Same problem, and same single connection in center.
There are more than one type of rear tire for the XT1 and XT2(which I have, but same problem).
XT1 product range from CubCadet.com
View attachment 38905
(Only higher end ST & GT has the 4 bolt rear wheels)
XT2 product range
View attachment 38906
(Only higher end SLX & GX has 4 bolt rear wheels)
Google Image search, "Cub Cadet XT1"
View attachment 38907