[matchsticklake]

Hey,

I just bought a new 2016 Sierra with 18s. The spare like most is a 17. I am looking to upgrade the tires to either 275/70R18 or 295/70R18. Any of you out there have experience with what spare I should run to match sizes properly. Flats are common for me as I work in the bush and cant risk running unmatched tire sizes. I am hoping to find something that I can fit underneath. Any advice would be appreciated!

 

[zachfletch573]

Try playing around on https://tiresize.com/converter/

But I do not know what size will fit under the truck.

 

[19trax95]

Honestly if flats are that common for you, then I wouldn't be keeping the spare underneath the truck. Just keep it in the bed so it's easy to get to

And I'd also just buy a cheap steel 18" wheel and get the same size tire you'll be running. That way there's no guessing if the diameters match or not.

 

[09chevyman]

Handy dandy tire size calculator here
http://www.discounttiredirect.com/direc ... ireMath.do

 

[esox07]

Honestly if flats are that common for you, then I wouldn't be keeping the spare underneath the truck. Just keep it in the bed so it's easy to get to

And I'd also just buy a cheap steel 18" wheel and get the same size tire you'll be running. That way there's no guessing if the diameters match or not.

I agree. Get an 18" rim and tire that is the same size as the 4 wheels. If it won't fit under neath, then put it in the bed. Basically, it won't matter if you have a 17" or 18" rim for the spare because if you try to match the tire diameter of the 4 wheels, it will be the same overall diameter whether 17" or 18" so to make it easy, just get an 18" and take the guess work out of it and any possible mismatch on tire size. Then see if it fits under and if not, put it in the bed.

 

[walker_etree]

I have stock 275/55/20's on the truck with a 265/65/17 as a spare underneath. I finally got a matching 275/55/20 for the spare & it fits under the truck fine. There isn't much room to go bigger but for stock tire sizes & rims it is fine.