Stock oem tire Brand,2017 Yukon Denali

[bob3700]

My 2017 Yukon Denali with 23000 mls has 4Continental 20 inch tires. The spare is the same size but a Brand new Firestone tire. What was the orig oem brand of tire on this truck?
Why would the truck have a different brand of spare tire.
Just bought the truck used from a GMC dealer.

 

[Blueinterceptor]

The continentals were the oem Tires on the 20” wheels. Alenzas on the 22” rims and a Michelin on the 18” rims. The spare tire brand is inconsequential as the spare was a different size and intended for temp use