Yes, rust convertor works… to a point. Follow directions. Wire wheel the steel wheel a bit. Scrub clean the tire and wheel with dish soap and water. Let dry a while standing upright. Mask the tire with tape or it will look like a Bozo-mobile when you are done. Trust me on this.
If you paint afterwards I’d suggest semi-gloss black, “bar-b-que” black or “chassis black” paint. I think flat black looks odd and most chassis parts are not flat black.