Skins Rim recolouring?

[Koeiss]

I downloaded Wack's 1991 CRX and the stock rims are a sort of dark gray colour. I wanted to change it to make them white, like the CRX that a family friend had, but I have been stumped by this. I have exported the wheel_lod0.png from the txdiffuse section in the CM Showroom, but I have had trouble recolouring it as the texture is not solid single colour. I am not experienced in GIMP so I do not quite know how to go about changing this without replacing it with a single solid colour.

 

[NightEye87]

In GIMP or Paint.NET you can probably make a new layer with the colour you want and set the 'mode' to multiply/overlay/etc.