Ontario Tire Regulations

The province permits using tire chains when conditions warrant. In Ontario, studded winter tires are permitted between September 1st and May 31st for drivers in northern Ontario, which includes as Algoma, Cochrane, Kenora, Manitoulin, Nipissing, Parry Sound, Rainy River, Sudbury, Thunder Bay, and Temiskaming. Below these areas, the use of studded tires could incur a fine. In order to use studded tires, the driver must be a resident of Northern Ontario (north of Parry Sound and Nipissing districts), own a business in Northern Ontario, or have road authority having jurisdiction and control of a highway in Northern Ontario. Non-Ontario residents may use studded tires if the vehicle is in Ontario for no more than 30 days.

From there, Ontario has a list of regulations regarding size and placement of the studs. Essentially, studded tires are ok in Northern Ontario. A $1,000 fine can be handed out for using studded tires in Southern Ontario.

A tire,

(a) shall have no exposed cord;

(b) shall have no tread or sidewall cuts or snags deep enough to expose the cords;

(c) shall have no abnormal visible bump, bulge or knot; and

(d) other than a tire specifically designed for regrooving or recutting and marked as being so designed shall not be regrooved or recut. R.R.O. 1990, Reg. 625, s. 2. a tire shall not be worn to the extent that in any two adjacent major grooves at three equally spaced intervals around the circumference of the tire,

(a) the tread wear indicators contact the road; or

(b) less than 1.5 millimeters ( 1/16 inches in fraction ) of tread depth remains. R.R.O. 1990, Reg. 625, s. 3 (1).

https://www.ontario.ca/laws/statute/90h08

https://www.ontario.ca/laws/regulation/900625