Good discussion here, not much to add.
One thing to note that many seem to forget is that a 35" tire rarely measures thirty-five inches, and even if it did, after a season or two it will be closer to 34". When I sold my old 35x12.50x15 MTR (original-style) that had about 35-40% tread left, they measured 33.5" mounted on my truck.
How I look at this is for the future:
If you do NOT have any plans for going over 35" tires, then I'd recommend 4.88:1 for the above size discrepancy reason.
If you're unsure or do have plans to run 37" or taller, than I'd recommend 5.29:1. To run 4.88s now only to regear to 5.29s in two years is a big expense down the road.
I built a nice
Engine RPM and Truck Speed Calculator on our R&P page: https://www.marlincrawler.com/differential/ring-pinion Plug in some numbers, write down the resultants, and then go drive your truck how it sits now and compare. See if the RPMs vs speed is what you're looking for. If the calculator calls for 3,500 RPM for 65 MPH on the freeway then run your truck in 4th gear at 65 MPH to see if those high of RPMs is something you'd want to live with.... etc.
Tips:
Use your cell phone or actual GPS device to make sure you'll getting accurate speed reading.
Measure your tire height right now and use that number (or close to it) in the calculator. If you're sit'n on 33s now I wouldn't be surprised if they only measure 32".
Regards,
BigMike
