Work Item
ASTM WK90699
Revision of F3675-23 Standard Specification for 225/45R17 94H XL Radial Standard Reference Test Tire
Rationale
1) Paragraph 1.1: Following additional abrasion testing during 2023, the UNECE Task Force for Tyre Abrasion (TFTA) determined that snow tires (M+S non 3PMSF) should be tested using the Winter SRTT reference (F3675) and not the Summer SRTT (F3676) as originally thought. This applies to Special Use tires as well. The scope of usage of F3676 and F3675 is being updated accordingly.
2) Paragraphs 2.1, 5.4 & 9.1 / 9.2 / 9.3: due to the urgent need for official references for abrasion testing, F3676 was developed in 2023 by copying the model of F2493 (Passenger car tire model). Static physical properties were used, as they have historically been used for F2493 and it’s 14” predecessor.
As F3675 is now entering its commercial phase, while keeping the same tread compound, we propose to change to dynamic physical properties (tangent delta and shear modulus G*) and their corresponding measurement methods. These properties have been chosen because they can characterize more accurately the abrasion performance which is the key reason to develop this standard. The static physical properties are not as reliable to characterize this abrasion performance. As a reminder, a similar switch from static to dynamic properties was proposed, balloted, and approved in 2023 for the C3 SRTTs to better characterize their main performance (wet and snow in that case). And same as for these C3 SRTTs, a note is added to clarify that these dynamic properties are pre-production quality controls for the tire tread compound, not usable on a cure tire sample.
3) Paragraph 5.4: Update to the durometer hardness target. Reflects measurements on actual siped cured tire tread instead of un-sipped cured rubber sample.
4) Paragraph 9.4: Michelin Europe is not using the same type of durometer as used in the US. It is proposed to align the test method description for tire tread hardness with what has been historically used for the C3 SRTTs. This proposed description encompasses different durometer models (including digital in addition to the historical analog devices).
Work Item Status
Date Initiated: 05-09-2024
Technical Contact: Dominique Josson