What would the pros and cons be to changing my tire size on my 2013 GMC 2500HD diesel from an LT265/70R18 to an LT275/70R18? I'm looking at doing this due to cost only. I can get a very good price on the LT275 Goodyear tire. I know it will change my speedometer reading vs actual speed. I'm wondering about any hidden issues I haven't thought of. Thanks in advance!

My stock size is 275/70R18 and one thing I like about them is they seem to give me a lot of options because it's a popular size. I'm still running the stock junk but plan to stick with this size when they finally wear down enough. I ran oversize tires on my last rig for years and you get used to the speedo being off pretty quick. Just use a GPS or app on your phone to compare reality vs indicated speed and it'll be an automatic calculation in short order.One thing to consider is your spare. One if you can fit a larger size replacement, or two if you don't I'd be careful about going too far with the spare on the rear if you have limited slip.

Did you notice any change in MPG by running a larger tire?

There is a quarter inch of height different between the two and your speedometer will be off by about 1 mph at 65. Your stock tire rotates 618 times in a mile, the new size would rotate 608 times.Any difference in fuel economy would be more influenced by tire weight. I think the difference would be very minimal. For the price savings and wider selection of tires, I would make the change.

My guess is you'll notice no change. The two are only 1/2" different. That equates to 1/4" on the ground. That's no different than driving a brand new tire and one that's worn out.

only about 0.55" larger in diameter. probably will not notice a change

LT265 vs LT275 | Good Sam Community

ksss
Explorer
Dec 17, 2016
JustLabs wrote:
Greene728 wrote:
I myself doubt you'll see any changes at all. Especially with the Dmax.

He won't notice any difference. I replaced the junk OEM 265/70/18 Goodyears on my 2500HD with 275/70/18s shortly after I bought it.

At the time, there were exactly two different tires in the OEM 265 size to choose from. I went 275s to open up the tire choices.

I did the same thing for the same reasons. The 275's look better on the pickup than do the 265s, but the increase in tire options is the best reason to do the deal. I just put on a new set of Nitto EXO Grapplers. Really like that tire, especially in tough driving conditions. I was able to get 55k out of my last set and if it was going into Summer instead of Winter I could have pulled more mileage out of them. Pretty good for a tire that aggressive.
ksss
Explorer
Dec 17, 2016
rottidawg wrote:
Latviaman wrote:
I have 2012 3500 SRW and run the original 265 70 R18 most of the year. But I also have 275 70 R18 winter tires. My 275's rub the plastic wheel well behind the front tires if I turn sharply. My winter tires are studded Coopers. Hope this helps.

Bummer....I have the same truck only a 2500. I was planning on switching to the 275 size because of the greater selection of available tires. Is yours a 4wheel drive?

Hard to understand how a increase of only a 1/4" radius - 1/2" in diameter would rub. Anyone else having clearance issues on the 275 size on the GMs?

I put a Cognito Leveling kit on my 2012 2500HD and I never rubbed with 275 Nitto EXO Grapplers. I don't rub with the same leveling kit on 2015 3500 gas or Deisel.

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