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UN R108 Supplement 6 (00 series) · UNECE Regulation No. 108 (ECE R108) — Uniform provisions concerning the approval for the production of retreaded pneumatic tyres for motor vehicles and their trailers.

UN R108 — Supplement 6 to the 00 series of amendments

Supplement 5 → 6

Adopted at the WP.29 186th sessionEntry into force 2022-10-08
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What changed
  • New paragraph 2.3.3. adds the category of use “Special use tyre”. New paragraph 6.9. gives the characteristics a tyre needs to be classified as a special use tyre or a professional off-road tyre.
  • Paragraph 2.49. now defines “SRTT16” as a second Standard Reference Test Tyre, next to “SRTT14”. In Annex 9, the snow grip index now uses a factor f, with values for SRTT14 and SRTT16.
  • New paragraph 6.6.3.3. covers mould cure tread material(s) and design(s) not covered by paragraphs 6.6.3.1. or 6.6.3.2., “in case of mould cure and pre-cured”. For such tyres that have to fulfil paragraph 7.2., the retreader must give documents to the TAA and the Technical Service issuing the approval.
Why
  • The amendment is required to align the test procedures for retreaded tyres with amendment proposals for UN Regulations Nos. 30 and 117.
  • New paragraph 6.6.3.3. addresses mould-cure or pre-cured tread material(s) not approved according to UN Regulation No. 117 and provided or endorsed by the retreader.
  • The changes allow retreaded C1 tyres to use the POR, ET and “reinforced” or “extra load” definitions and markings, in line with UN Regulation No. 30.

Q1What changed97 changes

Special use and professional off-road tyres (paras. 2.3.1., 2.3.3., 2.3.3.1., 2.54., 4.1.4.3., 4.2.2. and 6.9.)

New paragraph 2.3.3. defines “Special use tyre” as a tyre “intended for mixed use both on- and off-road or for other special duty”, “primarily designed to initiate and maintain the vehicle in motion in off-road conditions”. New paragraph 2.3.3.1. defines “Professional off-road tyre” as a special use tyre primarily used for service in severe off-road conditions. To be classified as a “special use tyre”, a tyre must have “a block tread pattern in which the blocks are larger and more widely spaced than for normal tyres” (para. 6.9.1.). It must also have a tread depth ≥ 11 mm and a void-to-fill ratio ≥ 35 per cent. To be classified as a “professional off-road tyre”, a tyre needs a tread depth ≥ 11 mm, a void-to-fill ratio ≥ 35 per cent and maximum speed rating ≤ Q. Applications for special use tyres must include a copy of the mould drawing of the tread pattern (new para. 4.2.2.).

"Special use tyre" means a tyre intended for mixed use both on- and off-road or for other special duty. These tyres are primarily designed to initiate and maintain the vehicle in motion in off-road conditions.
"Professional off-road tyre" is a special use tyre primarily used for service in severe off-road conditions.
14 more changes in this group — open in Compare

“ET” and “POR” markings and where markings are situated (paras. 3.2.6.2., 3.5., 3.5.1., 3.5.2. and Annex 3)

New paragraph 3.2.6.2. adds the inscription “ET” (Extra Tread) and/or “POR” (Professional Off Road) if the tyre is classified in the category of use “Special use”. Paragraph 3.5. now adds “indelible”, and says “raised above or sunk below the tyre surface” in place of “moulded on to or into the tyre”. New paragraph 3.5.1. says the markings must be situated “in the lower area of the tyre on at least one of its sidewalls”, except for the inscriptions in paragraphs 3.2.1. and 3.2.6.1. Under new paragraph 3.5.2., a date of manufacture that is not moulded must be applied “not later than 24 hours after the tyre is removed from the mould”. In Annex 3, paragraph 1. has a new example figure, and the example now also defines a tyre “of special-use professional off-road (POR) or extra tread (ET) type”. Item (c) of paragraph 3. of Annex 3 adds “ET” and “POR” to the symbols that may be at a distance from the size-designation.

The inscription "ET" and/or "POR" if the tyre is classified in the category of use "Special use. In addition, they may also bear the inscription M+S or M.S or M&S.
ET means Extra Tread and POR means Professional Off Road.
7 more changes in this group — open in Compare

“Radial” and “Reinforced” or “Extra Load” definitions (paras. 2.2.3. and 2.3.6.)

Paragraph 2.2.3. now defines “Radial” or “radial-ply” and says “tyre structure” in place of “pneumatic-tyre structure”. New paragraph 2.3.6. adds a definition of “Reinforced” or “Extra Load” that refers to the standard inflation pressure as specified in ISO 4000-1:2010.

"Radial" or "radial-ply" describes a pneumatic-tyre tyre structure in which the ply cords extend to the beads and are laid substantially at 90E 90° to the centreline of the tread, the carcass being stabilized by an essentially inextensible circumferential belt.
"Reinforced" or "Extra Load" means a pneumatic-tyre structure designed to carry more load at a higher inflation pressure than the load carried by the corresponding standard version tyre at the standard inflation pressure as specified in ISO 4000-1:2010;

Tread material documents and who receives them (paras. 4.1.4.3.1.1., 6.6.3.1. and 6.6.3.2.)

Under paragraphs 6.6.3.1. and 6.6.3.2., all documents now go to the Type Approval Authority and Technical Service issuing the approval, and optionally to the retreader. The former separate lines “To the retreader:” are deleted. Paragraph 6.6.3.1. now also covers “an identical tread pattern design in a mould cure product”, and paragraph 4.1.4.3.1.1. now covers “either pre-cured or mould cure tread material”. In case of mould cure product, the material manufacturer(s) or supplier(s) must also provide tread pattern drawing(s) “including the major features with respect to the snow performance”. The drawing(s) of the tread pattern(s) covered by the UN Regulation No. 117 certificate(s) must now include “the major features with respect to the snow performance”.

For tyres retreaded by using either pre-cured or mould cure tread material with a tread pattern covered by paragraph 6.6.3.1. the list shall clearly identify the tyres in order to make the relevant link with the list(s) quoted in paragraph 6.6.3.1. b). The following table is as example:
For tyres retreaded by using pre-cured tread material(s) or an identical tread pattern design in a mould cure product with a tread pattern not covered by paragraph 6.6.3.2. having to fulfil the requirements of paragraph 7.2. the retreader shall ensure that the material manufacturer(s) or the material supplier(s) of the pre-cured tread material provides to the Type Approval Authority and the Technical Service issuing the approval according to this regulation and optionally to the retreader:
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Mould cure tread material(s) under new paragraph 6.6.3.3., and related tests (paras. 4.1.4.3.1.3., 5.4., 9.2.2., 9.4. and 9.4.2.)

New paragraph 6.6.3.3. covers mould cure tread material(s) and design(s) not covered by paragraphs 6.6.3.1. or 6.6.3.2., “in case of mould cure and pre-cured”. For such tyres that have to fulfil paragraph 7.2., the retreader must give documents to the TAA and the Technical Service issuing the approval. New paragraph 4.1.4.3.1.3. says the list must clearly identify these tyres, to make the link with the list(s) quoted in paragraph 6.6.3.3. b). In paragraph 5.4., the test on at least one sample now applies to each pattern “covered by paragraph 6.6.3.3.”, in place of each pattern “not covered by paragraphs 6.6.3.1. and 6.6.3.2.”. The Type Approval Authority might request a test of compliance “In case of paragraphs 6.6.3.1. and 6.6.3.2.”, in place of “In case of paragraph 6.6.3.2.”. In paragraph 9.2.2., the check of at least 1 tyre once every two years now covers snow tyres for use in severe snow conditions “fulfilling paragraph 6.8.2. and covered by paragraph 6.6.3.3.”.

For tyres retreaded by using mould cure tread material(s) and design(s) not covered by paragraphs 6.6.3.1. or 6.6.3.2. in case of mould cure and pre-cured, having to fulfil the requirements of paragraph 7.2., the retreader shall provide to the Type Approval Authority (TAA) and the Technical Service issuing the approval according to this Regulation:
A copy of the test report(s) as in Annex 10, Appendix 2 and/or 3 of the representative tyre size(s) (see definition in paragraph 2.) demonstrating compliance of the mould cure tread(s) to the requirements of paragraph 7.2.;
8 more changes in this group — open in Compare

SRTT16 reference tyre and factor f (paras. 2.49., 2.51., 7.2.1., 12.4. and Annex 9)

Paragraph 2.49. now also defines “SRTT16” (ASTM F2493-20, size P225/60R16), next to “SRTT14”, and paragraph 7.2.1. now uses “SRTT” in place of “SRTT14”. Annex 9, paragraph 1.3. now defines “Traction test” in place of “Acceleration test”, with ASTM F1805-06 when SRTT14 is the reference tyre or F1805-20 when SRTT16 is. New paragraph 3.1.6. of Annex 9 lists SRTT14 or SRTT16 as the SRTT to use for Class C1 tyres. The snow grip index now uses a factor f: 1.000 with SRTT14, and 0.987 (para. 2.3.) or 0.980 (para. 3.4.1.3.) with SRTT16. Under new paragraph 12.4., Contracting Parties applying this Regulation may continue to grant type approvals “based on snow performance test described in Annex 9 to this Regulation using SRTT14 as reference tyre” until 1 September 2024. A new footnote says SRTT14 will be available from the supplier until the end of October 2021.

"Standard Reference Test Tyre (" or "SRTT)" " means a tyre that is produced, controlled and stored in accordance with the American Society for Testing and Materials (standards of ASTM) standards E1136 – 17 for the size P195/75R14 and referred to as "SRTT14". International:
E1136 – 17 for the size P195/75R14 and referred to as "SRTT14",
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Q2Why it changed

Proposed by
Experts from the Bureau International Permanent des Associations de Vendeurs et Rechapeurs de Pneumatiques (BIPAVER), France and the Netherlands
Working party
GRBP, 74th session (September 2021)

Reasons

  • The amendment is required to align the test procedures for retreaded tyres with amendment proposals for UN Regulation No. 30 and UN Regulation No. 117. The text was also prepared to cover all the tread materials.

    Sources (2)
    “This amendment to UN Regulation No. 108 is required in order to ensure that the test procedures for retreaded tyres are aligned with the amendment proposals”
    “in order to align the provisions for retreaded tyres with the proposals of France for UN Regulation No. 30, of the European Tyre and Rim Technical Organization (ETRTO) for UN Regulation No. 117 and to cover all the tread materials”

  • In paragraph 2.2.3., the word “radial-ply” is added and the word “pneumatic” is deleted. This aligns the definition of “radial tyre structure” in UN Regulation No. 108 with the definition in UN Regulation No. 30. It is premature to introduce the definition proposed for UN Regulation No. 30, because that definition has not been adopted yet.

    Sources (2)
    “Instead the word "radial-ply" has to be added and the word “pneumatic” has to be deleted in order to align the definition of “radial tyre structure" in UN Regulation No. 108 with the definition in UN Regulation No. 30.”
    “It is premature to introduce in this paragraph the definition of “radial tyre structure" which was proposed in ECE/TRANS/WP.29/GRBP/2020/21 for amending UN Regulation No. 30, because the proposed definition has not been adopted yet.”

  • Paragraphs 3.5. to 3.5.2. align the marking requirements for retreaded tyres with the amendment proposed for UN Regulation No. 30. Permanent marking that is neither raised above nor sunk below the tyre surface is a practice largely adopted for retreaded tyres. For this reason, this possibility has to be kept.

    Sources (2)
    “Paragraph 3.5. has to be amended and paragraphs 3.5.1. and 3.5.2 have to be added to ensure that the marking requirements for retreaded tyres are aligned with the amendment proposed in ECE/TRANS/WP.29/GRBP/2020/12 for UN Regulation No. 30.”
    “the possibility of permanently marking retreaded tyres which are neither raised above nor sunk below the tyre surface has to be kept, because this is a practice largely adopted for retreaded tyres.”

  • Paragraph 6.6.3.1. concerns pre-cured tread material(s) not approved according to UN Regulation No. 117 and provided by a supplier. The aim is to clarify the documents to be provided to the Type Approval Authority (TAA) by the retreader. Paragraph 6.6.3.2. is rephrased and renumbered for clarification. New paragraph 6.6.3.3. addresses mould-cure or pre-cured tread material(s) not approved according to UN Regulation No. 117 and provided or endorsed by the retreader. In that case, the retreader provides evidence (test report and CoP). As a consequence, paragraphs 4.1.4.3.1.3., 5.4., 9.2.2., 9.4. and 9.4.2. are added or updated.

    Sources (7)
    “Paragraph 6.6.3.1. concerns pre-cured tread material(s) not approved according to UN Regulation No. 117 and provided by a supplier.”
    “The aim of the proposal is to clarify the documents to be provided to the Type Approval Authority (TAA) by the retreader.”
    “It is rephrasing/renumbering of the paragraph for clarification.”
    “This is a new paragraph in order to address such case, then the retreader shall provide evidence (test report + CoP).”
    “Paragraph 6.6.3.3. concerns mould-cure or pre-cured tread material(s) not approved according to UN Regulation No. 117 and provided or endorsed by the retreader.”
    “Paragraph 4.1.4.3.1.3. is added (list of tyres of the application for approval).”
    “Paragraphs 9.2.2. and 9.4.2. are updated according to the new provisions in paragraph 6.6.3.3.”

  • The changes allow retreaded C1 tyres to use the “professional off-road” (POR) and “extra tread” (ET) definitions and markings, in line with UN Regulation No. 30. They also allow the “reinforced” or “extra load” definitions and markings. New paragraph 6.9. defines the tread parameters for “special use” and “POR”, and new paragraph 4.2.2. allows verification of the “special use” tread parameters.

    Sources (3)
    “modifications are included to allow retreaded C1 tyres to use the “professional off-road” (POR) and “extra tread” (ET), as well as “reinforced” or “extra load” definitions and markings in line with UN Regulation No. 30”
    “Paragraph 6.9. is added to define the tread parameters for “special use” and “POR”.”
    “Paragraph 4.2.2. is added to allow the verification of the “special use” tread parameters.”

Document trail

  1. 2021-07ProposalECE/TRANS/WP.29/GRBP/2021/15Proposal by BIPAVER, France and the Netherlands
  2. —Amended in sessionGRBP-74-35-Rev.1ETRTO changes to new paragraphs 3.2.6.2. and 3.5.1.
  3. —Working party adoptsECE/TRANS/WP.29/GRBP/72Session report, para. 17, with the amendments in Annex III
  4. 2021-12Sent to WP.29ECE/TRANS/WP.29/2022/6Text that GRBP sent to WP.29 and AC.1
  5. 2022-03WP.29 adoptsECE/TRANS/WP.29/1164Adopted at the 186th session (session report, para. 132)
  6. 2022-10-08In forceC.N.351.2022.TREATIES-XI.B.16.108UN depositary notification

Q3Who is affected

Vehicle manufacturer

  • No direct action for this role.

Component supplier

  • Mark “ET” and/or “POR” on retreaded tyres classified in the category of use “Special use” (para. 3.2.6.2.).
  • Check special use tyres against all of paragraph 6.9.1., including tread depth ≥ 11 mm and void-to-fill ratio ≥ 35 per cent.
  • In applications for special use tyres, supply a copy of the mould drawing of the tread pattern (para. 4.2.2.).
  • Under paragraph 6.6.3.3., give the TAA and the Technical Service issuing the approval the documents in items (a) to (d).
  • Put markings in the lower area of at least one sidewall, except paragraphs 3.2.1. and 3.2.6.1. inscriptions (para. 3.5.1.).

Technical service / Approval authority

  • For Class C1 tyres, use SRTT14 or SRTT16 as shown in the table of Annex 9, paragraph 3.1.6.
  • When SRTT16 is the reference tyre, test it at 531 kg and 240 kPa (cold) (Annex 9, para. 2.2.).
  • Compute the snow grip index with the factor f given in Annex 9, paragraphs 2.3. and 3.4.1.3.
  • Be ready for the new documents of paragraph 6.6.3.3. for mould cure tread material(s) and design(s).

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ⓘ This report gives advice only. It is not legal or type-approval advice.

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