Ever since the first custom rims we made made we felt like there was something not quite right about the designes. When you compare one of the wheels for the lego moc's to the real life counterparts you will see that the middle of the lego rim is way bigger then it should. This is because of the way lego attatches its wheels to the brake disc. It uses three pins and a large cillindrical shape. Because of this there is less space for a good looking brake disc. And the main limitation of the designes was the middle part where the spokes come together.
Our new wheel design works due to a newly custom brake disc which does not feature the three pins. Instead it has one square with a thread on top. The rim slides over the thread and the square blocks it from rotating. Then you screw on the locknut and voilá, your wheel is installed. There are also multiple locknut designs so you can mix and match the rims with locknuts. Some locknuts also feature a spot where a lego 1x1 tile can be placed.