So holy cow, right now I am low riding sagging in the back AND the front from suspension that has 180,000 miles on it, the stock p.o.s. heavy rusted steel 15's with the stock 225/75/15. I am planning on doing the tundra 5100 lift at 3in with toytec and ome springs. Also, I am buying some of the stock 16in alloy 3 split spoke wheels that I am gonna purrdy up, with 265/75/16's. I am also planning on having front and rear armor, and rock sliders. Will this be fine with the stock gearing?? Cause according to REVELC he has a hard time with the 3.4 on 32's, which I don't understand cause my Tacoma had the auto 3.4 with a 2in lift and 32's.There may be some other issues with your vehicle (or your driving style, no offence) if this is the case.
Going from the stock 265/70r16 to a 265/75r16 is simply not a big enough difference to warrant a regear or even notice much of a difference. You are going from a 30.6" tire to a 31.6" tire, giving a difference of 3.3%. A gear ratio of 4.23 would return you to the equivalent of 4.10's and the 265/70r16. Sure, the 265/75 will weigh slightly more than the stock 265/70, but again, it is so minimal that the difference would not be noticeable.
I ran 265/75r16's for over 2 years and am now on heavy 285/75r16 mud tires with lots of added vehicle weight in the form of armor, winch, etc. I did a wheeling trip on sunday with a full car - over 700lbs in passengers, as well as a full size spare, hilift jack, tools and some gear.
The truck is not fast, but its no slug either. I had no problem maintaining 80 mph on the highway even with all the mentioned weight. In fact, I find this gearing setup is actually quite ideal on the highway as I can maintain low rpm's and cruise along just fine in 5th gear. The only time I really want lower gearing is in the rocks. I run some fairly technical rocky trails (for ifs) and I will admit, the 4.10's and 33's is terrible in these situations and I am constantly riding the clutch to prevent stalling. That being said, I think I would feel the same way with the stock 31's and 4.10.
In short, I will be investing in a dual transfer case setup before re gearing my diffs. The lack of double low range is limiting me way more than the ifs and I know that 4.88's or 5.29's would be unbearable on the highway with 33's.
The need for regearing is seriosuly over hyped on this forum IMO. Go to any other yota forum and you'll see what I mean...
Another thing, I cannot figure out what trim my car is. I am now the 3rd owner of it. I always assumed it was base, with the 2.7 manual and steel 15's, but I noticed that no other bases that I see on here have the black fender flares, which I thought came on the sr5's. Anyone?