3.55’s are great… for diesels

 

Try it. It defaults back to the diesel engine.

 

If you can afford an Airstream and a new Superduty F-250, then give your drivetrain a break and choose the 4.30 gears. These trucks have some rather tall tires available.
Frankly, after spending around $200k on the pair, I don't think you really care if you are getting 8mpg vs 9mpg. You will get less hunting through the gears with a higher ratio.
Don't forget to add the Locking rear differential to your build. It's helped me greatly when pulling out my RV uphill after days of rain. Also, I upgrade to OFF ROAD tires vs ALL SEASON.
I removed my 18" Wrangler's and installed factory take offs Michelin 20" and they just don't hook up as good when towing through wet RV parks. The Centenial MT 33x12.5x20 work great.
In my opinion, Airstream RV's, to aid in aerodynamics, sit closer to the ground than other towable RV's. There will be dips in the road that it won't clear. What a drag, LOL.
I chose a Forrest Hills Wolfpack GOLD, 24PACK14 (31' length) Toy Hauler as it has ground clearance, tall ceilings and a flat roof that is solar panel friendly. I caught it on sale for under $19k in 2019.
I upgraded to a 14K Sway-A-Way hitch from the dealer installed 10K that was not rated to the RV's max 11.4K GVWR. No need for additional sway control now. My 6.7 barely knows it's there.
Don't forget to get two spare filled propane tanks as cold showers suck when you are camping primitive. Cooking on a campfire in rain sucks too. Be sure to lock them onto your truck bed.
If you plan to travel in cold weather, get a four-seasons rated RV. Might I suggest an F-350 vs the F-250 and add the Snowplow/Camper package? The F-350 has a higher capacity rear axle and springs.
With a 10k RV, the F-250 may have a saggy rear end. Also, dual batteries and on-board 2k watt power? Yes, very handy indeed.

Safe travels in your RV adventures! Enjoy your new truck and RV!

 

Give your drive train a break? Gear hunting? You don't even know.

 

Higher ratio = lower number (ex. 3.55)
Lower ratio = higher number (ex. 4.30)

 

I noticed this is very common in this forum. And usually it is people that type the 5 million word know it all rant posts.

 

I would go with the 4.30 gears for sure, no reason not to with the high overdrive gears of the 10 speed.

 

It's a two way street, with the extra low first and second gears of the 10 speed, there is no absolute need for 4.30 unless your goal is always staying in 10th when towing.

 

I don't even use 10th gear unless I'm over 50mph. I even lock out 9th & 10th unless I'm over 40mph. A gasser shouldn't be lugging along at 1000rpm....

 

What lugging? My 3.55 runs at 1600 RPM at 70mph. I have always had long legged gas Fords that run great at 1500-ish RPM, it's got enough torque north of 1k rpm that see it propelling the truck along leisurely doesn't bother me the slightest.

 

Not with my '22 F-350 SCLB 6.7L w/3.55, but certainly with older gas powered trucks that I've owned. I'm very happy with what I have now. I would like a set of 4.10 for my Suburban K2500 instead of the 3.42 though. Try towing with a CVT if you like constant ratio changes, lol. Been there, fried that. $5k down the drain. Best of luck to y'all.

 

let's figure out the ratio of gas pumps your truck passes by versus filling up. 🙂

 

1st gear in the 10 speed is only 4.7:1 not really that low.

 

Why are you worried about my gas MPG? That is the absolute last thing on my mind when I drive my truck.

 

the first gear on the old 6 speed was 4:17:1. That means a 10R100 with 3.73 has first gear equivalent to 4.20 on the 6R100.

https://media.ford.com/content/dam/f...Tech-Specs.pdf

By that logic, since the highest ratio offered with 6 speed gas F250 and F350 was 4.3, and a majority of them had 3.73, all ford gas trucks should be dead by the side of the road from tranny blowing up from gear hunting and 6.2 gas motors dying from constantly being lugged. At the very least ford owners hould have made a class action lawsuit against to Ford that their 3.73 6.2 trucks were totally undriveable and 4.30 6.2 trucks were BARELY adequate.

So either ford trucks have been dying left and right and we just don't know about it, or that the 4.30 imperative upheld as gospel by a small group of users is mostly based on conjecture and preconceived notions, and perhaps, just perhaps, users' own confirmation bias.