Thanks for the detailed response, and not taking it the wrong way. It's really hard to tell intent from purely text communications so I appreciate the benefit of the doubt. It's crazy you're MPG is that good so I'm pretty impressed to say the least. The Tundra is a bit long in the tooth, or was, and the mpg was one of the major downsides, but considering all things I feel like it's not as bad as I expected. It's not great by any means, but I honestly expected worse.Well, I probably shouldn't have termed it that way. My front axle WR is 4,000Lbs front and 4,150 rear. My loaded weight front was 3829 front and 3860 rear. I agree, it's not meaningful, and in fact not good if a vehicle is overweight one axle but under the combined and you convince yourself it's OK.
I also agree the whole payload dance, both by drivers and by auto makers is comical. It's really hard to pin down. I DO have a problem going over, and would rather not be, but as long as I'm in the margin of the AWRs and can pare the GVWR back a bit I'm OK with it. I specifically researched all sorts of vehicles and chose the Tundra for the combination of size, comfort, driveablity, and ruggedness. I like that it has 10.5 rear diff and axle from Toyota's Hino 3/4 ton commercial trucks, though just semi-float. I know all the arguments on "you can't increase payload" and have no desire to rehash them, but given tires with far more capability, stronger wheels, and stronger springs all compared to stock, along with Toyota's engineering margins, as well as being under both AWRs, I'm fine with where I'm at. When I was hot on a FWC, the only consideration for me was a 3/4 ton, but with the lighter camper, I liked the Tundra better.
As to MPG, I do hand calculate it. I use TFL Trucks method of auto pump shut off, wait 30 seconds and give it one click. When I was regeared, they installed a Hypertech speedo calibration. I checked it with a Bad Elf GPS (used a lot in aviation) over several 100 mile routes as we have traveled. My stock Tundra tires were rated at 648 revolutions per mile, my Coopers are 611 a 5.7% difference. The Hypertech is not perfect and got it down to a 3.8% difference, GPS checked. I corrected my miles by that and got the 14.2.
FWIW, bone stock and empty with just me and my wife driving from South Phoenix to Flagstaff -- an hour of flatish highway, then mixed steep uphill, but some big downs too -- we got near 17 without the camper. We picked up the camper and got 16 on the trip back -- more downhill but less aerodynamic with the camper. On two trips to SoCal with the camper and truck in different stages of build and not fully loaded we got low 15 mpg. HOWEVER, I don't drive like your grandpa. I drive like your great great grandpa. I accelerate really slowly and only go 65 mph with the camper. I use every hypermile-ing trick in book, including coasting on any downhill I can and being willing to slow further going up hill. Pre-regearing, I was getting in the 13 to 14 range. I haven't had enough trips with the regear to know where it'll come out, but my seat of the pants feel is that it offsets the tire size change very well, and some of the weight. The big camper problem is the aero drag hence only going 65. Don't get behind me on the highway!
BTW, in my experience, when someone says "I'm not calling you a _______" most people tend to think that's exactly what they're doing. But don't worry. I'm not offended and I'm not calling you a [fill in the blank]
I'm not trying to tout the Tundra or 1/2 tons or brag about anything, just wanted to give a fellow Ovrlnd camper owner some feedback on my experiences and this was the forum he posted in.
I also won't get too into the whole GVWR dance and all that but to say I agree with everything you said.