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UN R41 Supplement 13 (04 series) · UNECE Regulation No. 41 (ECE R41) — Uniform provisions concerning the approval of motorcycles with regard to noise.

UN R41 — Supplement 13 to the 04 series of amendments

Supplement 12 → 13

Adopted at the WP.29 198th sessionEntry into force 2026-09-30
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What changed
  • For conformity of production tests under paragraph 8.4., the gear determined during type approval now prevails.
  • Before this supplement, the text said that the gear selection requirement of paragraph 1.3.3.3.1.3.1. of Annex 3 must prevail.
Why
  • One reading of the old text was that conformity of production tests should repeat the gear selection procedure of Annex 3.
  • IMMA proposed the added words to make clear that conformity of production tests use the gear determined during type approval.

Q1What changed1 change

Gear for conformity of production tests (para. 8.4.)

Paragraph 8.4. names four causes: substantially different barometric pressure, humidity, temperature or rider mass. These causes can make awot,ref impossible to reach with the same gear in conformity of production as in type approval tests. In this case, the gear determined according to the requirement of paragraph 1.3.3.3.1.3.1. of Annex 3 during type approval must prevail. Before this supplement, the text said that the gear selection requirement of paragraph 1.3.3.3.1.3.1. of Annex 3 must prevail. In both texts, the conformity of production tests can use an acceleration different from awot,ref.

If due to substantially different barometric pressure, humidity, temperature or rider mass, the reference acceleration awot,ref defined in paragraph 1.3.3.3.1.2. of Annex 3 cannot be reached with the same gear in conformity of production as in type approval tests, the gear selection determined according to the requirement of paragraph 1.3.3.3.1.3.1. of Annex 3 during type approval shall prevail and the conformity of production tests can be performed using an acceleration different from awot,ref.
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Q2Why it changed

Proposed by
Experts from the International Motorcycle Manufacturer Association (IMMA)
Working party
GRBP, 82nd session (September 2025)

Reasons

  • The text that GRBP adopted at its 81st session could still be read in different ways. In one reading, conformity of production tests should repeat the gear selection procedure of Annex 3.

    Source
    “the text adopted GRBP at its eighty-first session could still leave room for different interpretations, one of which is that the gear selection procedure should be carried out again for CoP, according to Annex 3.”

  • IMMA proposed added words to make clear that conformity of production tests use the gear determined during type approval.

    Source
    “To avoid this, IMMA proposes to add extra wording to clarify that it is the gear determined during type approval that is the one to be used during the CoP tests.”

  • At its 81st session, GRBP also adopted a proposal for a new 06 series. For this reason, IMMA proposed the same clarification for the 04, 05 and 06 series.

    Sources (2)
    “also at the eighty-first session, GRBP adopted a proposal for a new 06 series of amendments to UN Regulation No. 41”
    “IMMA proposes to introduce this clarification in the 04, 05 and 06 series of amendments to UN Regulation No. 41.”

Document trail

  1. 2025-06ProposalECE/TRANS/WP.29/GRBP/2025/19Proposal by IMMA for the 04, 05 and 06 series
  2. —Working party adoptsECE/TRANS/WP.29/GRBP/80Session report, para. 3
  3. 2026-01Sent to WP.29ECE/TRANS/WP.29/2026/3Text that GRBP sent to WP.29 and AC.1
  4. 2026-03WP.29 adoptsECE/TRANS/WP.29/1190Adopted at the 198th session (session report, para. 114)
  5. 2026-09-30In forceC.N.406.2026.TREATIES-XI.B.16.41UN depositary notification

Q3Who is affected

Vehicle manufacturer

  • Use the gear determined during type approval in your conformity of production tests under paragraph 8.4.
  • Compare your conformity of production test instructions with the amended paragraph 8.4.

Component supplier

  • No direct action for this role.

Technical service / Approval authority

  • Make sure that conformity of production tests under paragraph 8.4. use the gear determined during type approval.
  • Change your local test text for paragraph 8.4. if it uses the old words “gear selection requirement”.

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

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