Can you stretch the bobbin winder tire?
 

I just got the largest tire I could at Sew Classic. It looks like the right size for my Pfaff 11 but I am having a beast of a time getting it on! Does anyone know if they can be safely stretched temporarily? I am thinking maybe a soak in warm water or light heat from a hair dryer? I would just go ahead and try it but I am worried I will mutilate it or tear it in my attempts. Maybe I should just cut it and re-glue with something once I have it on?

Try boiling it. It works on other plastics and rubbers.
Rodney

I tried hot water (not boiled) but that didn't do much at all. Then I stretched it over a screwdriver handle by pushing it onto the side that was tapered. I used a hair dryer to warm it and left it on to stretch for a few minutes. Then I quickly took it off the screwdriver and rolled it onto the winder wheel. Phew! It's on!

Good for you, mother of invention.

I've had to fight a few German machines to get them to accept bobbin winder tires too. ;) The tires do stretch some as they go on, as you found but it can be pretty tense during. Especially if you've ever had a bobbin winder come apart in your hands in the past!

Don't try to force it. Try to roll it on.