Hi guys I have a 2015 Silverado 1500 and I have a question about the spare. I got a flat the other day and when I went to put the spare on, I discovered the factory spare is a different size. The dealer is telling me it is okay to run on the spare even when carrying a load in 4WD. I just wanted to get a second (or third) opinion if this is going to hurt the truck in any way. The truck has P265/65R18. The spare is P275/70R17. My understanding is they are the same diameter so should be fine.
Any thoughts?
Thanks
Jenny

 

Check the tire size on a chart like at Tire Rack. The tire revolutions are the same, so they are essentially the same tire though different rim size. The spare just has little taller side wall. Have the same kind of deal with my 2500 pickup spare. 18" on regular wheels, 17" spare. I checked out the tire sizes and they are the same revolutions per mile and same load capacity.

 

Thanks! I will look at tire rack, appreciate the feedback

 

check the tire placard. it will list both spare & service tire size from factory.