UN R124 Supplement 4 (00 series) · UNECE Regulation No. 124 (ECE R124) — Uniform provisions concerning the approval of wheels for passenger cars and their trailers.
UN R124 — Supplement 4 to the 00 series of amendments
Supplement 3 → 4
- What changed
- For aluminium alloy and magnesium alloy wheels, the Annex 4 table now lists tests a, c and e instead of a, b, c and e.
- A new sentence in paragraph 4 of Annex 6 says that a suitable technical test method to detect technical cracks must be applied.
- In the Annex 8 impact test, the acceptance criteria and criterion (c) now name a leak in the wheel; (c) also names wheel deformation.
- Why
- Testing experience confirms that the mechanical properties of the raw materials are not comparable with those of the end product (wheels).
- A suitable test method, for example penetrating paints, can identify small technical cracks (1-5 mm) that could not be seen at visual inspection.
- The intention is to clarify that air leakage caused by tyre damage during the test must not be taken into consideration for the wheel.
Q1What changed4 changes
Annex 4 tests for aluminium alloy and magnesium alloy wheels
For aluminium alloy and magnesium alloy wheels, the Annex 4 table now lists tests a, c and e. Before this supplement, it listed tests a, b, c and e for these materials. Test (b) is a check of mechanical characteristics.
Crack detection in the rotating bending test (Annex 6, para. 4)
New text at the end of paragraph 4 of Annex 6 says that a suitable technical test method to detect technical cracks must be applied. Before this supplement, Annex 6 did not have this sentence.
Loss of inflation pressure in the impact test (Annex 8, paras. 3 and 5)
The acceptance criteria of the Annex 8 impact test now add the words “through a leak in the wheel” after “due to tyre depressurization”. Failure criterion (c) now reads “total loss of inflation pressure within one minute due to deformation of the wheel or a leak in the wheel”. Before this supplement, criterion (c) read “total loss of pressure within one minute”.
Q2Why it changed
- Proposed by
- Expert from Russian Federation
- Working party
- GRBP, 80th session (September 2024)
Reasons
National testing laboratories that test to UN Regulation No. 124 asked for clarification of certain provisions of this Regulation.
Source
“This proposal was prepared in response to requests for clarification of certain provisions of UN Regulation No. 124 received from national testing laboratories engaged in testing in accordance with this UN Regulation.”
Testing experience confirms that the mechanical properties of the raw materials are not comparable with those of the end product (wheels). A check of these characteristics on the end product is considered sufficient. The light-alloy raw material requirements are not necessarily the objective of UN Regulation No. 124.
Sources (2)
“Test (b) is deleted for the case of aluminum-alloy and magnesium-alloy wheels, since the existing experience of testing confirms that the mechanical properties of the raw materials are not comparable with the mechanical properties of the end product (wheels)”
“Verification of such characteristics of the end product is considered to be sufficient, as the light-alloy raw material requirements are not necessarily the objective of UN Regulation No. 124.”
The purpose is to identify cracks that occurred as a result of the test. A suitable test method, for example penetrating paints, can identify small technical cracks (1-5 mm) that could not be seen at visual inspection.
Source
“identify cracks occurred as a result of the test by using a suitable test method, e.g., penetrating paints, allowing to identify small technical cracks (1-5 mm), which could not be seen at visual inspection”
The intention is to clarify that air leakage from tyre damage during the test must not count in the assessment of the wheel test results. The proposal is intended to eliminate uncertainty in the interpretation of the test results.
Sources (2)
“the intention of the proposal is to clarify that the air leakage caused by the tyre damage during the test shall not be taken into consideration when assessing the test results for the wheel”
“The proposal is intended to eliminate uncertainty in the interpretation of the test results.”
For this, the cause of the tyre pressure drop must be determined. If tyre damage caused the pressure drop, this must not affect the acceptance of the wheel.
Sources (2)
“For that, it is necessary to determine the cause of the tyre pressure drop.”
“If the pressure drop in the tyre was caused by its damage, this shall not affect the acceptance of the wheel.”
Document trail
- 2023-11ProposalECE/TRANS/WP.29/GRBP/2024/16Proposal by the expert from Russian Federation
- —RevisedGRBP-79-32Proposal that supersedes ECE/TRANS/WP.29/GRBP/2024/16
- 2024-07RevisedECE/TRANS/WP.29/GRBP/2024/19Revised proposal for the 80th GRBP session
- —Working party adoptsECE/TRANS/WP.29/GRBP/78Session report, para. 30
- 2024-12Sent to WP.29ECE/TRANS/WP.29/2025/5Text that GRBP sent to WP.29 and AC.1
- 2025-03WP.29 adoptsECE/TRANS/WP.29/1184Adopted at the 195th session (session report, para. 109)
- 2025-09-26In forceC.N.525.2025.TREATIES-XI.B.16.124UN depositary notification
Q3Who is affected
Vehicle manufacturer
- No direct action for this role.
Component supplier
- Be ready for a suitable technical test method to detect technical cracks in the Annex 6 rotating bending test.
Technical service / Approval authority
- For aluminium alloy and magnesium alloy wheels, update Annex 4 test plans: the table no longer lists test b.
- For the Annex 6 test, make sure a suitable technical test method to detect technical cracks is applied.
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ⓘ This report gives advice only. It is not legal or type-approval advice.