I am just about to start doing this exercise so I will see how it goes for me. I know it’s a while since you commented, but what I would recommend is to download some photos of wheels from the front and also of the thread, and set them as the background image (in object mode press N and it’s at the bottom). You can see the image only in orthographic mode. Then just model one segment of it over the image and duplicate it with the modifiers. Maybe if you’re stuck find a really simple wheel.
