try making a new layer, filling the selection with a color, resizing that, make selection of image on layer. only way i know how.

and here is the gun metal grey rims.

 

Well, you CAN resize the circle marquee by clicking on the "arrow" tool next to the marquee tool....which will bring up your transform dimensions. Just do that, and make a new layer that has nothing on it, and resize it on that layer.

You know what I mean?

 

thats too much work, by the time i do all that i can just as easily just reselect the area at the precise size i need

 

Your the one who asked how to do it

And yes, just reselect, its much easier.