I have possibly the biggest dork disc ever on my 72 Schwinn Sports Tourer. It's 9 inches in diameter and 28 inches in circumference. It looks OK as there is a 34 skip tooth cog next to it. It also has a 54/36 chain ring. It is a project i have been working on as i got it for free. The frame is a little big so i may just get it running and sell it. I polished it and it sparkles as it is stainless steel. My Bianchi, OCR 3, Trek 330, World Sport are all DD free. My Trek 1400 and Gran Sport have the small plastic discs.