Crazy Diamond's fist clashes with Ichigo's sword, Ichigo's sword gets reverted back into reishi, Ichigo turns into a normal human, Josuke pummels him, fight over.
True, I thought with getsuga he may have a chance but he could just punch and nulify that too. Also if my calculations are correct, Star Platinum is about 8 1/2 times the speed of light; The Hanged Man moved at light speed, Silver Chariot blitzed it making him at least 2x the speed of light (With his armor on) then Anubis took him over and doubled his speed and power making him about 4x light speed and Star Platinum beat him in both strength and speed, then he got up and powered up and doubled again to the point where Star Platinum was barley able to keep up but was still able to out do him by a little so then he would be around 8x the speed of light. Then when Jotaro fought Dio The World was stated to be even stronger and faster than Star Platinum until Jotaro learned to use it better and then he was able to out match Dio as well until he powered up by drinking Joseph's blood and even then Jotaro was able to keep up with him speed wise so that would be around 8 1/2x the speed of light. Josuke was ALMOST as fast as Star Platinum and by only a short margin. So I would clack Star Platinum at around 8 or 8 1/2x the speed of light plus his Star Finger move which is even faster. So Josuke would be at least 7 1/2 to 8x light speed. Going by feats. Still he does have a very limited range of only about 3 meters attack wise. Excluding he projectiles that he can use around the area.