I put 18" wheels on my new 4x4 GMC sierra and have only a 17 inch spare?

[Richard]

will this work if i get a flat,or will it cause a problem? Tire size is LT 275-65R18 and spare is P265-65R17

this is a new truck and came from the dealer like that,what should i do!

[Humveetech]

It will cause a problem. I suggest you go buy a cheap rim with tire on it from the junk yard & stick it in the place of the other spare

[Sarah]

You can't change the tire. It is either an oversight with the dealership or if you bought it from someone they had it wrong. Cars can use a donut ....if your spare had a rim in it you can use it but if no rim is in it it won't fit on an 18". I would take it back and get a full size spare.