UN R54 Supplement 24 (00 series) · UNECE Regulation No. 54 (ECE R54) — Uniform provisions concerning the approval of pneumatic tyres for commercial vehicles and their trailers.
UN R54 — Supplement 24 to the 00 series of amendments
Supplement 23 → 24
- What changed
- The markings and the approval mark no longer need to be moulded on to or into the tyres (para. 3.4.). They must be clearly legible, indelible and raised above or sunk below the tyre surface.
- Tyres with radial structure are now excepted from the ±3.5 per cent outer diameter limit, measured six hours after the load/speed endurance test (para. 6.2.3.).
- Paragraph 2.20. now lists the indication of the structure and the “LT”, “C”, “CP”, “MPT” and “ST” prefixes and suffixes in the tyre-size designation.
- Why
- The definition of the tyre size designation changes in line with Supplement 21 to the 02 series of amendments to UN Regulation No. 30.
- The word “moulded” is a technical limitation linked to the technology available at the time of the first issue of the regulations.
- For radial tyres, the variation of outer diameter measured six hours after the load/speed performance test is far below ±3.5 per cent.
Q1What changed55 changes
Tyre-size designation and indication of the structure (paras. 2.6.2., 2.20. to 2.20.5., 3.1.4. and 3.1.12.)
Paragraph 2.20. now excludes types of tyre whose tyre-size designation is shown in the first column of the tables in Annex 5. The nominal section width item no longer says that the width must be expressed in mm. New paragraph 2.20.3. adds an indication of the structure, placed in front of the rim diameter marking. On diagonal (bias-ply) tyres, it is a dash “-” or the letter “D”; on radial-ply tyres, it is the letter “R”. Before, paragraph 3.1.4.1. allowed no indication or the letter “D” on diagonal (bias-ply) tyres. Paragraph 2.20.5. now contains the rule of paragraph 3.1.12. for tyres first approved after 1 March 2004, and paragraph 3.1.12. reads “(Omitted)”.
“LT”, “C”, “CP”, “MPT” and “ST” in the tyre-size designation (paras. 2.20.6. to 2.20.9., 3.1.14. and 3.1.15.)
New paragraph 2.20.6. adds the prefix “LT” or the suffix “C” or “LT” to the tyre-size designation. Instead of a prefix or a suffix to the tyre-size designation, “LT” may be placed after the service description. Tyres whose tyre-size designation includes the suffix “C” or “CP” may carry the additional inscription “LT” away from the tyre-size designation (para. 3.1.14.). Former paragraphs 3.1.14.1., 3.1.14.2. and 3.1.15. are now 2.20.6.1., 2.20.6.2. and 2.20.7., and paragraph 3.1.16. is now 3.1.15. New paragraph 2.20.8. adds the suffix “MPT” after the rim diameter marking for tyres specifically designed for the equipment of multi-purpose commercial vehicles. New paragraph 2.20.9. adds the prefix “ST” before the nominal section width for tyres specifically designed for the equipment of special trailers.
Markings: moulding, position and date of manufacture (paras. 3.4. to 3.4.2.)
Paragraph 3.4. no longer says that the markings and the approval mark must be moulded on to or into the tyres. They must be clearly legible, indelible and raised above or sunk below the tyre surface. The markings, except the inscriptions in paragraphs 3.1.1. and 3.1.2., must be in the lower area of the tyre on at least one sidewall. Before, paragraph 3.4. also excluded the marking in paragraph 3.1.13. from the lower sidewall rule. A date of manufacture that is not moulded must be applied not later than 24 hours after the tyre is removed from the mould.
Test inflation pressure and service description (paras. 2.35., 4.1.13., 6.2.5. and Annex 3)
In paragraph 6.2.5., the endurance test on a second tyre at the additional load/speed combination is now also at the applicable inflation pressure. At the tyre manufacturer's option, one test at the highest load index, highest speed symbol and lowest test inflation pressure indicated may be submitted. Paragraph 4.1.13. now also lists the applicable inflation pressure, if it differs from the inflation pressure specified according to paragraph 4.1.12. Under new note (3) in Annex 3, a second inflation pressure indication for the additional service description is optional. New item (e) in Annex 3: if there are two test inflation pressure indications, it must be clear which belongs to which load/speed combination. New paragraph 2.35. defines the term “service description”.
Outer diameter after the load/speed endurance test (para. 6.2.3.)
Paragraph 6.2.3. now starts with “Except for tyres with radial structure”. The outer diameter, measured six hours after the load/speed endurance test, must not differ by more than ±3.5 per cent from that before the test. Before, the paragraph had no exception and the limit read “3.5 per cent”.
Wording in Annex 1, Annex 5 (Part II, Table B, notes 4 and 5) and Annex 9
Annex 1, item 4.1., now reads “Tyre-size designation” in place of “Size of tyre”. Note 4 to Annex 5, Part II, Table B, gives the formulas for the outer diameter (D). These formulas now say “Highway Tread” and “Traction Tread” in place of “Normal” and “Snow”, and use “·” in place of “x”. In note 5, the Alpine symbol no longer has “(3PMSF)”, and the references now read “UN Regulation No. 117”. Annex 9, item 5.3., and note 4 no longer end with a quotation mark.
Transitional provisions (paras. 12. to 12.2.)
New paragraph 12. adds transitional provisions. Under paragraph 12.1., Contracting Parties applying this Regulation may continue to grant and/or extend type approvals according to the original version, without Supplement 24. This applies until 3 months after the date of entry into force of Supplement 24. For tyres first approved before the entry into force of Supplement 24, the markings “MPT” and “ST” need not be a prefix or suffix.
Q2Why it changed
- Proposed by
- Experts from the European Tyre and Rim Technical Organization (ETRTO)
- Working party
- GRBP, 72nd session (September 2020)
Reasons
The proposal follows the changes made to UN Regulation No. 30 by Supplement 21 to the 02 series of amendments. It changes the definition of the tyre size designation to include prefixes and suffixes as well as the code for the tyre structure. The proposal also clarifies that the definition is only valid for sizes not listed in Annex 5. Some countries require that all tyres for light commercial vehicles are marked with “LT”. For this reason, the proposal clarifies that the provisions must not be interpreted as prohibiting such an additional marking.
Sources (4)
“In line with the changes introduced in UN Regulation No. 30 by Supplement 21 to the 02 series of amendments”
“it is proposed to change the definition of the tyre size designation by including prefixes and suffixes as well as the code for the tyre structure”
“is it proposed to clarify in the initial paragraph of the section that the following definition is only valid for size that are not listed in Annex 5”
“Because some countries require that all tyres for light commercial vehicles are marked with "LT", it is proposed to clarify that the provisions shall not be interpreted as to prohibit such an additional marking.”
The word “moulded” is a technical limitation linked to the technology available at the time of the first issue of the regulations. Now moulding is only one of the various technical solutions. The removal of this limitation would be advisable, following the principle of not stopping technical innovations. ETRTO proposes to allow tyre marking methods other than moulding. The proposed criteria: any alternative to moulding must make the markings on the tyre sidewall clearly legible and indelible. Also, the date of manufacture must be marked within 24 hours after de-moulding of the tyre.
Sources (5)
“the use of wording “moulded” is a technical limitation linked to the technology available at the time of the first issue of the regulations, but now is only one of the various technical solution.”
“The removal of this technical limitation would be advisable following the principle of not stopping the technical innovations.”
“ETRTO proposes to amend the UN Regulations on tyres in order to allow tyre marking methods other than moulding by keeping the following criteria:”
“Any technical solution alternative to the "moulding" shall guarantee that the markings on the tyre sidewall is clearly legible and indelible.”
“It shall be made sure that the marking of the manufacturing date will be done within 24 hours after de-moulding of the tyre”
For radial tyres, the variation of outer diameter measured six hours after the load/speed performance test is far below ±3.5 per cent. The proposal keeps the measurement of overall diameter after the load/speed test only for diagonal tyres.
Sources (2)
“For radial the variation of outer diameter of the tyre, measured six hours after the load/speed performance test as specified in paragraph 2. of Annex 7, is far below ±3.5 per cent”
“It is proposed to keep the restriction of measurement of overall diameter after load/speed test only to diagonal tyres.”
The proposal aims at clear rules for the indication of the test inflation pressure. It also considers an optional additional test inflation pressure marking for the additional service description. At the same time, it introduces the marking of the test inflation pressure pursuant to UN GTR No. 16. A definition of “service description” is added in line with UN GTR No. 16, because this term is used several times throughout the document.
Sources (3)
“The current proposal aims at providing clear rules for the indication of the test inflation pressure also considering an optional additional test inflation pressure marking for the additional service description”
“introducing at the same time marking of the test inflation pressure pursuant to UN GTR No. 16.”
“It is proposed to introduce a definition of "service description" in line with UN GTR No. 16, because this term is used several times throughout the document.”
The proposal also follows the changes made to UN Regulation No. 30 by Supplement 21 to the 02 series of amendments. The proposal adds a general provision for the gap between a supplement's entry into force and the notification of its adoption to the Contracting Parties. Currently, during this period, the type approval cannot be granted pursuant to the new supplement in force, although it is mandatory. Even after the notification, the Type Approval Authorities and Technical Services may need further time to implement the requirements of the new supplement.
Sources (4)
“In line with the changes introduced in UN Regulation 30 by Supplement 21 to the 02 series of amendments”
“it is proposed to include a general provision addressing the gap between the effective date of entry into force and the date of notification of the adoption of the Supplement to the Contracting Parties.”
“Currently, during this period, the type approval cannot be granted pursuant to the new Supplement in force, although it is mandatory.”
“Even after the notification of the adoption of the Supplement, the Type Approval Authorities and Technical Services may need further time to implement the requirements of the new Supplement.”
Document trail
- 2020-06ProposalECE/TRANS/WP.29/GRBP/2020/13Proposal by ETRTO
- —Amended in sessionGRBP-72-27ETRTO amendments to ECE/TRANS/WP.29/GRBP/2020/13 for the 72nd GRBP session
- —Amended in sessionGRBP-72-30ETRTO amendments to ECE/TRANS/WP.29/GRBP/2020/13 for the 72nd GRBP session
- —Working party adoptsECE/TRANS/WP.29/GRBP/70Session report, para. 13 and Annex V
- 2020-12Sent to WP.29ECE/TRANS/WP.29/2021/5Text that GRBP sent to WP.29 and AC.1
- 2021-03WP.29 adoptsECE/TRANS/WP.29/1157Adopted at the 183rd session (session report, para. 137)
- 2021-09-30In forceC.N.321.2021.TREATIES-XI.B.16.54UN depositary notification
Q3Who is affected
Vehicle manufacturer
- No direct action for this role.
Component supplier
- Except for Annex 5 table sizes, mark diagonal (bias-ply) tyres with “-” or “D” before the rim diameter marking.
- Except for Annex 5 table sizes, add “MPT” for tyres specifically designed for the equipment of multi-purpose commercial vehicles.
- Except for Annex 5 table sizes, add the prefix “ST” for tyres specifically designed for the equipment of special trailers.
- Apply a non-moulded date of manufacture not later than 24 hours after the tyre is removed from the mould.
- If you mark two test inflation pressures, place them so that it is clear which belongs to which load/speed combination.
- If paragraph 6.2.5. applies, give in the application the applicable inflation pressure if it differs from that of paragraph 4.1.12.
Technical service / Approval authority
- Unless the tyre manufacturer opts for one test, test the second tyre of paragraph 6.2.5. at the applicable inflation pressure.
- For the tyre manufacturer's optional single test, use the highest load index, highest speed symbol and lowest test inflation pressure.
- Update your test procedure: paragraph 6.2.3. no longer applies the outer diameter limit to tyres with radial structure.
- Check that the markings and approval mark are clearly legible, indelible and raised above or sunk below the tyre surface.
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ⓘ This report gives advice only. It is not legal or type-approval advice.