This, I have no explanation for
Open garage door with the sun shining in, no prisms, no lens, not anything optical
I just happened to turn and saw the spectrum on the rim and kickstand
Closer fuzzy look
The only thing I did observe was blocking the sunlight from coming through the rear derailer made it disappear
Let the light through, and it appeared again
Me thinks Roy G Biv is playing mind games with me!