Looking to purchase a Doughnut Type Spare Tire for a 2005 CTSV. I do not know the Bolt Pattern for the Wheel but the Wheel should be a 6 Bolt Wheel and a 18 Inch Tire. The car did not come with a spare tire. I saw a Cadillac SRT-V8 with 18 inch Wheels on it and it had a 18 Inch Doughnut Type Spare wheel and Tire underneath the Rear Body and the Wheel had 6 Holes. I don't know if the bolt pattern is the same.