UN R129 — 04 series of amendments

New paragraphs 2.63. to 2.63.6. define the lower tether anchorage (LTA) and six related terms, for example “lower tether strap” and “generic lower tether bracket”. A lower tether is a type of anti-rotation device intended to restrict the rearward rotation of a rearward-facing ECRS. In paragraph 2.12., the anti-rotation device consists of a top-tether strap or a support-leg “in the case of i-Size ECRS”. For a “specific vehicle” ECRS, the list of anti-rotation devices now also names lower tether strap(s). In paragraph 2.14., the definition of “tension relieving device” adds the words “or in the lower tether strap(s)” after “the ISOFIX top tether strap”.

New paragraph 6.3.6. gives lower tether strap specifications for Specific vehicle belted Enhanced Child Restraint Systems. The lower tether straps must fulfil the requirements specified in paragraphs 6.7.4.2. to 6.7.4.4. The lower tether strap length must be at least 900 mm, including the lower tether connector. The lower tether strap must have a no-slack indicator, and the device must meet the requirements of paragraph 6.7.2. An automatically locking retractor that fulfils paragraph 6.7.3.1. can replace the provision for adjustment and release of the tension and the no-slack indicator. For the engagement dimensions of lower tether connectors (hook type), paragraph 6.3.6.5. refers to Figure 3 (c) in paragraph 6.3.4.2.4.

The top tether connector must also be used as the lower tether hook, if applicable (paragraph 6.3.4.1.). New paragraph 6.3.4.2.1. says that the ISOFIX top tether straps must fulfil the requirements specified in paragraphs 6.7.4.2. to 6.7.4.4. Former paragraphs 6.3.4.2.1. to 6.3.4.2.3. are renumbered as paragraphs 6.3.4.2.2. to 6.3.4.2.4. In paragraph 6.3.4.2.3., the no-slack indicator device must now also meet the requirements of paragraph 6.7.2. Figure 3(c) now gives the dimensions of the ISOFIX top tether or lower tether connector (hook type). In paragraph 6.7.4.3.2., the breaking load of not less than 3.6 kN now applies to the restraints of ECRS, instead of i-Size ECRS.

New paragraph 6.3.7. gives generic lower tether bracket and mounting material specifications, for applications where the vehicle manufacturer provides the generic anchorages. Brackets supplied by the child restraint manufacturer must have mounting instructions, including required torque application, and a note that qualified personnel only may fit them. New paragraph 6.3.8. adds two strength tests at 5,000 ± 100 N for each generic lower tether bracket (Figures 3 (j) and 3 (k)). In Annex 24, paragraph 1 now names lower tether anchorages and UN Regulation No. 145. Annex 24 now requires the manufacturer of the child restraint system to describe how it attaches to different vehicles, for assessment by the Technical Service. The child restraint manufacturer must now provide parts for fitting the generic lower tether brackets (if any), instead of parts for fitting the anchorages.

Paragraph 6.3.5. now also applies to Specific Vehicle ECRS that are tested on the test bench according to paragraph 6.6.4.1.2.1. Paragraph 6.6.4.4.1.2.1. has a new sentence after the text on tests under paragraphs 6.6.4.1.6.1.1., 6.6.4.1.6.1.2. or 6.6.4.1.8.2. It applies a tolerance of +10 per cent to the head excursion value distance between the Cr point and plane DF. The dummy should not pass beyond the plane HI, parallel to plane DE. In paragraph 7.1.3.5.2.3., if present, the top tether or lower tether must be adjusted to achieve a tension load of 50 ± 5N. If present, lower tether bracket(s) must be mounted on the Annex 6, Appendix 2, Figure 5 positions and installed according to the user manual.

Items (i) and (j) of paragraph 3.2.2. now have a footnote on the one belt route. One belt route applies over the entire stature range, regardless of the different configurations of use for which the ECRS will be approved. For an ECRS which allows forward and rearward facing orientation, only the one belt route must be used for both configurations. New paragraph 3.5: an ECRS must not bear more than one approval number, except for approving a module as part of different ECRSs. New paragraph 4.6.4. says that only type-approved belt routings must be indicated on the ECRS, in green and no other colour. In paragraph 4.14., item (c) now also names lower tethers and requires one or more of the following symbols as appropriate, instead of one.

From 1 September 2026, Contracting Parties need not accept UN type-approvals to the preceding series first issued after 1 September 2026 (paragraph 16.13.). From 1 September 2027, they need not accept type-approvals issued to the preceding series of amendments (paragraph 16.14.). But Contracting Parties must continue to accept, and grant extensions to, approvals to the preceding series for ECRS not affected by the 04 series changes. The first two digits of the approval number are now 04 (paragraph 5.2.), and the Annex 2 examples now show 042439 and 042450. Annex 27 has new test report rows for paragraphs 6.3.4.2.1. and 6.3.6. to 6.3.8. The Annex 27 introduction no longer says that, for Type Approval Extensions, only the information related to the changes to the ECRS must be provided.