From the online order guide, here are the official wheels available for the 2009 Traverse:
NX7 - 17" x 7.5" (43.2 cm x 19.1 cm) steel
QS6 - 18" x 7.5" (45.7 cm x 19.1 cm) machined aluminum
RCM - 20" x 7.5" (50.8 cm x 19.1 cm) machined ultrabright aluminum
Source: http://eogld.ecomm.gm.com/NASApp/do...0&vehicleID=7175§ion=wheels&page=&butID=4



Source: http://eogld.ecomm.gm.com/NASApp/do...0&vehicleID=7175§ion=wheels&page=&butID=4