand markets as well as we

understand streets and roads all over the world. We

also know: The bottom line is cost-efciency.

But all streets are not made alike. Nor are various types

o transport. Thats why we have always continued to

develop our product lines or the customer segments

Goods, People and Construction. The result? Tires that

are tailor-made or the specifc conditions aced by

the various sectors o the transportation industry. This

leads to an increase in the proftability o entire eets

considerably.

Goods

People

Construction

7



5/21

Global tire development

9

e engineering is driven primarily by global

onomic development.

is overview shows the main aspects resulting

m this trend.

India China South America/Turkey Europe/NAFTA Europe

ain customer needs Load capacity Load capacity/Mileage Mileage/Load capacity Mileage/Fuel savings Fuel savings/Mileage

ain tire characteristics High durability High durability/Optimized mileage

perormance

Optimized mileage perormance/

High durability

Optimized mileage perormance/

Rolling resistance optimalization

Rolling resistance optimalization/ -

Optimized mileage/Low section tires

ain road characteristics O On/O Regional Regional/Motorway Motorway/Regional

ain eet structure Single owners Single owners Cooperations Fleets Fleets

ain tire tting device Basic tools Basic tools Basic tools/Tire mounting device Tire mounting device Tire mounting device

ain tire type

ain tube type

BIAS tire

Tube type tire

BIAS tire/Radial tire

Tube type tire

Radial tire

Tube type tire/Tubeless tire

Radial tire

Tubeless tire

Radial tire

Tubeless tire

ain rim type

multi-part multi-part multi-part/one-part one-part one-part

pical tire sizes 11.00 20

12.00 20

11.00 20

12.00 20

11.00 R 20

12.00 R 20

11.00 R 20

12.00 R 20

11 R 22.5

12 R 22.5

11 R 22.5

12 R 22.5

315/80 R 22.5

295/80 R 22.5

315/80 R 22.5

295/80 R 22.5

385/65 R 22.5

315/70 R 22.5

315/60 R 22.5


Globa

ltire

deve

lopmen

t

sealing ring

inner tube

apap

inner tube


6/21

Truck tire components and

their unctions

11

natural rubber (30 %)

synthetic rubber (5 %)

halogen butyl r ubber (4 %)

other chemicals (37 %)

core wire (6 %)

nylon abric (1 %)

steel cord (17 %)

Compound:

Structural components:

Materials that go into a truck tire

Component Material Function

1 Tread strip Rubber compound The tread str ip must p rovide h igh wear res istance

and good grip under all road conditions. Some-

times the tread strip consists o two dierent

materials (cap and base). In that case, the base

minimizes tread temperature and rolling resistance.

2 Multi-ply steel belt Steel cords embedded in

rubber compound

Enhances driving stability, reduces rolling

resistance and gives the tire its long service lie.

Restricts casing growth and increases the tiresstructural strength.

3 Steel casing Steel cord Gives the tire structural strength and deection

characteristics, substantially enhances driving

comort.

4 Inner liner Rubber compound Prevents d i usion o ai r and mo isture in tube less

tires.

5 Sidewall Rubber compound Protects rom la te ra l scrubbing and the e ects o

weather.

6 Bead reinforcement Nylon, aramide, steel cord Secures the end o the steel cord ply to the

bead core. Reinorces the bead against high

shear orces.

7 Bead core Steel wire embedded in

rubber compound

Ensures frm ft o the tire to the rim.

Truck tire components and their functions

1

5

4

3

2

6

7

Truc

ktirecomponen

tsan

dthe

irfunc

tions



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Tire production

13

Tirepro

duc

tion

pplier industry

ious s ectors supply th e basic

terials needed to manuacture tires.

e steel industry supplies high

ength steel cords and wires primarily

the manuacture o steel belts and

casing (steel cord) as well as mate-

s used in the bead cores (steel wire).

e chemical industry mostly supplies

nthetic rubber and materials that

prove the grip and durability o tires.

tural rubber (latex) is extracted by

ping rubber trees grown in large

ntations in the tropics.

e textile industry supplies ibers

de o rayon, nylon, polyester etc.

the manuacture o textile cord,

einorcing material, or example

ad reinorcements.

Compound production

Natural and synthetic rubber are mixed

with additives, ollowing pre-defned

ormulas. Many dierent rubber com-

pounds, each optimized or its specifc

unction, are used in modern tires.

Uniormity checks are

perormed.

Manufacture of semi-nished products

Steel cordPre-treated steel cord is embedded into one or

more layers o rubber on a roller and cut to the proper length

or the tire size.

TreadThe kneadable mix o materials is ormed into an endless

strip by means o a screw-like extruder. The strip is cooled and

then cut to size.

Textile cordMany individual textile threads are ed into the calen-

der (large roller) via a special winding device and are embedded in

a thin layer o rubber. This endless sheet is then cut to the desired

width and rewound or urther processing.

Steel beadThe core o the tire bead consists o several individualrubber-coated steel wires ormed into rings.

Sidewall/Inner linerSidewall sections cut to suit the particular

tire size and in various contours are made with the extruder.

A calende r orms the inne r liner i nto a w ide, thi n layer.

s te el c or d s po ol s s te el c or d

calendering

cutting steel cord

to size

rubber portioning

steel industry

(steel cord, steel wire)

building the

casing

inal visual inspection

chemical industry

(synthetic rubber, additives)

rubber extraction(natural rubber)

textile industry

(various cords)

portioning o raw mate-

rials and supplies

production o

master batch

making up o pro-

duction compound

shaping into trans-

portable units

control o unit

weight

cutting the

tread to size

calendering o the

inner liner

sidewall extrusion

bead ring applying the apex

vulcanization check or imbalancesbuilding the tread/

assembling the belt

orce variation

control

x-ray control

Building

All the se compo nents co me

together onto the tire building

machine. They are assembled

in two stages casing and

tread/belt assembly into

what is known as a green

tire.

Vulcanization

Beore vulcanizing the

green tire, it is sprayed

with a special luid.

The green tire takes its inal

orm by being vulcanized in

a curing process or a certain

period o time under pres-

sure. The raw rubber under-

goes a physical change and

becomes vulcanized rubber.

The tread pattern and

sidewall markings o tires

originate in the mold.

Quality control*

Ater v ulcanizat ion the tires

undergo visual inspection

and x-raying.

tread coolingcontrol o weight

per meter

tread extruder

rewinding o

bead wire

coating o

bead wire

unwinding o

bead wire

cutting textile cord

to size

textile cord

calendering

cord abric on

rollers

pre-treating the

green tire


* Each individual stage o produc-tion rom the inspection o the

raw materials through to delivery

o the inished tire is subject to

ongoing quality control.


8/21

Legal and standardized markings

used on the tire sidewall1 Manuacturer

(brand name or logo)

1a Tread pattern reerence

2 Size designation

315 = tire width in mm

80 = aspect ratio (section height to

section width) = 80 %

R = radial construction

22.5 = rim diameter (code)

3 Service description consisting o

156 = load index or single ftment

150 = load index or dual ftment

L = code letter or speed rating

4 Country o manuacture

5 Data as per US saety standard

on inner construction or number o plies,

in this case

tread: under the tread there are fve steel cord

plies (including carcass)

sidewall: viewed rom the side there is one steel

cord ply (in this case the carcass ply)

5a Load range

in accordance with US standard

6 US load designation

o single/dual ftment and indication o

max. ination pressure in kg/kPa (lbs/psi)

1 pound (lbs) = 0.4536 kg

1 pound per square inch (psi) = 6.895 kPa

7 TWI (Tread Wear Indicator)

8 Recommended application

only Continental Truck Tires

9 Regroovable

the manuacturer has designed the tire

or regrooving

10 Tubeless, tube type

11 E = tire complies with value set orth

in ECE-R 54

4 = country code or the country in which

the approval number was issued

(here: 4 = Netherlands)

12 DOT

U. S. Department o Transportation

(responsible or tire saety standards)

13 M+S

Mud and Snow. The manuacturer has designed

the tire or an improved grip/traction perormance

under mud and snow conditions.

14 Identifcation or Brazil

15 Manuacturer code

date o manuacture (week/year)

16 Rotation

recommended direction o rotation

17 Single Point

Alternative load and speed

Legal and standardized markings

Speed index

Speed in km/h

Speed in mph

F

80

50

G

90

56

J

100

62

K

110

68

L

120

75

M

130

81

N

140

87

147

3075

Load index

Load capacity (kg/tire)

148

3150

149

3250

150

3350

151

3450

152

3550

153

3650

154

3750

155

3875

156

4000

The most important markings

e.g. 315/80 R 22.5 156/150 L M tubeless

315 tire width in mm

80 cross-sectional ratio H : W in %

R radial design

22.5 nominal rim diameter o 15 tapered

rim (code)

15

Le

ga

lan

ds

tan

dard

ize

dmark

ingsuse

don

the

tires

idewa

ll

156 4000 kg tire load capacity S

(single tire ftment)

150 3350 kg tire load capacity D

(dual tire ftment)

L speed 120 km/h (75 mph)

( M) alternative permitted operating code

tubeless tubeless type

154

150

156

150


14

3

7

5 6 5a 13 910

11

17

14

12

15

1a

8216


9/21

Units o measurement

and defnitions

M

Lengths

Lengths are given in millimeters.

Rim width

The linear distance between the anges o the rim.

Section height

Hal the dierence between the overall diameter and

the nominal rim diameter.

Tire width

The section width o an inated tire mounted on its

theoretical rim and indicated in the tire size desig-

nation.

Overall diameter

The diameter o an inated tire at the outermost sur-

ace o the tread.

Nominal diameter

It is a size code fgure or reerence purposes only, as

indicated in the tire and rim size designation.

Tire pressure

Tire ination pressure is given in Bar based on cold tire.

Outer diameter new*

Outer diameter is a nominal size which reers to the

tread centre.

Max. outer diameter in service

Max. outer diameter in service is the maximum diam-

eter permitted in the tread center as a result o perma-

nent growth during tire use. Dynamic deormations are

not included.

Cross-section width new*

Cross-section width is a nominal size reerring to the

smooth tire wall.

Max. operational width

Max. operational width is the maximum permitted

width. This includes scu ribs, decorative ribs, lettering

and permanent growth during use. Dynamic deorma-

tions are not included.

Static radius

Static radius is the distance rom the tire center to

ground level. Measurements are checked on ftted tires

inlated to the tire pressure speciied in DIN 70020

Part 5.

Rolling circumerence

Rolling circumerence is the distance covered by one

revolution o the tire.

Load capacities

Load capacities are given in kilograms

(weight = mass).

As a matter of princ iple the technical data in the tables always complies

with the international standards as specied by ISO and the ETRTO. Further

details such as other tire sizes or designs, plus the static radius and the

rolling circumference comply with DIN/WdKguidelines.

17

Un

itso

fmeasuremen

tan

dde

n

itions

W and new when using the measuring rim

A = outer diameter on the ti re

r = static radius

f = deflection under load

M = dual-tire spacing* construction size


W

tire width

rim width

Dual-tire spacing

Maintaining the minimum spacing distance ensures

that the two tires in a dual itment arrangement unc-

tion without violating ETRTO standards, provided the

tires are not itted with chains . In the course o develop-

ment, a variety o designations or tire dimensions

have been introduced, some o which are used con-

currently.

The ollowing combination is most requently used:

Tire width in mm

H : W (height : width) in %

Codes or tire construction (e.g. R or radial

and or crossply and nominal rim diameter

When planning vehicle wheel space, automotive

designers must proceed on the basis o the maximum

values or tire width and outer diameter, taking into

account the tires static and dynamic deormation. In

this way they ensure that all standardly approved tires

will it in all cases. I this is not possible in excep-

tional cases, appropriate measures are to be taken to

exclude any possible risk to saety.

PR

The ply rating, or PR or short, is an internationally used

standard or the structural strength o the tire sub-

structure. The term stems rom the time when cotton

was still used or the abric sub-structure. In those days

PR actually reerred to the number o plies. When ma-

terials with greater strength were introduced, the same

structural durability was achieved with ewer plies. PR

now thereore reers to a load capacity category and is

increasingly being replaces by the load index.

rim

d

H

tir

enewA

A

f

r


10/21

Tread area

Continental truck tires are designed to give you maximum economy

throughout the entire life of the tire and long after that. The following

options show how you can best maximize this potential.

Tire costs are a substantial actor in overall operating costs in the transportation

industry. Purchasing a retreaded tire helps to reduce this actor considerably.

The benefts o Continental truck tires are not just or one lie. Thanks to pro-

essional retreading, they can be given a new lease o lie and deliver the same

quality as a new tire.

In order to urther extend the service lie, a truck tire with the word regroov able

on its sidewall can also be regrooved. This option is suitable or eets which run

their own tire service and have a stock o replacement tires. I the companys

sta have been specially trained in regrooving tires, vehicle downtimes can be

optimized.

Unlock your truck tires potential

retreading and regrooving

19

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spo

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dregroov

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11/21

Retreading

Like new. Allround. Continental truck tires are certainly well worth the invest-

ment. Their performance benets last not only the entire life of the tire; they

can also be used a second time round after the Continental retreading pro-

cess all that in the undiminished quality of a new tire, and under warranty.

Our ContiRe retreading process gives your worn tires a new life, maximizing

their economic efciency.

Manufacturing processes

There are two methods that can be used or tire retread-

ing: hot retreading and cold retreading. Only careully

selected and properly inspected casings are employed

or both o these methods. The manuacturing process

itsel is also identical or both methods, up to the point

o applying the tread material and perorming the vul-

canization.

During hot retreading, the process o applying the tread

material is virtually identical to the production o a new

tire. The tread material is taken directly rom the ex-

truder and applied to the bued casing. Aterwards the

tread/casing assembly is cured in a vulcanization mold

with the required tread pattern. The pattern on the

tread is ormed during the vulcanization process, just

as it is when a new tire is made. Hot retreaded truck

tires rom Continental are retreaded rom bead to bead.

The main advantage o this principle is that the side-

walls are renewed, ensuring that the quality o the hot

retreaded tire is comparable with that o a new tire.

Using the cold retreading method, a patterned and pre-

vulcanized tread is applied to the bued casing. Under

constant tension, this tread is placed along with an

unvulcanized bonding ply onto the bued casing. Evenprior to vulcanization, pre-tensioning ensures that the

tread adapts optimally to the contour o the tire and

that the parts are optimally bonded together when

the tire is in the autoclave. Then the prepared tire is

packed into a curing envelope and vulcanized under

pressure in an autoclave.

Production o a ContiRe retread is carried out in thesame way as production o our new tires. We use ultra-

modern inspection techniques and latest manuactu-

ring methods to guarantee a consistently high level o

product quality. A standardized quality system with

endurance and saety testing ensures thatContiRe re-

treads meet superior quality standards. Not only are

our manuacturing methods, quality systems and in-

spection techniques comparable to those used in the

production o new tires; we even use the same tread

patterns and compounds. And o course, we only use

careully inspected, perect casings with the C2 casing

guarantee or our ContiRe retreads. Indeed, there is no

question that the product characteristics o a ContiRe

retread ully comply with those o our new tires.

Continental casings incorporate frst-class quality and

technological sophistication, making them an extreme-

ly valuable raw material and indeed it is the casing

that orms the basis or retreading. By purchasing a

retread, you are not only easing your tire budget, but

also making an active contribution towards protecting

the environment. Reusing the casing helps save energy

and raw materials. Whats more, maximum utilization o

tire casings means you are helping to reduce the num-

ber o scrap tires and to keep pollution down.

As part o their design, all-steel tru ck tires have a so-called tread stock between the upper edge o the belt

and the tread grooves. This tread stock is intended to

prevent stones and the like rom penetrating into the

steel belt and the casing.

In order to urther increase the service lie, all-steel

truck tires can be regrooved. A tread stock o 2 mm

must remain underneath the additional tread depth

gained by regrooving.

Although tires can be retreaded a ter reaching the legal

wear limit, regrooving is not always advisable. The

tread stock thickness is reduced and stones etc. can

more easily penetrate and damage the steel belts,

leading to rust ormation. This has decidedly negative

eect on the tires suitability or retreading.

The best time or regrooving is when the tread is worn

down to about 3 mm. The tire must then be checked to

make sure the wear is even all round. Attention should

be paid to local or uneven wear patches. Regrooving

should be carried out by an expert, in order to avoid

premature ailure as well as any reduction in the tires

suitability or remolding.

Regrooved tires must not be used on drive axles of

coaches or buses with an extended speed limit of

100 km/h.

The increased tread depth of up to 4 mm achieved

through regrooving means substantially improved

performance.

Regrooving

All Continental ti res approved for regrooving have the word REGROOVABLE

on both sidewalls, in accordance with ECE regulation 54.

tread profile

additional tread

available as a result

of regrooving

steel beltcasing

additional

steel belt

2.0 mm of

under tread

21

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12/21

The correct choice of tire according to the recommendations of the

tire manufacturer is the key to successful maintenance and care.

The high-quality standard o tires assured by the recommendations in this

chapter can be maintained only by regularly checking all the actors or

example by regularly checking tire pressure and conducting external inspection

o the tires (including the inner and outer sidewalls and between dual tires).

For that reason, pressure checking devices and small replacement parts such

as valve inserts, caps and extensions should always be on hand.

Maintenance and care o truck

tires repair, ination, tread depth

and storage

23

Ma

intenancean

dcare

oftruc

ktiresrepa

ir,

ina

tion,

trea

ddep

than

ds

torage



13/21

The ollowing requirements are law in the majority o

European countries:

q Pneumatic tires on trucks and trailers have to eature

tread grooves or sipes round their entire circum-

erence and over the whole width o the tread area.

q The main grooves on truck tires have to have a tread

depth o at least 1 mm, 1.6 mm or 2 mm, depending

on the law in each country. The limit in the UK is

1 mm. The depth o the tread pattern is to be

measured in the grooves or sipes; bridge-like protru-

sions or reinorcements in the tread base should be

ignored in this context.

q On t ires wit h wear indicators (TWI = Tread Wear

Indicators), the tread depth should be measured in

the grooves where the wear indicators are located.

Wear indicators on commercial vehicle tires are

bridge-like protru sions 1.6 mm high, w hich show

whether the tire has reached the wear limit.

Tires should be stored in cool, dry, dark and moderately

ventilated rooms.

Tires which are not ftted on rims should be stored

standing up. Avoid contact with uel, lubricants, sol-

vents and chemicals.

Tires age more quickly i exposed to direct sunlight or

heat.

The tread depth should thereore never be measured

on the wear indicators, but next to them. N. B. Consult

your local Continental ofce or legislation regarding

specifc countries.

Tread depth

Storing tires

Tire damage may initially be just a question o da mage

to the outer rubber. However, this apparently superfcial

damage can eventually extend down to, or into, the

tires reinorcing materials (casing/belt). Thereore no

time should be lost in taking the tire to a specialist

or assessment as soon as any external damage is

detected.

Damage to the reinorcing materials, or instance due

to a nail puncture or a deep cut, is particularly dan-

gerous because dirt and moisture may penetrate during

the time between when the damage occurred and when

it was detected. This may even result in more serious

damage to the reinorcing materials. Damage causing

the reinorcing materials to leak will result in slow losso ination pressure.

The tire is then driven underinated and consequently

subjected to excessive strain. All these actors can

render a tire irreparable by the time the damage is fnal-

ly discovered. I repair is attempted, even by a reput-

able tire specialist, it is possible that tire ailure can still

occur as a result o an overstrained area other than

that originally damaged.

This is why each tire must be careully inspected by a

tire expert beore it is repaired. For only a specially

trained person can decide whether it is possible to

repair the tire and whether the tire will be capable o

delivering sae perormance ater the repair. Repairs

must be carried out by an authorized workshop, which

is then responsible or inspecting the tire and or doingthe job properly. Repairs to wheels are not permitted.

One o the most important causes o excessive tire

wear and damage is incorrect tire pressure. Service

manuals produced by the vehicle manuacturers and

technical documentation rom the tire manuacturers

provide inormation about correct tire pressure. These

values apply without exception to the cold tire, as the

inner pressure o the tire increases during operation.

Tire pressure should be checked every two weeks, at

the latest every our, on the cold tire. Spare tires must

also be checked.

Underination leads to

q increased exing, which makes the tire overheat

and may cause tire ailure

q increased wear, leading to shorter service lie

q higher rolling resistance and subsequently

increased uel consumption

q irregular wear

Tirelifein%

Tire pressure in % of recommended pressure

100

80

60

40

20

0

120 100 80 60 40

When checking tire pressure, be sure to conduct an

visual inspection o t he tire or extern al damage, e. g.

by embedded nails or screws. Missing valve caps and

leaking valves should be replaced immediately.

Tire repairs

Tire ination

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Damage to truck, bus and coach tires may be caused by a variety of

external factors.

For example, improper axle alignment or incorrect storage can damage a tire,

as can driving with insufcient tire pressure. The ollowing chapter describes

common damage to the tread area, the sidewall and the bead caused by

external actors, and gives recommendations that will help you to preventavoidable damage.

Damage to truck, bus and coach

tires caused by external actors

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Abnormal one-sided wear

Cause

Abnormal one-sided tread wear arises as

a result o tire constrainment caused by

wheels being inclined to the direction o

motion. Scale-like or eather-edged wear

is oten seen at the shoulders. This wear

pattern comes about by excessive toe-in/

toe-out values or crooked axles. It also

occurs i corners are regularly taken at

excessive speeds.

Recommendation

Correct axle and wheel alignment

Tread

Abnormal one-sided wear on both sides in shoulder area

Cause

Wear patterns o this nature are caused by

high lateral strain, or example by ast corner-

ing and by underinated tires. A high center

o gravity on the vehicle urther increases this

tendency toward pronounced wear.

Recommendation

Ensure sufcient tire pressure to stabilize thetire cross-section or the load condition.

Abnormal center wear

Cause

Tire pressure too high or high proportion o

journeys without load or only with partial load.

Recommendation

Adjust the tire pressure to the load situation.

Scale-like wear

Cause

Strain caused by slip is a result o high cir-

cumerential or lateral orces and is increased

by excessive tire pressure or insufcient

wheel load.

Recommendation

Adjust the tire pressure to the load situation.

Abnormal one-sided wear in shoulder area

Cause

Occurs predominantly with trailer tires

as a result o

qhigh center o gravity o vehicle

qunsteady loads

qone-sided load distribution

qbent trailer tow-bar

qplay in the trailer coupling ring

Recommendation

When wear patterns o this sort occur, the

vehicle should be checked to see i any o

these possible causes apply.

In order to stabilize the tire cross-section,

be sure to maintain maximum permitted

tire pressure.

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Scale-like

roughening

Burr

formation


16/21

Circumferential damage

Cause

Cuts caused or example by bent or protrud-

ing vehicle parts or by oreign objects trapped

in the wheel house.

Recommendation

Regular inspection o the vehicle and its tires

or such causes.

Cause

Regrooving too deep and going to the belt.

Damage o this nature, combined with the

eect o dirt and moisture, causes the steel

cords to rust. This may render the tire unsuit-

able or retreading. In the fnal stages this can

even lead to premature tire ailure.

Recommendation

Remove the tire immediately and retread it i

possible.

The tire manuacturers instructions regarding

regrooving should be ollowed under all circum-

stances.

Exposed steel cords

Tramline wear

Cause

Unavorable combination o various vehicle

vibrations in low wear use, e. g. on motor-

ways. Only occurs on tires on non-driven

axles (ront axle or trailer).

Free-wheeling grooves have no inuence on

the structural durability o the tire.

Recommendation

In the case o tractor tires: continued use on

driven axle.

Spotty wear

Cause

Dierence in diameter on dual tires.

Varying tire pressure on dual tires. The tire

running on lower pressure is subject to

excessive slip.

Irregularities on the vehicle, e. g. too much

play in bearings or joints or deective sus-

pension.

Recommendation

Only ft dual tires o approximately the same

diameter. Keep both tires in dual arrrange-

ment inated to specifed pressure level.

Remove any play in bearings and/or joints

or repair the suspension (springs, shock

absorbers).

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Cuts

Cause

Eect o sharp-edged objects (stones, glass,

metal, etc.)

Recommendation

I tires with deep localized cuts can be re-

paired or retreaded, this should be done by

a tire expert.

Flat spot

Cause

Localized wear o the size o the ground con-

tact patch, caused by:

qexcessive sharp braking (emergency stop)

qbrakes locking, or example as a result o

incorrect adjustment o the trailer brakes

or deective brakes

Recommendation

qAvoid unneccessary harsh braki ng.

qCheck brakes and braking system and have

adjusted where neccessary.

qInstall automatic anti-lock brake system.

Stressed tread area, cuts caused by spinning, cuts

Cause

Spinning o the drive wheels on stony ground

can be exacerbated by moisture and over-

ination.

Recommendation

Adjust the tire pressu re to the load situation .

Use special tires i necessary.

Break up of the tread due to impact break

Cause

Break in the casing caused by sudden sharp

deormation o the tire, e.g. when driving over

an angular object at high speed.

This is exacerbated by overination or over-

loading.

Recommendation

q I obstacles cannot be avoided, they should

be passed slowly.

qTire pressure should be adjusted to theload situation.

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Inside of the tire

Outside of the tire


18/21

Sidewall

Cause

Eect o sharp-edged objects (stones, glass,

metal, etc.)

Recommendation

I tires with deep localized cuts can be re-

paired or retreaded, this should be done by

a tire expert.

Cuts

Casing rupture due to foreign object trapped

between twin tires

Cause

I stones etc. remain trapped betweendual tires, this may lead to severe sidewall

damage or to a break in the casing.

Recommendation

Regularly check or and remove any trapped

oreign objects. To do this, tires must be

deated and in some cases the outer wheel

removed.

Cause

Rupture in the casing caused by sudden,

sharp deormation o the tire ollowing orce-

ul impact by an obstacle or object.

This is accentuated by excessively high tirepressure or overloading.

Recommendation

q I obstacles cannot be avoided, they

should be passed slowly.

q Tire pressure should be adjusted to the

load situation.

Casing rupture due to impact

Casing rupture due to fatigue

Cause

Temporarily driving with insufcient tire press-

ure or on a at tire, e. g. due to a nail punc-

ture.

Recommendation

q Tires which must be removed prematurely

due to damage should be checked with

particular care or urther usability. Oten it isvery difcult or impossible to establish initial

damaged to the casing, which may lead to

premature tire ailure.

q I a tire in a dual arrangement ails, stop

the vehicle as soon as possible to prevent

the second tire rom being dammaged

as well.

q Adjust the tire pressure to the load situa-

tion.

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Destruction of the casing

Cause

Driving with insufcient tire pressure. Exces-

sive exing and the heat then produced may

cause complete o loss o tire pressure:

q penetrating nails or similar sharp objects

q leaking valves

q deective tubes and bead aps

q hairline cracks in the rim

(or tubeless tires)

Recommendation

q Check tire pressure regularly.

q Establish cause o loss in tire pressure

and rectiy.

q Use only new tubes and bead aps.

Rupture damage

Cause

A sharp-edged oreign object penetrates in

a localized area and causes the casing to

rupture.

Recommendation

Tires damaged in this way cannot normally

be repaired; they must be replaced.

Chang

Cause

Frequent bumping into and scraping along

curbs. Sometimes carcass damage may

result.

Recommendation

q Check the sidewalls regularly.

q I the tire shows excessive wear, ft the

wheel to a less endangered position or

rotate the tire on its rim.

q Replace the tire when the damage goes

as deep as the casing.

q Use a special tire i necessary, e. g. or

buses.

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Nail

Track of damaged area


20/21

Cause

Excessive warmth on brakes and rims as a

result o sustained braking or malunctioning

brakes.

Recommendation

q Regularly check the brakes and the brak-

ing system.

q Use retarder or constant throttle.

Bead damaged due to mounting

Cause

q Using incorrect or sharp-edge ftting tools.

q Fitting without the aid o lubricants.

Note

Excessive warming o the brake drums, lead-

ing to hardening o the beads, can set the

stage or this type o damage.

Recommendation

Follow ftting instructions.

Bead

Scorched bead

Bead damage due to rim

Cause

Locally deormed rim or corrosion o the rim

ange.

Recommendation

q Check the rim or damage and replace i

necessary.

q Remove any rust rom the rim and renew

protective coating beore ftting.

q Use suitable ftting lubricants

(e. g. CONTIFIX).

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Continental Reien Deutschland GmbH

Bttnerstrae 2530165 Hannover

Germany

www.continental-truck-tires.com

www.continental-corporation.com

www.conti360.com 6664C.en2011.0

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