Thanks
I will run the numbers tomorrow.

 

Assuming you have 3.73 rear gears in your truck.

The size can vary based on air pressure, but here are some quick reference numbers based on the RPM values you gave me.
The 60 and 65 numbers don't quite line up, but they appear to be true to the calculated size of 33.1" based on the 55 and 70 numbers.

I like the tires.

Speed - Gear - Tire Size - RPM


Keith

 

It's difficult to get accurate RPM readings without digital, tires were aired to 75psi Front, 65psi rear. Outside air temp was 90 degrees so I had put about 10 mi on towing 19K and then another 5mi when obtaining those rpms and speeds so I expect tire pressure had risen by 10 - 15 psi do to temp.

 

Bear in mind 3.55 is now the standard option for a 2017 dually. The 2017 uses identical rims and tire sizes to what the 2011-2016 generation did.

 

I have the 3:73 gears and I also pull a 19K 5er 39' Mobile Suites; took it out for a test run hitched up but could not really tell the difference in gearing, plan on taking a trip in Aug. which will put me into some steep mountains 6%.

 

Right, I think you will be totally fine. You have the 440/860 motor which should handle 19k just fine, even at the "simulated" 3.55 ratio you essentially have now with the larger tires. I was just saying a 2017 dually with the 3.55 axle is still rated to something like 27k lbs.

 

I wonder why they do that using 3.73 gears as a standard then drop them to 3.55 gear? Mileage or just getting rid of excessive gear stock?

 

My preference would have been 3.73 gears. But the only options were 3.55 and 4.10. Since I do a lot of highway driving, I took the 3.55 and lost 4k in maximum towing capacity. But so far, the 3.55 has been great. I think you're right...Ford figured with the extra 65lb-ft to play with they could offer that lower gear ratio. On the other hand, it is a brand new axle (Dana M300) compared to the old axle (Dana 80 / S110, not sure) so maybe it was a Dana limitation for that axle.

 

1st loaded trip out on Toyo 255/80/17 Open Country AT 2.
I took the rig out for a longer loaded haul from SoCal to the Eastern Sierras and the handling change is impressive over the stock General tires, much more stable on the road; as far as the gearing change from taller tires barely noticeable. If you are thinking of a similar change of tires I say do it sooner than later, my Generals had at least another 5K of tread left (29K) but after I removed them and really started inspecting them closer they were cracking in the bottom of the tread on 2 year old tires. Lucky no blow outs as I had just returned from a 2500 mi. trip towing.

 

Good to hear. I'm at a crossroads with mine right now. The fronts are getting tore up on the edges, backs still look new. Debating if I should move the fronts to the rear inners, rear inners to the front, and align it, or just let it eat the fronts up. Starting to see some cracking so not sure i really want to put any money I to them at this point.

Having 4 worn out would make the upgrade easier to swallow though. I really want the bigger tire.

 

I would upgrade since you have cracking and with winter coming on sounds like a good time to me. JMO

 

Superduty450, now that you've had these about a year, are you still happy? Wearing ok? I'm just about at the end of the line with my stockers and its decision time very soon.

 

So far I'm still satisfied with the Toyo's, not a lot of miles but wear is fine and even, handling is a lot more stable than stock even towing 19K 5th wheel. I would do again when the need arises.The ride is smooth and quiet, tires are balanced with Equal balancing beads, no weights.

 

Superduty450, are you still satisfied with the Toyo 255/80r17? I have a 2012 450 that I am getting ready to replace the tires, Would like to go a little taller? Have you had any issues hauling? I have a 24k gooseneck horse trailer I haul quite a bit.

thanks for your help

matt

 

Still like them they, are no issue towing heavy. Just keep the fronts rotated side to side every 5-7500K