You can use RIT dye found in most stores in the laundry section. I would recommend using a large coffee can and doing your dying in that. Bring the water and dye to a boil, hang your tires in the dye by a piece of stiff wire or coat hanger. just do not let the wire touch where you want to dye, use the axle hole only. Boil them until you get the depth of color that you want, let them cool and rinse with cold water. You can save the dye for further use but it will not be as strong as the first time. Hope this helps.

There is a good vid on you tube showing this process. I think it was posted by a guy called squrilrod.

ya that vid was made by squirrel. he runs a forum called "the toyz.com" he has a ton of how to vids. very usefull. i have been a member since this winter he releases a new vid every friday.