UN R78 Supplement 2 (04 series) · UNECE Regulation No. 78 (ECE R78) — Uniform provisions concerning the approval of vehicles of categories L1, L2, L3, L4 and L5 with regard to braking.
UN R78 — Supplement 2 to the 04 series of amendments
Supplement 1 → 2
- What changed
- Annex 3, paragraph 1.1.3. adds a new item (b): the ASTM F2493-20 standard reference test tyre for the measurement of the PBC.
- A new footnote requires that a PBC obtained with the F2493-20 tyre is converted into the equivalent value for the E1136-19 tyre.
- Item (a) now refers to ASTM E1136-19 and ASTM Method E1337-19 instead of E1136-93 (Re-approved 2003) and E1337-90 (Re-approved 2008).
- Why
- The proposal aims to keep ASTM Method E1337 available to determine the PBC in UN Regulation No. 78.
- ETRTO reported that production of SRTT E1136 would stop during 2020 and that sales would end by the end of 2021.
- If new SRTT E1136 tyres cannot be bought, the use of ASTM Method E1337 in UN Regulation No. 78 may be hindered.
Q1What changed6 changes
New ASTM F2493-20 reference test tyre in item (b) (Annex 3, para. 1.1.3.)
New item (b) adds the ASTM F2493-20 standard reference test tyre, in accordance with ASTM Method E1337-19, at a speed of 40 mph. The PBC is measured as determined by the Type Approval Authority using item (a), (b) or (c). Under a new footnote to item (b), the obtained PBC must be converted into the equivalent value for the ASTM E1136-19 tyre. The conversion must follow the correlation equation described in ASTM E1337-19.
Updated ASTM references in item (a) (Annex 3, para. 1.1.3.)
Item (a) now refers to the ASTM E1136-19 standard reference test tyre and ASTM Method E1337-19. Before this supplement, item (a) referred to E1136-93 (Re-approved 2003) and E1337-90 (Re-approved 2008). The speed of 40 mph does not change.
Wording and punctuation in Annex 3, paragraph 1.1.3.
Paragraph 1.1.3. now says “Type Approval Authority” instead of “approval authority”. The text “Measurement of PBC” of paragraph 1.1.3. now ends with a colon. Item (c), the method in Appendix 1 to Annex 3, now ends with a full stop instead of a colon.
Q2Why it changed
- Proposed by
- Expert from the International Motorcycle Manufacturers Association (IMMA)
- Working party
- GRVA, 11th session (27 September – 1 October 2021)
Reasons
The proposal aims to keep ASTM Method E1337 available to determine the PBC in UN Regulation No. 78. To do this, the proposal introduces a reference to the new ASTM Standard Reference Test Tyre (SRTT) F2493.
Source
“The objective of this proposal is to ensure the continuity of the ASTM Method E1337 for the determination of the PBC in UN Regulation No. 78, by introducing a reference to the new ASTM Standard Reference Test Tyre (SRTT) F2493”
In 2019, ASTM standard E1337 was updated to add the new SRTT F2493, in addition to the older SRTT E1136. This recent version of ASTM standard E1337 gives correlation equations to convert results between SRTT F2493 and SRTT E1136, in both directions.
Sources (2)
“In 2019, ASTM standard E1337 for the measurement of the PBC was updated to introduce the new SRTT F2493, in addition to the older SRTT E1136.”
“this recent version of ASTM standard E1337 provides correlation equations for converting results obtained with SRTT F2493 into SRTT E1136 and vice-versa”
At the 71st GRBP session in January 2020, ETRTO reported that production of SRTT E1136 would stop during 2020. ETRTO also reported that sales of SRTT E1136 would end by the end of 2021. If new SRTT E1136 tyres cannot be bought, the use of ASTM Method E1337 in UN Regulation No. 78 may be hindered.
Sources (2)
“the European Tyre And Rim Technical Organization (ETRTO) reported that the production of SRTT E1136 would stop in the course of 2020 and its sales would be discontinued by the end of 2021”
“The impossibility to purchase new SRTT E1136 may hinder the use of ASTM Method E1337 in UN Regulation No. 78.”
The proposal says that an additional reference to SRTT F2493 and to the conversion equation of ASTM standard E1337 is necessary. The aim is that the ASTM method stays available for new and existing type approvals to UN Regulation No. 78. The proposal also aims to keep the existing PBC provisions unchanged.
Source
“for new and existing type-approvals to UN Regulation No. 78, it is necessary to introduce an additional reference to the new SRTT F2493 and the conversion equation defined in ASTM standard E1337, while keeping the existing PBC provisions unchanged.”
The expert from IMMA presented ECE/TRANS/WP.29/GRVA/2021/27, which proposes reference updates to standards that were recently revised.
Source
“The expert from IMMA also presented ECE/TRANS/WP.29/GRVA/2021/27, proposing reference updates to standards that were recently revised.”
Document trail
- 2021-07ProposalECE/TRANS/WP.29/GRVA/2021/27Proposal by IMMA for the 03, 04 and 05 series
- —Working party adoptsECE/TRANS/WP.29/GRVA/11Session report, para. 99
- 2021-12Sent to WP.29ECE/TRANS/WP.29/2022/48Text that GRVA sent to WP.29 and AC.1
- 2022-03WP.29 adoptsECE/TRANS/WP.29/1164Adopted at the 186th session (session report, para. 132)
- 2022-10-08In forceC.N.341.2022.TREATIES-XI.B.16.78UN depositary notification
Q3Who is affected
Vehicle manufacturer
- Ask the Type Approval Authority if the PBC measurement will use new item (b), the ASTM F2493-20 tyre.
- Update documents that quote paragraph 1.1.3. of Annex 3 to the amended text.
Component supplier
- No direct action for this role.
Technical service / Approval authority
- Be ready to measure the PBC with the ASTM F2493-20 tyre in accordance with ASTM Method E1337-19 (item (b)).
- Update your PBC procedures for item (a) of paragraph 1.1.3. to ASTM E1136-19 and ASTM Method E1337-19.
- If item (b) is used, check that the PBC is converted to the E1136-19 equivalent with the E1337-19 equation.
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ⓘ This report gives advice only. It is not legal or type-approval advice.