2019 Silverado, will probably need tires later this year, just doing some checking now. Has 265/65R/18s thinking of going to 285s or maybe a 275/70R.
Truck is getting a 2 inch lift at dealer next week and figure a little bigger tire would give me just a bit more clearance.
Like my Chevy but they seem a bit lower than other trucks, and already smashed one sidestep nerf bar on a high curb. Not a serious off roader but some places I go (farms, poor dirt roads/ mud ruts and such) is cutting it a bit close right now.
So I'm sure some on here have done this, any recommendations on which way to go?

While I don't have a Silverado, I have often bumped up one tire size on 4wd trucks when upgrading from the factory tires. This generally equates to an inch in height, more or less, and sometimes up to an inch in width. There has seldom been ill effects, except to lose a bit of fuel economy. Another item, which is also fairly important, is tire construction. Going from a P-metric to a similar tire that is an inch taller will generally only add a couple of pounds of rotating mass to go along with the lower effective gearing due to the increased diameter. It's often not much of a hit in handling/power/braking/mpg loss. But when you combine a heavier LT construction with the larger size, the weight and diameter combination can result in a more noticeable difference in driving characteristics. Just something to bear in mind. Many factory equipment tires are built toward the lightweight end of the spectrum for better ride quality and MPG, plus they are cheaper.

Yeah, I figure the factory ones were as cheap as possible to maximize profit. Not bad tires but could be better, considering what a truck costs. The 285s I looked at are about 3/4 inch wider and about an inch taller. Leaning toward those. I realize it will also throw my speedometer off a bit but probably not enough to worry about.

Changing tire size didn't effect mileage all that much, but you do need to factor in the new tire size since speedometer and odometer will read less than actually miles/speed traveled with larger diameter tires....

For me it was/is 8%.....

https://tiresize.com/speedometer-calibration/

I'm going to run it for a while with the 2" lift and see how it is, might be all I need, but I'm still thinking larger tire partly because I like the look.

A lift alone won’t give you more clearance under the axles without also adding a larger tire. You may save your side steps, but your primary reason to lift is to put bigger tires under it. I think a lift on stock tires will look strange. I would advocate the biggest tire with the smallest (or no) lift. I’m not sure of the new body style, but you could shoehorn bigger tires on a stock truck with some minor fender and plastic modifications.

I swapped just the opposite. I went from 265x70x17 to 245x75x17. Same height and rating but 1" narrower. They handle better on slick roads and allow heavier chains on the fron.

I swapped just the opposite. I went from 265x70x17 to 245x75x17. Same height and rating but 1" narrower. They handle better on slick roads and allow heavier chains on the front. All wider tires are good for is sand and we don't have much here.

And I'm gathering from the owners manual that the different size spare doesn't matter as long as you stay in 2WD stay under 70 or if pulling a trailer 55. The current spare is a 17 (18s on truck) and a 70R (65R on truck)

Your going to add a lift to your truck and then keep the little 31" tires on it?

Just until I need new ones probably by the fall, and it's only 2". (but that's what she said)

I like to run one size over stock - on my Dodge 2500 it's 285/70-17 vs 265's. I recently bought a '16 Chevy 3500 and it has 275/70-18's on it which I believe are one size over the stock 265's. Previous owner also put on after market wheels that are wider with more offset which was causing some tire rubbing in the front fender wells. I had the front torsion bars adjusted to raise the front 1.25" and everything seems to fit pretty well. I'm not sold on the wider wheels and would prefer the stock wheel size, but it seems to be working fine other than slinging chit all over the side of the truck when it's sloppy out...