Wet Grip on Worn Tyres (WT)
Reports to GRBP

This group was authorized in 2019 to consider the performance of tyres after initial use. The broad concern is to ensure that somewhat worn tyres continue to comply with the requirements for new tyre approvals (i.e., no serious degradation in performance after initial use and before such wear as would require tyre replacement).

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Meetings (77) Documents Regulations ← Back
Documents 2021
5 Jan 2021 Draft minutes of the 11 December WGWT working group session with test centers WT-17-02
5 Jan 2021 SRTT 16" tread depth wear evolution measurements WT-16-03/Rev.2
5 Jan 2021 Surface roughness studies on buffed tires: Lateral Scanning vs Circumferential Scanning WT-17-03
14 Jan 2021 Draft agenda for the 17th Worn Tyres working group session WT-17-01
19 Jan 2021 SRTT 16" tread depth wear evolution measurements WT-16-03/Rev.3
20 Jan 2021 Status of the Worn Tyres working group work plan WT-17-04
20 Jan 2021 Attendance list from the 17th Worn Tyres working group session WT-17-06
20 Jan 2021 Draft Worn Tyres working group status report to GRBP WT-17-07
17 Feb 2021 Draft agenda for the 18th Worn Tyres working group session WT-18-01
22 Feb 2021 Worn tyres: Draft buffing procedure evaluation sheet WT-18-04
22 Feb 2021 Worn tyres: C2 and C3 considerations WT-18-02
2 Mar 2021 Attendance list from the 18th Worn Tyres working group session WT-18-05
2 Mar 2021 Worn Tyres working group work plan status WT-18-03
2 Mar 2021 Minutes of the 18th Worn Tyres working group session WT-18-06/Rev.1
2 Mar 2021 Final minutes of the 17th Worn Tyres working group session WT-17-08/Rev.1
22 Mar 2021 Agenda for the 19th Worn Tyres working group session WT-19-01/Rev.1
22 Mar 2021 Worn tyres: Concept for C2 and C3 tyres WT-19-02
23 Mar 2021 Worn tyres: Wet grip test issue WT-19-04
23 Mar 2021 Attendance list from the 19th Worn Tyres working group session WT-19-05
23 Mar 2021 Effect of Tyre Mean Texture Depth on µ peak and Average Deceleration WT-17-05/Rev.1
25 Mar 2021 Worn tyres: Minutes of ETRTO-CATARC discussion on 9 March 2021 WT-19-03
25 Mar 2021 Draft minutes of the 19th Worn Tyres working group session WT-19-06
25 Mar 2021 Status of the Worn Tyres working group work plan WT-19-07
16 Apr 2021 Agenda for the 20th Worn Tyres informal group session WT-20-01
21 Apr 2021 Consolidated comments on C2/C3 worn tyres wet grip test proposal WT-20-02
27 Apr 2021 Worn Tyres informal group work plan status WT-20-03
27 Apr 2021 Draft minutes from the 20th Worn Tyres informal group session WT-20-05
27 Apr 2021 Attendance list from the 20th Worn Tyres working group session WT-20-04
18 May 2021 UN R117: Supplement 13 excerpts relevant to worn tyres WT-21-04
20 May 2021 Draft agenda for the 21st Worn Tyres working group session WT-21-01/Rev.2
20 May 2021 Worn tyres: Results of buffing procedure evaluations WT-21-05
21 May 2021 Supplement 13 to UN R117 WT-21-03/Rev.1
28 May 2021 Draft minutes of the 21st Worn Tyres working group session WT-21-06
14 Jun 2021 Agenda for the 22nd Worn Tyres group session WT-22-01
15 Jun 2021 UN R117: Draft Supplement 13 to the 02 series of amendments WT-22-02/Rev.1
20 Jun 2021 Minutes of the 22nd Worn Tyres working group session WT-22-06
20 Jun 2021 Draft presentation on worn tyres post processing provisions WT-22-05
20 Jun 2021 Draft minutes from the 3rd Worn Tyres Post Processing subgroup session WT-22-04
20 Jun 2021 Attendance list from the 22nd Worn Tyres working group session WT-22-03
21 Jun 2021 UN R117: Comments on the draft provisions for worn tyre wet grip WT-23-04
21 Jun 2021 UN R117: Comments on the draft provisions for worn tyres WT-23-03
21 Jun 2021 Agenda for the 23rd Worn Tyres working group session WT-23-01
1 Jul 2021 UN R117: Proposal for amendments WT-23-06
1 Jul 2021 Attendance list from the 23rd Worn Tyres working group session WT-23-05
1 Jul 2021 Draft minutes of the 23rd Worn Tyres working group session WT-23-07
28 Jul 2021 Agenda for the 24th Worn Tyres working group session WT-24-01
28 Jul 2021 Worn Tyres Post Processing status report WT-24-02
30 Jul 2021 Worn tyres: Draft proposal for amendments to UN R117 WT-24-05
30 Jul 2021 Attendance list from the 24th Worn Tyres working group session WT-24-03
30 Jul 2021 Draft minutes of the 24th Worn Tyres working group session WT-24-04
9 Aug 2021 Agenda for the 25th Worn Tyres working group session WT-25-01
24 Aug 2021 Water depth vs SRTT Average μpeak WT-24-06/Rev.1
30 Aug 2021 Attendance list from the 25th Worn Tyres informal group session WT-25-03
30 Aug 2021 UN R117: 03 series (wet adhesion of C1-class tyres in worn state with buffed SRTTworn) transitional provisions draft WT-25-04
30 Aug 2021 Worn tyres working group revised terms of reference proposal WT-25-05
31 Aug 2021 Minutes of the 25th Worn Tyres working group session WT-25-02
7 Sep 2021 Agenda for the 26th Worn Tyres working group session WT-26-01
7 Sep 2021 Worn Tyres Post Processing task force report to the Worn Tyres working group WT-26-02
7 Sep 2021 UN R117: 03 series (wet adhesion of C1-class tyres in worn state with buffed SRTTworn) transitional provisions draft WT-25-04/Rev.1
8 Sep 2021 UN R117: Proposal to amend document GRBP/2021/12 WT-26-04
8 Sep 2021 UN R117: Proposal to amend document GRBP/2021/12 WT-26-03
9 Sep 2021 Minutes of the 26th Worn Tyres working group session WT-26-07
9 Sep 2021 Attendance list from the 26th Worn Tyres working group session WT-26-05
9 Sep 2021 Worn Tyres working group planning schedule WT-26-06
9 Sep 2021 Proposal for amendments to the Worn Tyres working group terms of reference WT-26-08
9 Sep 2021 Agenda for the 27th Worn Tyres working group session WT-27-01
10 Sep 2021 Worn Tyres working group draft status report WT-27-02
10 Sep 2021 UN R117: Amendments to document GRBP/2021/12 WT-27-03
11 Sep 2021 UN R117: Proposal for amendments to GRBP/2021/12 WT-27-07
11 Sep 2021 Attendance list from the 27th Worn Tyres working group session WT-27-04
11 Sep 2021 Worn Tyres working group status report to GRBP WT-27-06
11 Sep 2021 Minutes of the 27th Worn Tyres working group session WT-27-05
11 Sep 2021 Agenda for the 28th Worn Tyres working group session WT-28-01
14 Sep 2021 Proposal for revised Worn Tyres working group terms of reference WT-28-03
16 Sep 2021 Attendance list from the 28th Worn Tyres working group session WT-28-04
17 Sep 2021 Worn tyres: New proposal C1 WGI @ Worn Molded SRTT WT-28-02/Rev.1
8 Nov 2021 Agenda for the 29th Worn Tyres working group session WT-29-01/Rev.1
8 Nov 2021 Worn tyres: Position on ETRTO Proposal for Correction Equations (Revision 2) WT-29-02
8 Nov 2021 Worn Wet Grip Index Equation and Coefficients WT-29-03
8 Nov 2021 Worn Tyre Post Processing task force status report WT-29-04
16 Nov 2021 Attendance list from the 29th Worn Tyres informal group session WT-29-05
16 Nov 2021 Minutes of the 29th Worn Tyres informal group session WT-29-06
24 Nov 2021 Minutes of the 28th Worn Tyres working group session WT-28-05/Rev.1
26 Nov 2021 Wet Grip on Worn C1 tyres: Threshold definition approach considerations WT-30-02
26 Nov 2021 Agenda for the 30th Worn Tyres informal group session WT-30-01
30 Nov 2021 Attendance list from the 30th Worn Tyres informal group session WT-30-03
30 Nov 2021 Worn tyres: Additional test campaign and necessary quantity of "molded SRTT worn" WT-30-04
2 Dec 2021 Agenda for 3 December 2021 Worn Tyres informal group follow-up discussion WT-30-08
3 Dec 2021 Proposal for additional Worn Tyres group test campaign WT-30-06
3 Dec 2021 Worn Tyres: Proposal for SRTT evaluation workplan WT-30-07
7 Dec 2021 Minutes of the 30th Worn Tyres informal group session WT-30-05
7 Dec 2021 Attendance list from the follow-up to the 30th Worn Tyres informal group session WT-30-09
8 Dec 2021 Minutes from the follow-up to the 30th Worn Tyres informal group session WT-30-10
8 Dec 2021 Proposal for Worn Tyres additional test campaign for minimum assessment WT-30-11
13 Dec 2021 Agenda for the 31st Worn Tyres working group session WT-31-01
21 Dec 2021 Minutes of the 31st Worn Tyres informal group session WT-31-04
21 Dec 2021 Attendance list from the 31st Worn Tyres informal group session WT-31-02
21 Dec 2021 Worn tyres: Proposal for additional text campaign for minimum assessment WT-31-03