UN R78 Supplement 4 (03 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 4 to the 03 series of amendments
Supplement 3 → 4
- What changed
- Annex 3, paragraph 1.1.3. adds the ASTM F2493-20 standard reference test tyre as a new way to measure the PBC.
- A PBC obtained with the F2493-20 tyre must be converted into the equivalent value for the ASTM E1136-19 tyre.
- Item (a) now refers to E1136-19 and ASTM Method E1337-19, instead of E1136-93 and E1337-90.
- Why
- The aim is the continuity of ASTM Method E1337 for the determination of the PBC in UN Regulation No. 78.
- ETRTO reported that production of the E1136 reference test tyre would stop in 2020 and that its sales would end by the end of 2021.
- The 2019 version of ASTM standard E1337 adds the new F2493 tyre and gives equations to convert results between the two tyres.
Q1What changed6 changes
New 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, for the PBC measurement. The test speed is 40 mph, as in item (a). A new footnote to item (b) says that the obtained PBC must be converted into the equivalent value for the E1136-19 reference tyre. The conversion uses 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 to ASTM Method E1337-19. Before this supplement, item (a) referred to E1136-93 (Re-approved 2003) and to ASTM Method E1337-90 (Re-approved 2008). The test speed of 40 mph does not change.
Wording and punctuation in paragraph 1.1.3.
The PBC is now measured as determined by the “Type Approval Authority”, not the “approval authority”. Paragraph 1.1.3., “Measurement of PBC”, now ends with a colon. Item (c), “The method specified in the Appendix 1 to this annex”, now ends with a full stop, not a colon.
Q2Why it changed
- Proposed by
- Expert from the International Motorcycle Manufacturers Association (IMMA)
- Working party
- GRVA, 11th session (September–October 2021)
Reasons
The amendment aims at the continuity of ASTM Method E1337 for the determination of the PBC in UN Regulation No. 78. For this, it adds 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 introduce the new SRTT F2493, in addition to the older SRTT E1136. This version of E1337 also gives correlation equations to convert results from SRTT F2493 into SRTT E1136 and back.
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 the production of SRTT E1136 would stop in the course of 2020. ETRTO also reported that the sales of SRTT E1136 would be discontinued by the end of 2021.
Sources (2)
“At the seventy-first session of the Working Party on Noise and Tyres (GRBP) in January 2020, the European Tyre And Rim Technical Organization (ETRTO) reported that the production of SRTT E1136 would stop in the course of 2020”
“its sales would be discontinued by the end of 2021”
The impossibility to buy new SRTT E1136 may hinder the use of ASTM Method E1337 in UN Regulation No. 78. To keep the ASTM method available for new and existing type approvals, an additional reference to SRTT F2493 and the conversion equation is necessary.
Sources (3)
“The impossibility to purchase new SRTT E1136 may hinder the use of ASTM Method E1337 in UN Regulation No. 78.”
“to guarantee the continued availability of the ASTM Method”
“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”
The expert from IMMA proposed 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 11th GRVA session
- —Working party adoptsECE/TRANS/WP.29/GRVA/11Session report, para. 99
- 2021-12Sent to WP.29ECE/TRANS/WP.29/2022/49Text that GRVA sent to WP.29 and AC.1
- 2022-03WP.29 adoptsAdopted at the 186th session
- 2022-10-08In forceC.N.342.2022.TREATIES-XI.B.16.78UN depositary notification
Q3Who is affected
Vehicle manufacturer
- Update the documents that quote Annex 3, paragraph 1.1.3., to the amended text, for example test plans.
- Be ready for a PBC measured with the F2493-20 tyre under item (b), as the Type Approval Authority determines.
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 the PBC procedures that use item (a) to the E1136-19 tyre and ASTM Method E1337-19.
- Make sure that a PBC measured with the F2493-20 tyre is converted into the equivalent E1136-19 value. Check that the conversion uses the correlation equation described in ASTM E1337-19.
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ⓘ This report gives advice only. It is not legal or type-approval advice.