Strange Spare Tire Situation

[wyosteve]

Ok, I bought my 2015 3500 SRW new and it came with 285/60/20 tires and 20 in. wheels (obviously!). Never had a flat or any reason to pull the spare. Today I'm putting on my winter wheels/tires and happen to glance at the spare. It is a 275/70/18!! Spare has never left the carrier. So my question to those of you who might have the 20 in. wheels, is whether you also have an 18 in. spare and different tire size. Don't know if FCA did that because a 20 in. might not fit the carrier or if the dealer might have switched out the spare before I purchased the truck.

 

[Badunit]

Yes, that is the correct spare. The diameter of the spare tire is the roughly the same as the stock tires on the stock 20" rims.
Diameter of 285/60R20 = 33.5" nominally.
Diameter of 275/70R18 = 33.2" nominally

 

[wyosteve]

Thanks Badunit. I kind of thought that might be the case, but it's good to have it confirmed.