Tires

What is the load capacity of each?

Depends what you are trying to accomplish . BTW I think you meant 235/85/16 . If they are both E rated they will have the same load rating . If you want a taller tire with higher weight rating a 265/75/16 would be a better fit . Same height as the 235 , a little wider than a 245 and 400# more capacity than either .

I went from the 245's to the 265's as ticki2 mentioned. My mpg lost 1 mpg.
Not a big deal , the extra load carry was worth a lot more to me.

I retire the older tires to the 5er... anything bigger then a 245 would drag on a shock. Yes I did mean 85 .... fat fingers and bi-focals.

I swapped out 245/17R for 285/17R tires to get an extra 1100 lbs. of load capacity at the rear. New tires are 1 inch larger in diameter when the truck is unloaded and this results in a 4% error with the odometer/speedometer reading or its being off by about 2 MPH or 1/2 MPG - both lower than actual.

With a 3000 lb. camper load in the bed the tires squat and my odometer and speedometer readings are more accurate with the new tires than with the factory supplied ones. In effect there is little or no change in the overall gearing for the truck.

It is odd how people can ignore the problems with tall 3.55 or 3.33 gears but worry about a 4% change in tire diameter. There is a 25% difference in performance between 3.73 and 4.10 gears in towing capacity and this is significant.