Pile of Tires

Review of Weight Conversion Factors for Tires

The Authority has reviewed and consulted on the existing Registry Procedure that outlines the weight conversion factors for tires. The procedure addresses the term “calculated weight” in the Tires Regulation and how it is determined in relation to both new tire supply data and the collection and management of used tires.

The Authority hosted webinars and one-on-one meetings to walk through the procedure and discuss whether there is a need to change it and the options for changing it. After considering the feedback received during the consultation, we have concluded that changes to the existing procedure are not required at this time. We will continue to work with industry next year to gather data and monitor whether changes are necessary.

For tires supplied in 2019, producers can report on the:

For those producers for whom an existing weight conversion factor does not produce a reasonable weight for collection target purposes and who will continue to report the tire units previously reported to OTS, Compliance Bulletin No. 3 – Supply Data Audits will continue to apply.


The weight conversion factors outlined in the procedure are based on the 18-category model established by Ontario Tire Stewardship (OTS) to allow producers to use their previously submitted tire supply data. Service providers (collectors, haulers, processors and retreaders) will also use weight conversion factors to determine the weight of used tires when they do not know the actual weight, and a weight conversion is permitted, as part of their annual reporting requirements, beginning in 2020. More detail on the annual reporting requirements is available in Compliance Bulletin No. 7 – Annual Reporting Requirements.

Since OTS’s Used Tire Program ended on December 31, 2018, along with the fact that the current conversion factors do not account for tires that were previously exempt, it was necessary to review the approach to determining calculated weight at this time. The Authority has posted a discussion paper further explaining the procedure and why a review was needed.

Development of Tire Supply Audit Procedure

Now that the review of the weight conversion factors is complete, the process to develop an audit procedure for new tire supply data is underway.

Currently, most producers are using tire supply data that was previously submitted to OTS – this data does not require producers to provide an audit report. However, 2018 is the last year that tire producers will have submitted supply data to OTS, meaning that data from 2019 and beyond will be new data, not previously submitted, and will require an audit report. It is important to note that 2018 data, along with 2017 and 2016, will be used to establish producer collection targets for 2020, whereas 2019 data will not be reported until 2021.

The purpose of the consultation currently underway is to gain feedback during the development of the procedure and to ensure that producers understand their tire supply audit requirements now, even though 2019 supply data will not be reported until 2021.