I really don't know the answer but I can take a guess. The standard adapter has a slight problem slipping on the hub no matter how tight you tighten it. The HD might be a little wider, or may have knurling on the inside surface to grab the hub a little better. Maybe it comes with golf shoes.
It's not a big problem on my 50 but I can see how it might be on a 80.
It's not a big problem on my 50 but I can see how it might be on a 80.
