i tried the golf cart hub caps, and they did not fit, like you said the hub sticks out to far,, i have bearing buddys on my trailer, that maybe the reason, warmbiker, good luck,
i used mobile 1 20/50 in my 1999 valkyrie for 10yrs, it was by far the best oil for that engine, never had a bit of trouble, i am now using it in my 2006 RSTD with great results, this is only my opinion, i love mobile 1, thanks guys, warmbiker,