We want your feedback on a potential amendment to Technical Standard Document (TSD) 139, New Radial Ply Tires for Motor Vehicles With a GVWR of 4 536 kg or Less. This amendment is based on comments from the winter tire consultation, which closed on February 18, 2025.
Manufacturers noted a problem with the endurance test requirements for passenger car tires. The test involves mounting the tire on a test rim and inflating to the tire's specified pressure. One of the ways a tire can fail is called "tire chunking," where a piece of tread comes off the tire.
Manufacturers said that, for a particular case, this failure doesn’t tell us the strength of winter tires. It’s actually Parasitic Tread Block Chucking (PTBC) caused by the winter tire reaching a much higher temperature in the test than it would in real world use. Manufacturers report that this type of test failure is stopping them from importing better performing winter tires to the Canadian market.
Manufacturers gave enough justification in the previous consultation for Transport Canada to change TSD 139 to accommodate this case for winter tires. The change adds the definition of PTBC to TSD 139 as a non-failure mode. This definition matches international standards. Normal tire chunking is still a valid failure mode.
We’ll also have a 6-month transitional period for this change. This means manufacturers can follow the previous version or the amended version of TSD 139 for 6 months after the amendment is published. After 6 months, the amended version is mandatory.
Reference documents
Request a copy
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Proposed TSD 139Request a copy - Proposed TSD 139How to participate
- Read our background information
- Please submit your comments by email: RegulationsClerk-ASFB-Commisauxreglements@tc.gc.ca. Include “Consultation - Update to TSD 139 PTBC” in the subject line.
Related information
- Forward Regulatory Plan: 2025 to 2027
- Amending the Winter Tire Regulations
- Motor Vehicle Safety Regulations
- Motor Vehicle Tire Safety Regulations
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Transport Canada
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Email: RegulationsClerk-ASFB-Commisauxreglements@tc.gc.ca
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