lt265/70/17 upgrade to lt275/65/18 worthwhile

If you need the rear axle load capacity increase, by all means, do it. If not, well then there really is no reason to do it, unless you just like the look of 18's over 17's.

17" rims and tires are a dying breed. Their ratings have been going down. Chris

If you go to 275/70R18 it'll take you up to 3640 per tire.

I did basically the same. But went from 245/70/17 to 275/65/18. Worth it? Maybe maybe not. I put KO2s on and lost around 1-1.5 mpg across the board. I also feel like I lost a bit of power. Hard to tell but seat of the pants say maybe.
I went from Michelin ATs to a much more aggressive tread pattern so I'm thinking that's the issue. They're dynamite in the snow though. But for a DD and towing not so good. They look great.

Larger wheels/tires will always take a MPG hit. You have additional rotating mass due to the heavier wheel/tire combo, larger contact patch(more friction) and a more aggressive tread (more rolling friction). Add it all up and there is no overcoming physics...

The upside is with a larger contact patch you can run a much lower PSI when unloaded making for a more forgiving ride IMO.

And yes they will LOOK better!

Seems like a lot of money (new wheels and more expensive tires) to solve a problem that you DON'T have... But hey, its your money and choice...

To me, the only time you may want to do this is if you are interested in tires that are not offered in the current size you have, or if you just want to spruce-up your rig. You're not going to increase flotation since you have the same tire width. You will be slightly taller. So is there a tire or set of tires you're interested in not offered in your current 17" size?

Also, if you do order a new set of wheels, make sure you do the research on the wheel's carrying capacity in the lug pattern you will be purchasing. They do make wheels that are more for fashion than actually carrying anything (for trucks). This information is harder to come by and sometimes require actually calling the vendor.

Personally I was thinking of getting some wider 18" rims so I can sport a wider tire. OEM wheels are 8" wide and max out at a 295 profile tire for similar height tires. Rims also varied greatly in load capacity. I was interested in sizes between 305 and 315, namely for flotation over sand and load capacity. I decided to just stick with the stock tire size and see how an AT does on the beach versus going all-in on a wider set of rims if they're not really needed. I'll just try airing down and seeing how I do.

I just put on 275/65R18 on my Ram 1500. I actually downsized from 275/60R20 Tires. The 18's will be about .4 inches taller. Not sure how that will affect you and your gearing. I installed Michelin Defender LTX M/S

If you need the rear axle load capacity increase, by all means, do it. If not, well then there really is no reason to do it, unless you just like the look of 18's over 17's.

Don't really need to increase, but always feel better having lots of excess load capacity.

17" rims and tires are a dying breed. Their ratings have been going down. Chris

This is what I am seeing when looking around. I noticed some popular tires are no longer made in a 17.

If you go to 275/70R18 it'll take you up to 3640 per tire.

Unfortunately those will not fit a stock 2008 Silverado without lifting

Larger wheels/tires will always take a MPG hit. You have additional rotating mass due to the heavier wheel/tire combo, larger contact patch(more friction) and a more aggressive tread (more rolling friction). Add it all up and there is no overcoming physics...

The difference is very very small, less then a half inch if not mistaken. I am sure it will have some effect but assume pretty small.

Seems like a lot of money (new wheels and more expensive tires) to solve a problem that you DON'T have... But hey, its your money and choice...

I am actually looking at new take offs, and more available in 18s then 17s. So essentially can get barely used tires with new wheels for about the same price as new tires alone.

I just put on 275/65R18 on my Ram 1500. I actually downsized from 275/60R20 Tires. The 18's will be about .4 inches taller. Not sure how that will affect you and your gearing. I installed Michelin Defender LTX M/S

Gearing should not be an issue, that is a pretty small increase. Last duramax went from 245s to 265s which was over an inch and did not notice any changes at all other then speedo being off a little. I am looking at the Michelins also, that is pretty much the only tire I want to run.

Thank you everyone for the input. New tires was not really something I was expecting on this new to me truck. Unfortunately once I got the truck home noticed a decent size cut in the sidewall, then after searching for a replacement realized they were cheap Chinese tires. I will see where I can get the best deal and go with that, if it turns out I can find some new takeoffs in 18s will go that route. Worst case a new set of Michelins will be on order. I like the idea of new spiffy wheels but might not be the right time for that purchase...

I know this, we are dying to get back on the road again. Last truck started having engine problems and took us a while to find a good replacement. Tires was not something we were anticipating after such a large purchase, but that is the way things go sometimes. Happy RVing!

What's your RAWR? Unless it's more than 6390# you won't gain any rated carrying capacity.