i just recently replaced my crappy 18" custom wheels with some stock 17 inch navigator wheels...

however i cannot get the centercaps on the wheels..

my navigator is a 1999 and the wheels are off a 2000 or 2001... i got them on ebay...
why will they not fit???

do i need to change my studs to 14 mm studs or do i already have the 14 mm studs..... should i buy a set of lug nuts from a 2000 navigator... will that hold them...

or will a set of 99 centercaps fit on the wheels????