Not many people have seen the red rimmed but I remember seeing a picture of the first Oliver 550's off the line and they all had red rear rims. I remember also reading about the company upating the super 55's with the new sheet metal to the 550. This would explain the first 550's having 144 cubes and red rear rims which the super 55's had. I am trying to find out at what serial the super 55 inventory was cleared and the 155 cube engine was adopted. That may coincide with the change to white rear rims.  There is a picture of another 1958  550 with red rear rims at the other forum in the photo area. It is pulling at a fair and owned by a Troy L in Oregon. I have seen a few others also. I did see in my owners manual that the power adjust wheels were not red only the regular wheels. There may also be differences between HC(gas) tractors and diesels if they were assembled at different plants. Please send info on serials if you have them. Thanks