5 inch Azusa Tri star front wheel clearance

[Brian Smith]

OK, so now a new problem. My Rupp Super K had steel 4" wheels on it when I got it. I thought I would upgrade to 5" fronts to match my 6" rears.  Went to put them on tonight, and the wheels hit the bottom of the king pin nut before they bottom out on the spindle.  It looks like a 1/4-5/16 inch spacer would work and still give plenty of thread on the spindle.  Is this common with these wheels?  I did a forum search and found nothing. Should I be looking at different wheels?

Thanks in advance, you guys are always helpful.