DRAFT UGANDA STANDARDDUS 1855
First Edition
2018 -mm-dd
Reference number
DUS 1855: 201 8
© UNBS 201 8Moto rcycle rubber wheel inner tubes —SpecificationDUS1855 :2018
ii © UNBS 2018 –All rights re servedCompliance with this standard does not, of itself confer immunity from legal obligations
A Uganda Standard does not purport to include all necessary provisions of a contract. Users are
responsible for its correct application
©UNBS 2018
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilised in any
form or by any means, electronic or mechanical, including photocopying and microfilm, without prior writt en
permission from UNBS.
Requests for permission to reproduce this document should be addressed to
The Executive Director
Uganda National Bureau of Standards
P.O. Box 6329
Kampala
Uganda
Tel:+256 41 7333 2 50/1/2/3
Fax: +256 41 4286 123
E-mail: info@unbs.go.ug
Web: www.unbs.go.ugDUS 1855:2018
©UNBS 2018 –All rights reserved iiiContents Page
Foreword ................................ ................................ ................................ ................................ ............................ iv
1 Scope ................................ ................................ ................................ ................................ ...................... 1
2 Normative references ................................ ................................ ................................ ............................ 1
3 Terms and definitions ................................ ................................ ................................ ........................... 1
4 Requirements ................................ ................................ ................................ ................................ ......... 1
4.1 General properties ................................ ................................ ................................ ................................ .1
4.2 Designation ................................ ................................ ................................ ................................ ............ 1
4.3 Composition ................................ ................................ ................................ ................................ ........... 1
4.4 Compatibility ................................ ................................ ................................ ................................ .......... 2
4.5 Mechanical properties ................................ ................................ ................................ ........................... 3
4.6 Air leakage at valve ................................ ................................ ................................ ............................... 3
4.7 Air leakage of inner tube ................................ ................................ ................................ ...................... 3
5 Packaging ................................ ................................ ................................ ................................ ............... 3
6 Marking and labelling ................................ ................................ ................................ ............................ 3
7 Sampling and criteria for conformity ................................ ................................ ................................ ..4
7.3 Criteria for conformity ................................ ................................ ................................ ........................... 4
8 Test methods ................................ ................................ ................................ ................................ ......... 4
8.1 Compatibility ................................ ................................ ................................ ................................ .......... 4
8.2 Tensile strength, elongation, tensile strengt h of joint ................................ ................................ ......5
8.2.1 Apparatus ................................ ................................ ................................ ................................ ............... 5
8.2.2 Preparation of test piece ................................ ................................ ................................ ...................... 5
8.2.3 Testing method ................................ ................................ ................................ ................................ ......6
8.2.4 Calculation ................................ ................................ ................................ ................................ ............. 6
8.2.5 Test results ................................ ................................ ................................ ................................ ............ 7
8.3 Permanent elongation ................................ ................................ ................................ ........................... 7
8.3.1 Apparatus ................................ ................................ ................................ ................................ ............... 7
8.3.2 Test piece preparation ................................ ................................ ................................ .......................... 7
8.3.3 Testing method ................................ ................................ ................................ ................................ ......7
8.3.4 Test results ................................ ................................ ................................ ................................ ............ 8
8.4 Tensile strength after ageing ................................ ................................ ................................ ............... 8
8.4.1 Apparatus ................................ ................................ ................................ ................................ ............... 8
8.4.2 Test piece preparation ................................ ................................ ................................ .......................... 8
8.4.3 Testing method ................................ ................................ ................................ ................................ ......8
8.4.4 Test results ................................ ................................ ................................ ................................ ............ 8
8.5 Air leakage of valve ................................ ................................ ................................ ............................... 8
8.6 Air leakage of inner rubber ................................ ................................ ................................ ................... 8
Bibliography ................................ ................................ ................................ ................................ ........................ 9DUS1855 :2018
iv © UNBS 2018 –All rights re servedForeword
Uganda National Bureau of Standards (UNBS) is a parastatal under the Ministry of Trade ,Industry and
Cooperatives established under Cap 327 , ofthe Laws of Uganda , as amended .  UNBS is mandated to co -
ordinate the elaboration of standards and is
(a)a member of International Organisation for Standardisation (ISO) and
(b)a contact point for the WHO/FAO Codex Alimentarius Commission on Food Standards, and
(c)the National Enquiry Point on TBT Agreement of the World Trade Organisation (WTO).
The work of preparing Uganda Standards is carried out through Technical Committees. A Technical
Committee is established to deliberate on standards in a given field or are a and consists of key stakeholders
including government, academia, consumer groups, private sector and other interested parties.
Draft Uganda Standards adopted by the Technical Committee are widely circulated to stakeholders and the
general public for com ments. The committee reviews the comments before recommending the draft standards
for approval and declaration as Uganda Standards by the National Standards Council.
The committee responsible for this document is Technical Committee UNBS /TC 8,Transport an d
communication .DRAFT UGANDA STANDARD DUS 1855: 201 8
©UNBS 2017 –All rights reserved 1Motorcycle rubber inner tubes —Specification
1Scope
This Draft Uganda S tandard specifies requirements, sampling and test methods for motorcycle inner tubes
made of natural rubber (hereinafter referred to as inner tube).
2Normative re ferences
The following referenced documents referred to in the text in such a way that some or all of their content
constitutes requirements 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.
US ISO 3877 -3,Tyres, valves and tubes —List of equivalent terms —Part 3: Tubes
US ISO 4249 -1,Motorcycle tyres and rims (Code -designated series) —Part 1: Tyres
3Terms and definitions
Forthe purposes of this document, the terms and definitions given in US ISO 3877 -3apply.
4Requirements
4.1 General properties
The inner tube shall be uniformly balanced in both shape and thickness, and be free from harmful defects
such as cracks, visible f oreign objects, among others . The valve shall be visually inspected ensuring that it is
free from rust and easy to tighten and loosen.
4.2 Designation
Inner tube designation shall conform to tyre designation specified in US ISO 4249 -1.
4.3 Composition
4.3.1 The inner rubber shall be composed of rubber made into a ring -shaped tube with a valve reinforced by
a rubber plate that acts as its base, which is firmly fixed to the inner tube. It shall be aged to form an
integrated part.
4.3.2 Thevalve shall beofone of the following types :
a)rubber base valve (see Figure 1) ; and
b)rubber covered valve (see Figure 2) .DUS 1855: 201 8
2 ©UNBS 201 8–All rights reserve d
Figure 1 —Rubber base valve [Clause 4.3.2a)]
Figure 2 —Rubber covered valve [Clause 4.3.2 b )]
Note Figures 1 and 2 are provided as recommendatio ns.
4.3.3The valve shall be covered and the valve arrow end shall beat the same level as the valve nozzle, or
shall not protrude over 0.5 mm or lower than 1.0 mm from the valve nozzle. A test shall be carried out by
measuring with an appropriate device.
4.4 Compatibility
Inner tubes designated for motorcycle tyres shall be fully compatible with their intended use. A test shall be
carried out in accordance with 8.1.DUS 1855: 201 8
©UNBS 201 8–All rights reserved 34.5 Mechanical properties
The mechanical properties shall be asspecified in Table 1.
Table 1—Mechanical properties of inner tube
Property Criteria for conformity Test method
Tensile strength in MPa shall not be less than 11.7 8.2
Elongation (in percentage) shall not be less than 500
Tensile strength of joint (in MPa) shall not be less
than6.86
Permanent elongation (as a percentage) shall not be
over25 8.3
Tensile strength after ageing decrease shall not be
less than10 8.4
The retaining strength between the valve and tube in
the N shall not be less than500 US ISO 4249 -1
4.6 Air le akage at valve
Air leakage at valve testshall be done in accordance with 8.5.
4.7 Air leakage of inner tube
Air leakage of inner tube shall be carried out in accordance with 8.6.
5Packaging
The tube shall be contained in a package or container that is ca pable of preventing any damage.
6Marking and labelling
6.1 Each inner tube and its package or container shall bear as a minimum a number, letter or mark that
indicates the following information that shall legibly and indelibly bemarked :
a)Designation
b)Manuf acturing code and manufacturing date/Expiry
c)Manufacturer’s name or trademark
d)Country of manufacture
6.2 The inner tube shall be designated in a similar manner to motorcycle tyres under US ISO 4249 -1,
except for the ply rating.
6.3 The inner tube shall be designated by one of the two methods as follows:
a)2.25-17 is applicable to size 2.25 -17 motorcycle tyres ;
b)2.75/3.00 -17 is applicable to sizes 2.75 -17 and 3.00 -17 motorcycle tyres. ; and/orDUS 1855: 201 8
4 ©UNBS 201 8–All rights reserve dc)If the marking is in a foreign language, its meaning shall correspond with the provisions in Thai that
are specified above.
7Sampling and criteria for conformity
7.1 Sampling and acceptance for testing general properties and compatibility shall be done in accordance
with 7.1.1 and 7.1.2 .
7.1.1 Samples shall be drawn at rand om from tubes under the same lot in the number specified in Column
2 of Table 2.
7.1.2 If the number of samples that does not correspond with 4.1and 4.4does not exceed the number
specified in Column 3 of Table 2, tubes under this lot shall be deemed to m eet the requirements of this
standard .
7.2 Sampling and acceptance for valves, mechanical properties, and air leakage of the valve and inner tube
shall be done in accordance with 7. 2.1 and 7. 2.2.
7.2.1 Samples shall be drawn at random from tubes under thesame lot in the number specified in Column
4 of Table 2.
7.2.2 If the number of samples that does not correspond with 4.3.3,4.5,4.6and4.7does not exceed the
number specified in Column 5 of Table 2, tubes under this lot shall bedeemed to meet the requ irements of
this standard .
7.3Criteria for conformity
If the s amples conform ing to the requirements specified in 7.1.1and7.1.2 shall be declared conforming.
Table 2 —Sampling plan for testing general properties, compatibility, valves, mechanical proper ties,
and air leakage of the valve and inner tube
Lot designation General properties and compatibility Valve, mechanical properties, air leakage of
valve and inner tube
Sample size Acceptable
numberSample size Acceptable number
Not exceeding 1200 8 1 3 0
1201 to 3200 13 2 13 1
Over 3201 20 3 20 2
8Testmethods
8.1Compatibility
An inner tube, tyre and rim of the same designation and dimension shall be assembled to ensure that the
inner tube will not become too tense or too lax to the extent that it forms any folds. A visual inspection shall
also be carried out.DUS 1855: 201 8
©UNBS 201 8–All rights reserved 58.2Tensile strength, elongation, tensile strength of joint
8.2.1 Apparatus
The test for tensile strength shall be able to provide a maximum reading with a tolerance of + 2% and the
clamp shallmove at a speed of 500 mm/min + 25 mm /min.
8.2.2 Preparation of test piece
8.2.2.1 Each sample shall be cut following the circumference, as shown in Figure 3, into a dumbbell
shape to get one of the sizes or shapes in Figure 4. Four pieces shall be subjected to tensile strength and
elongation tests and two pieces shall be tested for the tensile strength of the joint, which shall be cut as close
to the centre of the test piece as possible.
Figure 3 —Cutting of test pieces for tensile strength and elong ation test and test on the tensile
strength of the joint
8.2.2.2 The thickness and width of the test piece shall be measured as follows:
a)An instrument for measuring the thickness shall have a scale of 0.01 mm and the flat faced loading
disc shall be 5 mm i n diameter. The pressure load that is applied by the instrument shall be 0.80 +
0.12 N.
t is the thickness of the test pieceDUS 1855: 201 8
6 ©UNBS 201 8–All rights reserve dUnits in millimeters
Figure 4 —Sizes and shapes of test pieces are subjected to tensile strength and elongation tests as
well as tests on the tensile strength of the joint
b)The thickness shall be measured at several spots on the parallel portion of the test piece and the
lowest measured value shall be the thickness of the test piece. However, the measurement should not
be performed when the centre of the loading surface is outside the edge of the test piece.
c)The thickness of the test piece that is prepared for testing the tensile strength of the joint shall be
measured on the right and left sides of the joint at a minimum of two posi tions. The maximum and
minimum values obtained from the measurement shall be deleted and the remaining values shall be
averaged to obtain the thickness of the test piece.
d)The width of the parallel portion of the gauge length shall be measured from the widt h of the cutting
dye.
e)The parallel length shall be correctly and clearly marked with indicators and the centre of the parallel
portion shall be taken as the centre of the gauge length.
f)The sectional area of the test piece shall be calculated as follows:
Sectional area = Thickness x Width of parallel portion
8.2.3 Testing method
8.2.3.1 The test piece shall be firmly gripped by a clamp so that it cannot twist during the test.
8.2.3.1 The test piece shall be pulled at a speed of 500 mm+ 25 mm/min until it br eaks.
8.2.4 Calculati on
8.2.4.1 Tensile strength
AFTa
a
where
Tais the tensile strength in MPa ; and
Fais the maximum load in N ewtons .
A= sectional area of the test piece prior to test (in mm 2).
8.2.4.2 Elongation
100*b00 1
LL LE
where
Ebis the percentage elongation ;
L1is the length in millimetres between indicators at the time of breaking ; and
Lois the gauge length in m illimetres .DUS 1855: 201 8
©UNBS 201 8–All rights reserved 78.2.5 Test results
8.5.2.1 General
The measured valu es of the tensile strength and elongation shall be arranged in order of decreasing
numerical value, indicated respectively as Ta1Ta2Ta3Ta4and E b1Eb2Eb3Eb4and the values
shall be expressed as calculated by the following formulas.
8.2.5.2 In the case of four test pieces,
) (*1.0*3.0 *5.04 3 2 1 a a a a a TT T T T    
) (*1.0*3.0*5.04 3 2 1 b b b b b EE E E E    
8.2.5.3 In the case of two test pieces,
2 1*1.0*9.0a a a T T T  
2 1*1.0*9.0b b b E E E  
8.3Permanent elongation
8.3.1 Apparatus
8.3.1.1 Apparatus capable of drawing and keeping the test piece at the specified length
8.3.1.2 Oven with a temperature control function to keep the temperature at 104 °C-110°C
8.3.2 Test piece preparation
The test piece shall be prepared in accordance with 8.2.2. It shall be cut to obtain the size and shape shown
in Figure 5 by the cutting dye. Two test pieces shall be taken from a sample tube.
Key
t is the thickness in millimetres of the test piece
Figure 5 —Size and shape of the test piece for the permanent elongation test
8.3.3 Testing method
The test piece shall be firmly gripped by a clamp so that twisting cannot occur during the test. Draw the test
piece to 1.5 times the gauge length and keep it at a temperature of 104 °C-110°Cforfivehours. Afterwards,
allow it to cool down to room temperature for two hours. The test piece shall be rapidly released from theDUS 1855: 201 8
8 ©UNBS 201 8–All rights reserve dclamps, and it should be left for at least eight h ours. Measure the gauge length of the test piece and calculate
the permanent elongation in a manner similar to 8.2.4.2.
8.3.4 Test results
Test results shall be denoted as the average of permanent elongation values for each tube as specified in
8.2.5.
8.4Tensile strength after ageing
8.4.1 Apparatus
8.4.1.1 Testing apparatus for tensile strength according to 8.2.1
8.4.1.2 Oven with a temperature control function to keep the temperature at 70 °C+ 1°C.
8.4.2 Test piece preparation
Test pieces shall be prep ared in accordance with 8.2.2 by taking four test pieces from a sample.
8.4.3 Testing method
8.4.3.1 The test pieces shall be aged in the oven at a temperature of 70°C+ 1°Cso that stress will not
occur during the test. The test pieces shall not touch each other or any part of the oven.
8.4.3.2 Take the test pieces out of the oven and leave them at room temperature for at least 16 hours.
They shall then be subject ed to tests pursuant to 8.2.3. The test must be completed within 96 h after taking
them out of the oven. The tensile strength shall be calculated in comparison with the value obtained prior to
ageing.
8.4.4 Test results
Test results shall be denoted as the average values of each tube.
8.5Air leakage of valve
Cut the valve from the inner tube sam ple. Install it on the air pressure equipment and apply approximately
0.85 MPa of pressure into the valve. Press down on the valve arrow several times (2 -3 times) to ensure that it
is not obstructed. Immerse the valve about 20 mm in water in a vertical pos ition. Notice the bubbles and
record the time when the bubbles first occur within fiveminutes after immersion.
8.6Air leakage of inner rubber
Pump up the inner tube with 35 kPa of air pressure. Leave it at room temperature for at least 24 h and check
forleakage by applying the same air pressure and immersing the tube in water for one minute. If the tube
leaks, bubbles will emerge. There shall be no air leakage from any parts of the inner tube.DUS 1855: 201 8
©UNBS 201 8–All rights reserved 9Bibliography
[1] TIS 683 -2530 (1987) ─Thai Industrial Standa rd for Motorcycle Rubber Inner TubesDUS 1855: 201 8
©UNBS 2017 –All rights reserved 11Certification marking
Products that conform to Uganda standards may be marked with Uganda National Bureau of Standards
(UNBS) Certification Mark shown in the figure below.
The use of the UNBS Certification Mark is go verned by the Standards Act, and the Regulations made
thereunder. This mark can be used only by those licensed under the certification mark scheme operated by
the Uganda National Bureau of Standards and in conjunction with the relevant Uganda Standard. The
presence of this mark on a product or in relation to a product is an assurance that the goods comply with the
requirements of that standard under a system of supervision, control and testing in accordance with the
certification mark scheme of the Uganda N ational Bureau of Standards. UNBS marked products are
continually checked by UNBS for conformity to that standard.
Further particulars of the terms and conditions of licensing may be obtained from the Director, Uganda
National Bureau of Standards.
DUS 1855: 201 8
ICS 83.160.10
Price based on 16 pages
©UNBS 2017 –All rights reserved