You don't mention a specific style wheel, but a cursory glance at the wheel site, pasted below, shows that most 19"
X5 wheels appear to be in the 45 front, 48 rear offset category.
Good wheel site; it's in German, but just use the drop down tabs and plug in
E53 or E 70, or...
Felgen-Katalog - BMW-Treff - der Treffpunkt für alle BMW-Fans und -Fahrer
GL,mD