ISO 9130:2005

Motorcycles — Measurement method for location of centre of gravity

ISO 9130:2005 specifies a measuring method for determining the location of the centre of gravity of the motorcycle and of the motorcycle-rider combination. It is applicable to two-wheeled motorcycles.

Motocycles — Méthode de mesure de l'emplacement du centre de gravité

General Information

• Status: Published
• Publication Date: 21-Apr-2005
• ICS: 43.140 - Motorcycles and mopeds
• Technical Committee: ISO/TC 22/SC 38 - Motorcycles and mopeds
• Drafting Committee: ISO/TC 22/SC 38 - Motorcycles and mopeds
• Current Stage: 9093 - International Standard confirmed
• Completion Date: 02-Apr-2021

Relations

• Revises: ISO 9130:1989 - Motorcycles — Measurement method for location of centre of gravity
• Effective Date: 15-Apr-2008

Standards Content (Sample)

INTERNATIONAL ISO
STANDARD 9130
Second edition
2005-05-01


Motorcycles — Measurement method
for location of centre of gravity
Motocycles — Méthode de mesure de l'emplacement du centre de
gravité





Reference number
ISO 9130:2005(E)
©
ISO 2005

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ISO 9130:2005(E)
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©  ISO 2005
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ii © ISO 2005 – All rights reserved

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ISO 9130:2005(E)
Contents Page
Foreword. iv
Introduction . v
1 Scope. 1
2 Normative references . 1
3 Terms and definitions. 1
4 Measurement conditions. 2
5 Apparatus and measuring instruments . 2
6 Measuring procedure. 3
7 Test results . 16
Annex A (normative) Test report. 17

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ISO 9130:2005(E)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies
(ISO member bodies). The work of preparing International Standards is normally carried out through ISO
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, governmental and
non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the
International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. Draft International Standards
adopted by the technical committees are circulated to the member bodies for voting. Publication as an
International Standard requires approval by at least 75 % of the member bodies casting a vote.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. ISO shall not be held responsible for identifying any or all such patent rights.
ISO 9130 was prepared by Technical Committee ISO/TC 22, Road vehicles, Subcommittee SC 22,
Motorcycles.
This second edition cancels and replaces the first edition (ISO 9130:1989), which has been technically revised.
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ISO 9130:2005(E)
Introduction
The stability of a motorcycle is a very important element of its active safety. The motorcycle–rider combination
and the environment in which this combination is used form a unique closed-loop system. However, the
evaluation of the motorcycle–rider combination stability is extremely complex because of the interaction
between the intrinsic motorcycle stability, the influence of the rider's position and his/her response to
continuously changing conditions.
In the evaluation of motorcycle stability, the determination of the kinetic characteristics of the motorcycle–rider
combination is to be considered an important part of the design parameters of the vehicle itself.
The test procedure specified in this International Standard deals with one aspect of the kinetic characteristics:
the determination of the centre of gravity of the motorcycle and of the motorcycle–rider combination.

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INTERNATIONAL STANDARD ISO 9130:2005(E)

Motorcycles — Measurement method for location of centre
of gravity
1 Scope
This International Standard specifies a measuring method for determining the location of the centre of gravity
of the motorcycle and of the motorcycle–rider combination. It is applicable to two-wheeled motorcycles.
Other measuring methods can be used if it is demonstrated that the results are equivalent.
The measuring results obtained by the method given in this International Standard alone (see Annex A)
cannot be used for an evaluation of the vehicle stability because they deal with only one aspect of this very
complex phenomenon.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated
references, only the edition cited applies. For undated references, the latest edition of the referenced
document (including any amendments) applies.
ISO 3779, Road vehicles — Vehicle identification number (VIN) — Content and structure
1)
49 CFR Part 572, subpart B, Code of Federal Regulations. NHTSA
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
motorcycle axis system
x, y, z
right-hand orthogonal axis system fixed on the motorcycle such that when the motorcycle is moving in a
straight line on a level road, the x-axis is substantially horizontal, points forwards and is in the longitudinal
plane of symmetry, the y-axis points to the rider’s left side and the z-axis points upwards
NOTE 1 This coordinate system applies to translation motion and rotational motion together with the motorcycle.
NOTE 2 Assuming the condition that the motorcycle is fixed to the platform, the coordinate system is also applied to
the platform.
3.2
earth-fixed axis system
X, Y, Z
right-hand orthogonal axis system fixed on the Earth, such that the X- and Y-axes are in a horizontal plane and
the Z-axis points upwards

1) US National Highway Traffic Safety Administration.
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ISO 9130:2005(E)
4 Measurement conditions
4.1 Measurement conditions for a riderless motorcycle are as follows.
a) The motorcycle shall be free from mud and deformation, and shall operate normally.
b) The fuel shall be filled up to the top level specified in the operator's manual.
c) Lubricating oil and cooling water shall be filled up to the level specified in the operator's manual.
d) Tyre pressure shall be as specified in the operator's manual.
e) Tools shall be provided at the regular storage positions.
f) Front and rear suspension systems shall be fixed at a static position.
g) The front wheel shall be positioned along the x-axis.
If the conditions are to be modified according to the object of the measurement, the modified conditions shall
be recorded in the measurement report.
4.2 Measurement conditions when a rider is on the motorcycle are as follows.
a) The measurement conditions of the motorcycle shall be in accordance with 4.1.
b) A test dummy as specified in 49 CFR Part 572, subpart B, or equivalent, having a mass of 73,4 kg, or an
equivalent person, shall be used as the rider.
c) The rider should be positioned on the vertical centre surface of the motorcycle.
d) The rider shall sit on the seat, hold the handle bar by both hands, and place both feet on the foot rests.
e) The rider shall be positioned so as to obtain the angle formed by the line connecting point S (the point
indicating the centre of rotation of the torso and the arms of the rider) and point H (the point indicating the
centre of rotation of the torso and femoral regions of the rider) and the x-axis. This angle shall be the
angle of the rider’s posture.
f) The rider shall be positioned so as to obtain the distance between the front axle and point H along the
x-axis, which shall be the seating position of the rider.
If the conditions are to be modified according to the object of measurement, the modified conditions shall be
recorded in the measurement report.
5 Apparatus and measuring instruments
5.1 Precision square level, able to measure up to 0,1mm / 1m (≈ 20 inches).
5.2 Steel tape measure with a tolerance of ± [0,3 + 0,1(L − 1)] mm at length, L, in metres.
5.3 Angle gauge, able to measure the rotational angle to 0,1° electrically or mechanically.
5.4 Weighing scales, with sufficient accuracy to weigh the object up to 0,1 kg.
5.5 Supports, used when placing the platform on the weighing scale.
5.6 Platform, being of the highest possible rigidity and of light weight.
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ISO 9130:2005(E)
5.7 Knife-edge, the roundness at the edge of which shall be less than 1 mm in radius and whose edge
angle should be less than 90°. The roundness at the edge is the form of edge finished sharply when rounded
with the load applied to it.
5.8 Weights, used to incline the platform.
6 Measuring procedure
6.1 Location of centre of gravity along x-axis
6.1.1 Location of centre of gravity of the empty platform along x-axis
Measure the location of the centre of gravity of the empty platform along the x-axis, as follows. See Figure 1.
a) Place supports respectively at the centres of the front and rear weighing scales and measure loads P
KF
and P .
KR
b) Place the platform on the two supports, such that its centre of gravity lies directly above the line
connecting the two supports. The platform includes any brackets/wires necessary to hold the motorcycle.
If it is difficult to locate the centre of gravity above the line connecting the two supports, use additional
sets of a weighing scale and a support, such that the centre of gravity falls on the area framed by
additional supports and the supports F and R.
c) Measure the distance, x , along the x-axis from point A at the front end of the platform to support F on
PF
the front side, and the distance x along the x-axis from point A to support R on the rear side.
PR
d) Measure loads P and P distributed to the front and rear supports.
FR RR
e) Calculate the distance, x , along the x-axis from point A at the front end of the platform to the centre of
P
gravity using Equations (1) to (3):
PP=−P (1)
PF FR KF
PP=−P (2)
PR RR KR
xP + x P
PF PF PR PR
x = (3)
P
PP+
PF PR
where
P is the load of platform distributed to support F, in newtons (N);
PF
P is the load of platform distributed to support R, in newtons (N);
PR
P is the total of the load given by the platform and the load given by support F, distributed to
FR
support F, in newtons (N);
P is the total of the load given by the platform and the load given by support R, distributed to
RR
support R, in newtons (N);
P is the load of support F, in newtons (N);
KF
P is the load of support R, in newtons (N);
KR
x is the distance from point A at the front end of the platform to the centre of gravity along the x-axis,
P
in millimetres (mm);
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ISO 9130:2005(E)
x is the distance from point A at the front end of the platform to the support F along the x-axis, in
PF
millimetres (mm);
x is the distance from point A at the front end of the platform to support R along the x-axis, in
PR
millimetres (mm).

Figure 1 — Location of centre of gravity of platform along x-axis
6.1.2 Location of centre of gravity of motorcycle along x-axis
For both the case where the motorcycle is riderless (4.1) or has a rider seated on it (4.2), measure the location
of the centre of gravity of a motorcycle along the x-axis, as follows. See Figure 2.
a) Place the motorcycle on the platform, such that the tyre centrelines are parallel to, and vertical above, the
line connecting the two supports, and fix it so it cannot move. The lateral inclination angle of the
motorcycle to the platform shall be 0° ± 0,5°.
b) Measure the distance, x , along the x-axis from point A at the front end of the platform to the front axle of
F
the motorcycle.
c) Measure loads P and P distributed to the front and rear supports.
MF MR
d) Calculate the distance, x , along the x-axis from the front axle of the motorcycle to the location of the
g
centre of gravity using Equations (4) to (9):
mm=−m (4)
mT P
PP=−P (5)
TF MF KF
PP=−P (6)
TR MR KR
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ISO 9130:2005(E)
xP + x P
PF TF PR TR
x = (7)
T
PP+
TF TR
xm − x m
TT P P
x = (8)
m
m
m
xx=−x (9)
gm F
where
m is the mass of the motorcycle, in kilograms (kg);

m
m is the total mass of the motorcycle and platform, in kilograms (kg);

T
m is the mass of the platform, in kilograms (kg);
P
P is the load of the platform and motorcycle distributed to support F, in newtons (N);
TF
P is the load of the platform and motorcycle distributed to support R, in newtons (N);
TR
P is the total of the load given by platform and motorcycle and the load given by support F, distributed

MF
to support F, in newtons (N);
P is the total of the load given by platform and motorcycle, and the load given by support R,

MR
distributed to support R, in newtons (N);
x is the distance from point A at the front end of the platform to the centre of gravity of both
T
motorcycle and platform along the x-axis, in millimetres (mm);
x is the distance from point A at the front end of the platform to the centre of gravity of the motorcycle
m
along the x-axis, in millimetres (mm);
x is the distance from the front axle of the motorcycle to the centre of gravity along the x-axis, in
g
millimetres (mm);
x is the distance from point A at the front end of the platform to the front axle of the motorcycle along
F
the x-axis, in millimetres (mm).
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ISO 9130:2005(E)

Figure 2 — Location of centre of gravity of motorcycle along x-axis
6.2 Location of centre of gravity along y-axis
6.2.1 Location of centre of gravity of the empty platform along y-axis
Measure the location of the centre of gravity of the empty platform along the y-axis, as follows. See Figure 3.
a) Place supports at the centres of the right and left weighing scales and measure loads P and P .
KL KR
b) Place the platform on th
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