For the bobbin winder tire, I used used sew classic for my singer 28, because that was one of the models listed. I could not get that small tire around my bigger bobbin wheel! So I emailed for suggestions. As others have said, customer service is great! She sent me links to old parts catalogs that helped me see that I had a larger variant on the bobbin winder. Then she suggested heat to stretch the tire. I soaked the tire in a glass of almost boiling water for a couple minutes and it stretched right over the wheel! It works perfectly, so if you encounter the same issue with the standard bobbin tire, try heat.