ISO 4250-2:1987
(Main)Narrow and wide base off-road tyres and rims — Part 2: Loads and inflation pressures
Narrow and wide base off-road tyres and rims — Part 2: Loads and inflation pressures
Pneumatiques et jantes à base étroite et à base large pour engins de génie civil — Partie 2: Charges et pressions de gonflage
General Information
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Standards Content (Sample)
I
IS0
INTERNATIONAL STANDARD
4250-2
First edition
1987-12-1 5
INTERNATIONAL ORGANIZATION FOR STANDARDIZATION
ORGANISATION INTERNATIONALE DE NORMALISATION
MEXnYHAPOAHAR OPTAHM3Ai&îR no CTAHflAPTM3Al&iM
Narrow and wide base off-road tyres and rims -
Part 2 :
Loads and inflation pressures
Pneumatiques et jantes à base étroite et à base large pour engins de génie civil -
Partie 2: Charges et pressions de gonflage
Reference number
IS0 4250-2 : 1987 (E)
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'I
Foreword
IS0 (the International Organization for Standardization) is a worldwide federation of
national standards bodies (IS0 member bodies). The work of preparing International
Standards is normally carried out through IS0 technical committees. Each member
body interested in a subject for which a technical committee has been established has
the right to be represented on that committee. International organizations, govern-
mental and non-governmental, in liaison with ISO, also take part in the work.
Draft International Standards adopted by the technical committees are circulated to
the member bodies for approval before their acceptance as International Standards by
the IS0 Council. They are approved in accordance with IS0 procedures requiring at
least 75 % approval by the member bodies voting.
International Standard IS0 4250-2 was prepared by Technical Committee ISO/TC 31,
Tyres, rims and valves.
This first edition and the first editions of IS0 4250-1 and IS0 4250-3 cancel and replace
ISO/TR 4250 : 1980, the three parts together constituting a technical revision.
Users should note that all International Standards undergo revision from time to time
and that any reference made herein.to any other International Standard implies its
latest edition, unless otherwise stated.
O International Organization for Standardization, 1987 0
Printed in Switzerland
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INTERNATIONAL STANDARD IS0 4250-2 : 1987 (E)
Narrow and wide base off-road tyres and rims -
Part 2:
Loads and inflation pressures
operating mass of additional items offered by the manufacturer
O Introduction
which are not replacements for standard items (such as cabs,
body-liners, side-boards, air conditioners, etc.).
IS0 4250 provides technical details on the designation and
dimensions of off-road tyres and rims, as well as load ratings
for these types of tyres. . 3.1.1.3 mass of special modifications: Difference in the
operating mass of the machine due to modifications not
This International Standard consists of three parts :
previously covered in optional equipment mass (such as ad-
ditional reinforcements, etc.).
Part 1 : Tyre designations and dimensions.
3.1.1.4 payload: Total mass of the material being carried.
Part 2 : Loads and inflation pressures.
Part 3: Rims.
3.1.1.5 tyre ballast: (If used, shall also be included in
determination of GMM.)
1 Scope
3.1.1.6 field modifications: Operating mass change due to
machine alterations made other than by the original manufac-
This part of IS0 4250 gives working definitions of masses and
turer (such as modifications for additional capacity, re-
load cycles, and sets out tyre loads and reference inflation
inforcements, etc. I.
pressures for narrow and wide base off-road tyres.
3.2 Definitions of operating conditions
2 Field of application
3.2.1 maximum speed: Peak velocity attained by the
machine.
This part of IS0 4250 applies to tyres primarily intended for off-
road machines.
3.2.2 earth-moving haulage cycle : Cycle where machine
self-loads or receives a load from loading equipment, transports
it elsewhere and returns unloaded. Transportation usually
3 Definitions
occurs over unimproved surfaces at medium speeds, up to
65 kmlh, and short distances, up to 4 km away.
3.1 Definitions of masses
NOTE - Machines in this category are mainly haulage trucks
(dumpers) and tractor-scrapers.
3.1.1 maximum load: Maximum loads of individual tyres
determined by manufacturer’s rated gross machine mass
3.2.3 loader cycle : Cycle where the machine is used to pick
(GMM) distribution assigned to each axle, divided by the
up material and move it a short distance away. Tyre loads fluc-
number of tyres for that axle.
tuate depending on the conditions involved when the equip-
ment picks up the load. Transportation speeds are low, up to
NOTE - The maximum GMM includes masses calculated in 3.1.1.1 to
10 kmlh, and distances are short, usually less than 75 m away.
3.1.1.6 inclusive.
3.2.4 load carry cycle : Cycle where the machine, primarily
3.1.1.1 operating mass (net weight): Actual mass of the
intended for loader service, picks up a load, transports it
base machine with equipment specified by the manufacturer,
elsewhere and returns unloaded. Transportation usually occurs
operator (75 kg), full fuel tank, and full lubricating, hydraulic
over unimproved surfaces at low speeds, up to 25 km/h, and
and cooling systems.
rather short distances, up to 600 m.
3.1.1.2 optional equipment mass : Difference in operating
NOTE - Machines in this category consist mainly of loaders, log
mass between the optional item and standard item replaced
stackers and material handling equipment. Tyre manufacturers should
(such as engine, brakes, tyres, etc.). This includes the be consulted for specific conditions.
1
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IS0 4250-2 : 1987 (E)
Maximum load per tyre shall not be greater than specified in the
3.2.5 dozer (tractor) cycle: Condition where a machine is
used to move materials (usually earth) by pushing, dragging or applicable tables.
grading. Tyre loads are relatively constant and speeds are low,
The performance of machines fitted with off-road tyres
up to 10 km/h. Travel distances vary depending on work situ-
depends on the operating conditions, and more particularly on
ations.
the specific ground pressure which is governed by the inflation
pressure. It is therefore advisable to select tyre size on the basis
3.2.6 grader cycle: Condition where a machine is used in
of low inflation pressure.
construction and road maintenance. Tyre loads are relatively
constant during the work cycles. Grader speeds are slower
during working periods with typical transportation speeds
reaching about 40 km/h. Travel distances vary depending on
6 Inflation pressures - General
work situations.
6.1 Rim and wheel manufacturers should be consulted to
3.2.7 creep: Movement of equipment at a very low speed
determine if the rim and wheel are of sufficient strength for the
(commonly not over 120 m in 60 min). During creep motion,
intended service conditions (inflation pressure and load).
loads on the tyres are usually very high and consideration must
be given to the type of surface over which the equipment is
travelling. Tyre manufacturers should be consulted for specific
6.2 Inflation pressures shown in the load inflation tables are
conditions.
reference pressures and do not include any pressure build-up
due to vehicle operation.
3.2.8 drive-away: Movement of a machine from one loca-
tion to another under non-working conditions. This movement
6.3 In agreement with tyre manufacturers, inflation pressures
occurs during transportation of a machine from site to site.
may be varied to compensate for extremes of atmospheric
Tyre manufacturers should be consulted for specific con-
temperatures or special operating conditions.
ditions.
NOTE - Load/speed/distance tables in this part of IS0 4250 are not
6.4 For all tables the inflation pressures are given for guidance
applicable to drive-away conditions.
only; in actual practice they may vary according to the operating
conditions, in agreement with the tyre manufacturers.
4 Special conditions
For longer hauls and/or speeds in excess of those indicated in
7 Load/inflation tables
the tables, the tyre manufacturers should be consulted for
instructions regarding permissible loads and the required in-
Load/inflation relations for diagonal ply rating tyres are given in
flation pressures.
tables 1 to 4: those for symbol-marked radial tyres are given in
tables 5 and 6.
5 Selection for new machine design
8 Bibliography
Selection of size and strength index of the tyre used on each
axle shall be based on the highest individual wheel load (deter-
by GMM distribution, including load transfer) and the IS0 3877-1, Tyres, valves and tubes - List of equivalent
mined
terms - Part I: Tyres.
machine application.
2
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IS0 4250-2 : 1987 (E)
Table 1 - Diagonal ply rating marked narrow base tyres for earth-moving slow speed service,
reference speed 10 km/h (loaded conditions)
Tyre size Load’) Inflation
PlY Load” Inflation
designation
rating kPa designation rating
kg
14 5 O00 600
12.00 - 20121
16 5 450 700 21 200
~
21.00 - 35 23 000 750
8 4 O00 325
24 300 825
14 5600 575
44 25 000 900
12.00 - 24/25 6 150
16 675 ~~
18 6500 750 28 23 600 575
20 6900 825
32 25 O00 650
21.00 - 49
36 27 250 750
8 4 375 300
40 29000 825
12 5600 450
44 30 750 900
13.00 - 24/25
18 7 100 675
20 7500 750 18 000
22
8 O00 825 24.00 - 25 I 2 I 20000
24 19 Ooo
8 4 875 275
10 5 600 350 24.00 - 29 I 30 I 21800
12
6 300 425
I 36 I 26500 I 650
14.00 - 24/25 16 7 300 550
750
20 8500 700 24.00 - 35 1
1 29000 31500 1 850
24 9 500 850
I 54 I 34500 I 975
28 10 O00 925
36 30 000 650
12 7 100 325
24.00 - 43 32 500
16 8 250 425
20 9 750 550
16.00 - 24/25 24 36 32500 650
10 600 650
24.00 - 49 34500
28 11 500 750
32
12 500 875
36 13 600 975
24 22400 350
27.00 - 33 25 750
12 8 250 275
16 10 O00 375
20 11 500
475
36 36 500 575
24
12 500 550
27.00 - 49 40000
18.00 - 24/25
28 13 600 650
32 15 O00
750
40 45000 575
36 16 O00 850
30.00 - 51 48 750
40 17 O
...
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