The manual isn't very clear about this. There is an o-ring that goes on the wheel hub and the cap slides down on it, sounds easy to me but the hub cap is too loose, it spins on the wheel hub.
Thanks for the info. I've done it all and it's still loose. I pulled it off my old wheel and it was very tight. Put it on the new wheel and for some reason it just spins on the hub. I'm going down to do do some measuring.