ASTM F2663-21a

Standard Test Method for Bead Unseating of Tubeless Passenger and Light Truck Tires

SIGNIFICANCE AND USE
5.1 This test method establishes a standard procedure for the test and provides data that can be related to the force required to unseat the bead of a tire inflated with a specified pressure from the rim. This test method does not establish performance limits or tolerances for tire specifications.
SCOPE
1.1 This test method covers the static non-rolling laboratory method of determination of a tubeless tire’s resistance to bead unseating. The test requires the use of a standardized fixture and load machine. The test is conducted using a defined test pressure and method of determining the resultant force to unseat the tire from the rim.  
1.2 This test method is applicable for all passenger, light truck, and temporary spare tires.  
1.3 The values stated in SI units are to be regarded as standard. The values given in parentheses are for information only.  
1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.5 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

General Information

• Status: Published
• Publication Date: 31-Aug-2021
• ICS: 83.160.10 - Road vehicle tyres
• Technical Committee: F09 - Tires
• Drafting Committee: F09.30 - Laboratory (Non-Vehicular) Testing

Relations

• Refers: ASTM F1502-05(2010) - Standard Test Method for Static Measurements on Tires for Passenger Cars, Light Trucks, and Medium Duty Vehicles
• Effective Date: 01-Dec-2010
• Refers: ASTM F538-09 - Standard Terminology Relating to the Characteristics and Performance of Tires
• Effective Date: 15-Jun-2009
• Refers: ASTM F1502-05 - Standard Test Method for Static Measurements on Tires for Passenger Cars, Light Trucks, and Medium Duty Vehicles
• Effective Date: 01-Jan-2005
• Refers: ASTM F1502-05e1 - Standard Test Method for Static Measurements on Tires for Passenger Cars, Light Trucks, and Medium Duty Vehicles
• Effective Date: 01-Jan-2005
• Refers: ASTM F538-03 - Standard Terminology Relating to the Characteristics and Performance of Tires
• Effective Date: 01-Dec-2003
• Refers: ASTM F1502-94(1999) - Standard Test Method for Static Measurements on Tires for Passenger Cars, Light Trucks, and Medium Duty Vehicles
• Effective Date: 10-Sep-1999
• Refers: ASTM F538-99 - Standard Terminology Relating to the Characteristics and Performance of Tires
• Effective Date: 10-Apr-1999

Overview

ASTM F2663-21a is the internationally recognized standard test method for determining the resistance of tubeless passenger car, light truck, and temporary spare tires to bead unseating. Developed by ASTM International, this laboratory test method outlines a static, non-rolling procedure for accurately measuring the force required to unseat a tire bead from its rim when inflated to a specified pressure. The standard ensures consistent procedures for manufacturers, laboratories, and regulatory agencies, but does not set specific performance limits for compliance.

Bead unseating is a critical safety and performance parameter. The bead, that part of the tire intended to seat securely against the rim, ensures tire integrity during use. Inadequate bead retention can lead to air loss and potential safety hazards. Understanding resistance to bead unseating is essential for tire manufacturers, regulatory bodies, and safety evaluators.

Key Topics

• Bead Unseating Resistance: Outlines the process for measuring the force necessary to dislodge the bead of a tubeless tire from its rim. This data provides insight into tire and wheel assembly integrity and performance.
• Testing Apparatus and Conditions: Requires a standardized fixture, a load machine, bead unseating blocks, calibration devices, and pressure gauges. Testing is conducted at specified inflation pressures and under controlled temperature conditions.
• Applicability: The method is suitable for all types of tubeless passenger car tires, light truck tires, and temporary spare tires. Rim and tire measurements must align with recognized industry standards.
• Report Requirements: Specifies the essential elements for test documentation, including laboratory details, test conditions, equipment calibration status, specific test results, and any deviations from the procedure.
• Safety and Good Laboratory Practice: Emphasizes the necessity for appropriate health, safety, and environmental procedures during testing, and compliance with national and international regulatory standards.

Applications

• Tire Manufacturing Quality Control: Enables manufacturers to evaluate and benchmark bead retention of new designs and production batches, ensuring product safety and reliability before market release.
• Regulatory Compliance Testing: Provides a standardized method for safety agencies and test laboratories to assess tires for compliance with local or international regulations referencing ASTM methods.
• Product Development: Assists engineers in understanding how variations in materials, design, or assembly affect a tire’s resistance to bead unseating, facilitating performance optimization.
• Comparative Analysis: Allows direct comparison of bead retention performance across multiple tire types or brands, supporting procurement, competitive analysis, and risk assessment.
• Industry Standardization: Supports global harmonization efforts by providing a uniform method recognized by organizations such as ETRTO, JATMA, and TRA.

Related Standards

• ASTM F538: Terminology Relating to Characteristics and Performance of Tires - establishes the vocabulary used in tire testing standards.
• ASTM F1502: Test Method for Static Measurements on Tires for Passenger Cars, Light Trucks, and Medium Duty Vehicles - referenced for tire dimension measurements.
• Tire and Rim Association Year Book / ETRTO Standards Manual / JATMA Yearbook: Key industry references for tire and rim specifications and sizing.
• FMVSS 109 (US), ADR 23/01 (Australia), GB/T4504-1998 (China): Examples of national regulations incorporating bead unseating or related tire safety performance criteria.

Practical Value

Following ASTM F2663-21a helps ensure that tires used on passenger cars and light trucks meet rigorous safety expectations regarding their mounting and performance integrity. By providing labs and manufacturers with a clear, repeatable method to assess bead retention, the standard supports enhanced tire safety, reliable product development, and industry-wide quality consistency. Proper application of this standard contributes to safer transportation for consumers and compliance across global markets.

Standards Content (Sample)

This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: F2663 − 21a
Standard Test Method for
Bead Unseating of Tubeless Passenger and Light Truck
Tires
This standard is issued under the fixed designation F2663; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope 3. Terminology
3.1 Definitions:
1.1 This test method covers the static non-rolling laboratory
method of determination of a tubeless tire’s resistance to bead 3.1.1 bead, of a tire, n—part of a tire that comes in contact
with the rim and is shaped to secure the tire to the rim. F538
unseating. The test requires the use of a standardized fixture
and load machine. The test is conducted using a defined test
3.1.2 bead unseating block, n—machined block of cast
pressure and method of determining the resultant force to
aluminum (also known as “shoe”) used on the bead unseating
unseat the tire from the rim.
fixture to press against the tire sidewall. F538
1.2 This test method is applicable for all passenger, light
3.1.3 manufacturer, n—of a tire, the name of a company or
truck, and temporary spare tires.
wholly owned subsidiary making the tire. F538
1.3 The values stated in SI units are to be regarded as 3.1.4 measuring rim, n—any ‘rim’with a width as specified
standard. The values given in parentheses are for information
for the design or measuring rim for a particular tire size
only. designation, and with the ‘bead’seat and flange dimensions in
accordance with publications of tire and rim standards organi-
1.4 This standard does not purport to address all of the
zations current at the time of manufacture. F538
safety concerns, if any, associated with its use. It is the
responsibility of the user of this standard to establish appro- 3.1.5 outside diameter, n—the maximum diameter of a tire
priate safety, health, and environmental practices and deter- when it is mounted and inflated. F538
mine the applicability of regulatory limitations prior to use.
3.1.6 overall width, n—the maximum cross-sectional width
1.5 This international standard was developed in accor-
of a tire, including protective or decorative ribs. F538
dance with internationally recognized principles on standard-
3.1.7 rim, n—the specially shaped circular periphery to
ization established in the Decision on Principles for the
which a tire may be mounted with appropriate bead fitment.
Development of International Standards, Guides and Recom-
F538
mendations issued by the World Trade Organization Technical
3.1.8 rim, test, n—a rim having the configuration and
Barriers to Trade (TBT) Committee.
dimensions suitable for use with a test tire in accordance with
publications of a tire and rim standards organization current at
2. Referenced Documents
the time of tire manufacture. F538
2.1 ASTM Standards:
3.1.9 sidewall, of a tire, n—thatportionofatirebetweenthe
F538 Terminology Relating to Characteristics and Perfor-
tread and the bead. F538
mance of Tires
F1502 Test Method for Static Measurements on Tires for
3.1.10 specified design section width, n—thewidthspecified
Passenger Cars, Light Trucks, and Medium Duty Vehicles
in the publications of tire and rim standards organizations
current at the time of manufacture for a new tire of that size
designation and type when inflated on its “measuring rim.”
F538
This test method is under the jurisdiction of ASTM Committee F09 on Tires
and is the direct responsibility of Subcommittee F09.30 on Laboratory (Non-
3.1.11 tire, light truck, n—a tire of a group prescribed in
Vehicular) Testing.
“Light Truck” or “Commercial” tire sections of industry
Current edition approved Sept. 1, 2021. Published February 2022. Originally
standards manuals such as The European Tyre and Rim
approved in 2007. Last previous edition approved in 2021 as F2663 – 21. DOI:
10.1520/F2663-21A.
Technical Organisation (ETRTO), Japan Automobile Tyre
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Manufacturers Association (JATMA), and The Tire and Rim
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
Association (TRA). The tire will typically have either “LT” or
Standardsvolume information, refer to the standard’s Document Summary page on
the ASTM website. “C” (C-type) as part of the tire size designation.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
F2663 − 21a
3.1.11.1 Discussion—An LTtire is a light truck tire with the 6.5 Means for mounting the tire on a test rim/wheel and
letters “LT” either as a prefix or suffix of the tire size mountingthetestassemblyonthetestingmachineisnecessary.
nomenclature. These tires are typically standardized by
6.6 Test rims/wheels.
JATMAorTRA.AC-typetireisalighttruck(commercial)tire
6.7 Pressure gauge, capable of measuring the pressure
with the letter “C” as a suffix to the tire size nomenclature.
within 63.5 kPa (0.5 psi).
These tires are standardized by ETRTO, and located in the
“Commercial” tire section of the Standards Manual.
7. Sampling
3.1.12 tire, passenger car, n—a tire of a group prescribed in
7.1 A sample is one or more tires taken from a lot as
a passenger tire section of industry standards manuals such as
directed in any applicable specification, or as taken from a
The EuropeanTyre and RimTechnical Organisation (ETRTO),
shipping unit, or as agreed upon between the purchaser and the
Japan Automobile Tyre Manufacturers Association (JATMA),
seller.
or The Tire and Rim Association (TRA).
7.2 Record the manufacturer’s identification, brand name,
3.1.13 tire, pneumatic, n—a hollow tire that becomes load-
tire identification number, tire outside diameter, rim/wheel
bearing upon inflation with air, or other gas, to a pressure
diameter code and width, tire size, tire load identification
above atmospheric. F538
information (including, as appropriate: load range, load index,
3.1.14 tread, of a tire, n—the part of the tire that comes in
standard load, extra load, light load, etc.), and type of tire.
contact with the ground. F538
Visually inspect the tire completely for excessive mold lubri-
3.1.15 unseating, v—the dislodgment of the bead area of a cant and any obvious faults or conditions that could affect the
test.
tire from the portion of the rim designed to hold the bead in
place resulting in loss of inflation pressure. F538
8. Preparation of Apparatus
3.1.16 wheel, n—a rigid structure consisting of a rim con-
8.1 Check fixture for bent arm, loose or binding pivot and
nected to a central disk that permits rotationally centered
flat seating of rim/wheel on the support flange.
attachment to an axle. F538
8.2 On certain equipment designs, check alignment of
4. Summary of Test Method
spherical adaptor and ram from load machine.
4.1 This test method measures the force needed to unseat a
9. Calibration and Standardization
tire from a clean, dry, painted test rim/wheel. The force is
9.1 Calibration standards shall be comprised of instrumen-
applied through a specified bead unseating block and pivoting
tation and measuring apparatus that are used for verification of
load arm set substantially parallel to the tire rim/wheel assem-
theaccuraciesoftheindicating-recordinginstruments,pressure
bly at the start of the test. The force is measured at a specific
setting and travel speeds. Calibration standard accuracy will be
point of the fixture. The point to be contacted on the tire
ascertained by comparison of the standard with primary
sidewall is determined within this test method.
standardsmaintainedbytheNationalInstituteofStandardsand
5. Significance and Use Technology (NIST) or secondary standards traceable to NIST
or applicable national standards. The frequency of calibration
5.1 Thistestmethodestablishesastandardprocedureforthe
shall be as often as necessary to ensure that all functions are
test and provides data that can be related to the force required
within tolerances listed in Section 6.
to unseat the bead of a tire inflated with a specified pressure
from the rim. This test method does not establish performance
10. Conditioning
limits or tolerances for tire specifications.
10.1 The ambient temperature for tire conditioning and in
the test area shall be any known temperature within the range
6. Apparatus
of 24 6 8°C (75 6 15°F) (see Test Method F1502).
6.1 A fixture to hold the tire-rim/wheel assembly as shown
in Annex A1 or equivalent.
11. Procedure
6.2 Testing machine which incorporates a block traveling at 11.1 The tire must be at room temperature before mounting.
50.8 6 1.6 mm/min (2.0 6 0.0625 in./min) which can exert a Wash the tire, dry the bead area and mount the tire on a dry,
force on the fixture at the spherical attachment point (in line clean, corrosion free test rim/wheel without lubrication or
with the centerline of the bead unseating block) or equivalent. adhesives.
6.3 Aforce indicating device that shall have an accuracy of 11.2 Inflate the tire to, but do not exceed, the maximum
61 % of the indicated force in the operating range and shall inflation pressure indicated on the tire sidewall, to seat the
reflect an instantaneous change in force from zero to full scale bead. Verify proper bead seating.
in no more than 3.0 s.
11.3 Immediately reduce the pressure to the specified pres-
6.4 Means for calibration of the testing machine for appl
...

This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: F2663 − 21 F2663 − 21a
Standard Test Method for
Bead Unseating of Tubeless Passenger and Light Truck
Tires
This standard is issued under the fixed designation F2663; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope
1.1 This test method covers the static non-rolling laboratory method of determination of a tubeless tire’s resistance to bead
unseating. The test requires the use of a standardized fixture and load machine. The test is conducted using a defined test pressure
and method of determining the resultant force to unseat the tire from the rim.
1.2 This test method is applicable for all passenger, light truck, and temporary spare tires.
1.3 The values stated in SI units are to be regarded as standard. The values given in parentheses are for information only.
1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility
of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of
regulatory limitations prior to use.
1.5 This international standard was developed in accordance with internationally recognized principles on standardization
established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued
by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
2. Referenced Documents
2.1 ASTM Standards:
F538 Terminology Relating to Characteristics and Performance of Tires
F1502 Test Method for Static Measurements on Tires for Passenger Cars, Light Trucks, and Medium Duty Vehicles
3. Terminology
3.1 Definitions:
3.1.1 bead, of a tire, n—part of a tire that comes in contact with the rim and is shaped to secure the tire to the rim. F538
3.1.2 bead unseating block, n—machined block of cast aluminum (also known as “shoe”) used on the bead unseating fixture to
press against the tire sidewall. F538
3.1.3 manufacturer, n—of a tire, the name of a company or wholly owned subsidiary making the tire. F538
This test method is under the jurisdiction of ASTM Committee F09 on Tires and is the direct responsibility of Subcommittee F09.30 on Laboratory (Non-Vehicular)
Testing.
Current edition approved April 1, 2021Sept. 1, 2021. Published May 2021February 2022. Originally approved in 2007. Last previous edition approved in 20152021 as
F2663 – 15.F2663 – 21. DOI: 10.1520/F2663-21.10.1520/F2663-21A.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
Standardsvolume information, refer to the standard’s Document Summary page on the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
F2663 − 21a
3.1.4 measuring rim, n—any ‘rim’ with a width as specified for the design or measuring rim for a particular tire size designation,
and with the ‘bead’ seat and flange dimensions in accordance with publications of tire and rim standards organizations current at
the time of manufacture. F538
3.1.5 outside diameter, n—the maximum diameter of a tire when it is mounted and inflated. F538
3.1.6 overall width, n—the maximum cross-sectional width of a tire, including protective or decorative ribs. F538
3.1.7 rim, n—the specially shaped circular periphery to which a tire may be mounted with appropriate bead fitment. F538
3.1.8 rim, test, n—a rim having the configuration and dimensions suitable for use with a test tire in accordance with publications
of a tire and rim standards organization current at the time of tire manufacture. F538
3.1.9 sidewall, of a tire, n—that portion of a tire between the tread and the bead. F538
3.1.10 specified design section width, n—the width specified in the publications of tire and rim standards organizations current at
the time of manufacture for a new tire of that size designation and type when inflated on its “measuring rim.” F538
3.1.11 tire, light truck, n—a tire of a group prescribed in “Light Truck” or “Commercial” tire sections of industry standards
manuals such as The European Tyre and Rim Technical Organisation (ETRTO), Japan Automobile Tyre Manufacturers Association
(JATMA), and The Tire and Rim Association (TRA). The tire will typically have either “LT” or “C” (C-type) as part of the tire
size designation.
3.1.11.1 Discussion—
An LT tire is a light truck tire with the letters “LT” either as a prefix or suffix of the tire size nomenclature. These tires are typically
standardized by JATMA or TRA. A C-type tire is a light truck (commercial) tire with the letter “C” as a suffix to the tire size
nomenclature. These tires are standardized by ETRTO, and located in the “Commercial” tire section of the Standards Manual.
3.1.12 tire, passenger car, n—a tire of a group prescribed in a passenger tire section of industry standards manuals such as The
European Tyre and Rim Technical Organisation (ETRTO), Japan Automobile Tyre Manufacturers Association (JATMA), or The
Tire and Rim Association (TRA).
3.1.13 tire, pneumatic, n—a hollow tire that becomes load-bearing upon inflation with air, or other gas, to a pressure above
atmospheric. F538
3.1.14 tread, of a tire, n—the part of the tire that comes in contact with the ground. F538
3.1.15 unseating, v—the dislodgment of the bead area of a tire from the portion of the rim designed to hold the bead in place
resulting in loss of inflation pressure. F538
3.1.16 wheel, n—a rigid structure consisting of a rim connected to a central disk that permits rotationally centered attachment to
an axle. F538
4. Summary of Test Method
4.1 This test method measures the force needed to unseat a tire from a clean, dry, painted test rim/wheel. The force is applied
through a specified bead unseating block and pivoting load arm set substantially parallel to the tire rim/wheel assembly at the start
of the test. The force is measured at a specific point of the fixture. The point to be contacted on the tire sidewall is determined
within this test method.
5. Significance and Use
5.1 This test method establishes a standard procedure for the test and provides data that can be related to the force required to
unseat the bead of a tire inflated with a specified pressure from the rim. This test method does not establish performance limits
or tolerances for tire specifications.
F2663 − 21a
6. Apparatus
6.1 A fixture to hold the tire-rim/wheel assembly as shown in Annex A1 or equivalent.
6.2 Testing machine which incorporates a block traveling at 50.8 6 1.6 mm/min (2.0 6 0.0625 in./min) which can exert a force
on the fixture at the spherical attachment point (in line with the centerline of the bead unseating block) or equivalent.
6.3 A force indicating device that shall have an accuracy of 61 % of the indicated force in the operating range and shall reflect
an instantaneous change in force from zero to full scale in no more than 3.0 s.
6.4 Means for calibration of the testing machine for applied load and rate of application speed are necessary.
6.5 Means for mounting the tire on a test rim/wheel and mounting the test assembly on the testing machine is necessary.
6.6 Test rims/wheels.
6.7 Pressure gauge, capable of measuring the pressure within 63.5 kPa (0.5 psi).
7. Sampling
7.1 A sample is one or more tires taken from a lot as directed in any applicable specification, or as taken from a shipping unit,
or as agreed upon between the purchaser and the seller.
7.2 Record the manufacturer’s identification, brand name, tire identification number, tire outside diameter, rim/wheel diameter
code and width, tire size, tire load identification information (including, as appropriate: load range, load index, standard load, extra
load, light load, etc.), and type of tire. Visually inspect the tire completely for excessive mold lubricant and any obvious faults or
conditions that could affect the test.
8. Preparation of Apparatus
8.1 Check fixture for bent arm, loose or binding pivot and flat seating of rim/wheel on the support flange.
8.2 On certain equipment designs, check alignment of spherical adaptor and ram from load machine.
9. Calibration and Standardization
9.1 Calibration standards shall be comprised of instrumentation and measuring apparatus that are used for verification of the
accuracies of the indicating-recording instruments, pressure setting and travel speeds. Calibration standard accuracy will be
ascertained by comparison of the standard with primary standards maintained by the National Institute of Standards and
Technology (NIST) or secondary standards traceable to NIST or applicable national standards. The frequency of calibration shall
be as often as necessary to ensure that all functions are within tolerances listed in Section 6.
10. Conditioning
10.1 The ambient temperature for tire conditioning and in the test area shall be any known temperature within the range of 24 6
8°C (75 6 15°F) (see Test Method F1502).
11. Procedure
11.1 The tire must be at room temperature before mounting. Wash the tire, dry the bead area and mount the tire on a dry, clean,
corrosion free test rim/wheel without lubrication or adhesives.
11.2 Inflate the tire to, but do not exceed, the maximum inflation pressure indicated on the tire sidewall, to seat the bead. Verify
proper bead seating.
F2663 − 21a
11.3 Immediately reduce the pressure t
...