I have a '66 monaco I have 5 wheels 4 are black and one is blue- appear to be original- I was told the blue one was the spare and was different width than the regular wheels is this true?? anyone...and if so what are the widths for black and the blue one??

I would guess the car had full wheel covers, hence the black wheels rather than body color. I would also guess that if the spare is blue, it's the same color as the car. As to width differences, never heard of that.

While the color of the rim on the spare tire was many times different, in every case I have seen, the width always matched.