Abn150

Here's a link to an excellent utility that another member did a while ago.

https://www.f150forum.com/f82/traile...tility-244126/

Storeman

It would seem to me if you have to figure so close that so much as 2 or 300 pounds would make such a difference that a F250 my be a good idea.
I see a lot of really big TT behind F 150 trucks with a bed full and a cab full.
I am not a know it all on TT towing by any means. The largest I tow is a open deck car hauler 18 foot.

acadianbob

I'm curious as to what gear you wind up towing in with the 3.15's. 4th or 5th?

smokeywren

My normal trailer weight is around 5,000 pounds. With that trailer on long trips across the plains, the tranny is in 6th about 90 percent of the time. It will downshift to 5th for headwinds over about 30 MPH, and for any long hills over about 5% grade.

With my cargo trailer that grossed around 6,200 when I moved Darling Daughter from El Paso to the Oregon border on the Snake river, it was about the same on the plains, but because there are more steep grades across the Continental Divide, it was usually in 5th gear when climbing. It downshifted to 4th only a few times for the really steep grades, and with the cruise set on 62 MPH that was less than 3,000 RPM.

Dragging that 8,000-pound 5er across the hill country was a one-time deal that I don't expect to repeat. It was still in 6th gear around half the time. But any little headwind or upgrade would cause it to downshift into 5th. And because of the tranny calibration (software) programmed to prevent "hunting", in cruise control it wouldn't upshift back into 6th until I was going down a definite descent.

That EcoBoost engine is amasing. 45,000 miles now, with about half of that towing, so I'm pleased with everything but the 8 to 10 MPG when towing. I got better than that with my F-250 diesel. But I don't like being overloaded over the GVWR, so I'll probably order the max tow pkg next time to get the 500 pounds of extra payload capacity, and that comes with the 3.73 axle ratio. But I usually keep my pickups for at least 10 years, so it will probably be a few years before I order a new pickup.

I now know I should have ordered the max tow pkg when I ordered my F-150. Max tow includes the tow mirrors and integrated trailer brake controller I added, along with the 3.73 axle ratio I didn't want. But I expected the required 3.73 ratio to be way too short for unloaded cruising, resulting in poor MPG. But others with the 3.73 ratio and EcoBoost engine claim to get about the same unloaded MPG as I get, so that was a mistake I made.

acadianbob

Wow that surprises me; and I have an Ecoboost as well. We tow at about 62 mph (about 1700 RPM). 5,500 lb RV trailer; and it stays in 6th pretty much all of the time. You must be down around 1,500 RPM at that speed. It's really amazing the torque that motor produces at low RPM.

When I tow on 55 mph 2-lane roads, I'll sometimes lock out 6th as the RPM is so low at 55 mph. Then it will want 5th on more modest hills. So, I'm surprised that you stay in 6th with 3.15's. That's great!

I don't think you made a mistake with 3.15's then. I get about 20.5 mpg at 65 mph; max tow and 3.73's; 4x4. Most people I talk to with 3.15's get better than that. I hear lots of 23 to 24 mpg from those guys. Probably not at 70 mph though.

I guess we kind of hijacked this thread! Glad you like your truck. It is an awesome motor for towing.

Wannafbody

I'd go with 3.31's or 3.55 for a heavy trailer. I really like my 3.55 for pulling from a dead stop.