Not sure if it has changed but a few years ago when I used to dump old tires, I used to bring them to the Peel community recycling center. It was free to dump a few tires a day, if you had more there was a small charge for each tire over the daily limit. The people were cool though since motorcycle tires are generally smaller then car or truck tires, they let me get in a few more per day for free. It was also just down the road from my shop, so it was not a big deal to go by and dump tires every few days on my way home from the shop....
Im not sure if we can still do this?