265-75-16 vs 235-85-16 Tires

[DougC]

1997 F-250 7.3, Extra Cab, Long Bed, 4x4

I need new tires for my truck. It now has 265-75-16's. The tire shop suggested putting the stock size back on which was 235-85-16. What will be the differences in handling, fuel economy, etc. between these two sizes? I'm using the truck for towing a 6800 pound trailer, camping, and steelhead fishing. Most of my driving is on paved roads, but I do use the truck on dirt roads sometimes for fishing. We don't get much snow around here, just a few inches once in a while. I doubt the truck will ever see more than a foot of snow. The truck is completely stock except for the 265-75-16 tires that are on there now. I plan to keep it basically stock. I don't use the truck for offroading at all. Most of the time it's on pavement.

Any suggestions about tire size or tire brands would be really appreciated.

[Karls03]

The only real difference is that the 235 is going to be about an inch thinner than the 265. The difference in aspect ratio is why they are more or less the same diameter.

[countryraised]

235's are almost always .5 or more taller, at least that I have seen... being narrow leads to less rolling resistance and could help your fuel economy.

[DougC]

Thanks. The height difference is very small. I'm mainly trying to learn about the handling differences I should expect with the F-250. Sometimes I'll be towing 7000 pounds on pavement. I will also be using the truck to access rivers and lakes to fish. I'm trying to figure out which size tire to buy for a multiple-use truck. I want to avoid spending $1000 or more for the wrong tire.

[Karls03]

Here's how it breaks down, metric to SAE tire sizes:
265/75-16 = 31.65 X 10.43
235/85-16 = 31.73 x 9.25

You can round these up or down any way you want, but that's the EXACT conversion. Given the weight your carrying, I'd do the 265 for the extra width. Depending on how often you tow, I'd consider an E rated tire, too.