smokeywren

Not exactly. 2015-2018 HDPP F-150s with XL trim and 17" tires still come with LT275/70R17E tires. HDPP F-150s with XLT or Lariat trim and 18" tires now come with LT275/65R18C (load range C)

Velosprout

Yes, 2017 HDPP GVWR is 7850 lbs. 2014 HDPP GVWR is 8200 lbs.

2B1Ask1

I agree. We live in the foothills of the mountains in SC and go to the mountains often, especially when camping and glamping. We didn't "need" 4WD so spending the extra money, and losing the fuel economy every mile we drive, wasn't worth it to us. So, we went with the 2WD with electronic locking rear axle...and love it. It's all we need for towing, climbing, etc. when we go to the mountains and get, slightly, off road.

marshallr

A locking rear axle is a handicap in snow. It can be useful to get you moving if you're in a situation where one wheel is on dry pavement and the other is on ice/snow and all the power is going to the one wheel with no traction. But it should be disengaged as soon as you start moving. Driving with it locked on ice/snow is a good way to end up in the ditch quickly. Traction control is far more effective in ice/snow than locking diff's.

A 4X4 doesn't use any more fuel than a 4X2 unless 4X4 is engaged.

In the long term a 4X4 doesn't cost any more than a 4X2. You pay more up front, but it is worth more when the time comes to trade or sell. Even if you drive it until it is scrap metal a 4X4 will bring more. A fellow could live a lifetime driving 4X4 trucks and not spend any more money than a fellow who spent a lifetime driving 4X2 trucks.

jetjoe

You are correct about your first statement. I once knew a fellow who installed positraction on both of his 4WD axles. The first occasion of ice he couldn't keep it on the road. Just the crown of the pavement was enough to send it sideways. Traction control is simply the application of the spinning wheel brake to cause the differential to transfer power flow to the opposite wheel. It wouldn't work on a locking differential or well on a limited slip. And if used a lot, it's damn hard on brake pads. Had it, used it.

As for 4X4's not burning more fuel? I beg to differ. Unless the manufacturers have come up with something totally new in the last couple of years. Even when disengaged there is enough drag through the system to burn fuel. Try wrapping some rubber bands around the front drive shaft to something solid and see if they are still there after a short drive. If it turns its wasting fuel. With every 4 X 4 I've owned, I have always removed the gear inside of the hubs in the summer months. In the case of my last F250 SD, an immediate improvement of 2 MPG was always gained and those rubber bands were still there come winter. I used to do this to several friends 4 X 4's with similar gains. Also, you will notice that most if not all MPG ratings are lower for 4 X 4's. Just observe a jacked up 4 X 4 passing you by and look at the front drive shaft spinning away accomplishing nothing.

If for no other reason the extra weight carried is not done so for free. Ford went to aluminum bodies for this very reason. To save weight and fuel! Look at the max tow capacity of F150's and you will see 4 wheel drive vehicles are lower than 2 wheel equivalent. That's due to all other components being the same in both types, the weight of the front driveline is just useless weight being carried around not needed 99.9% of the time. That difference in capacity is equal to the weight of the front drive line. It's like hauling three or four hundred pounds of sand around. Forever! Four wheel drive costs you money on every mile. Period.! Two miles per gallon spread over one hundred thousand miles amounts to 555 extra gallons assuming your getting around 20 MPG. (Very generous overall) If it's diesel @ $3 bucks a gallon that comes to over $1600 bucks and in my case where I sold the last truck with 366,000 miles on it, that is $6000 dollars wasted. Not mentioning the extra maintenance involved or lousy tire wear that always comes with 4 X 4's. And I cannot remember a time when four wheel drive was really necessary. The only justification for four wheel drive is if you absolutely must get someplace once in three or four years and you live in the snow belt or perhaps a long muddy driveway. And it guarantees nothing there either. Usually you just get stuck all the deeper. Most are purchased for looks and ego. I know, I've had many of them.

Todays F150 4 X 4's are different than in years past. It was once true that a four wheel drive truck made a much better towing machine. Todays are really nothing more than a front wheel drive unit stuck into a truck frame. The heavy solid axle is gone. But so has the lousy fuel mileage. Perhaps some gains in economy come with that, but it does nothing for towing.

Siskiyou

DelawareDead

Great thread! Thanks for all the info!

Norotso

I will disagree with this statement, and driving in winter conditions for a solid 5 month a year has proven very useful in my opinion. The nice thing about the e-locker is that is self disengages after 30kph in my truck, here I use dedicated winter tires so lots of times there no need for 4x4, just turn on the e locker and disengage the anti spin and go for city driving....

jetjoe

This may have little to do with towing, however after installing modestly larger wheels and tires on my 16 screw (245/70-17 to 275/65-18) I did experience a reduction in gas mileage of approx. 1 MPG. I have the 3.5 NA (Great engine!) which consistently got 24 MPG. Now I have to really baby it to get near 23. This is also reflected in the DTE falling from between 500 and 510 miles to empty down to 480. And also the cruise RPM's dropped as expected a few hundred rpms at 75 MPH to around 1900 from 2100. One mile per gallon wouldn't deter many from going with the larger custom wheels and tires but I think this does demonstrate that even a small change does make a noticeable difference.

The engine handles this quite well. We live in the mountains of Tennessee and I can't really notice any excessive downshifting with the change. We have a mile long grade just north of Chattanooga that will drop the OD out but on only one occasion did it drop a second gear. This hill is enough to slow nearly every vehicle on the highway. The change has it's pluses and minuses. With the original wheels pulling the heavy trailer was a bit of a workout especially when passing a truck on a two lane highway. You better be paying attention as the sudden wind gusts tend to whip the trailer side to side. With the larger wheels, this has all but disappeared but at the cost of 1 MPG forever.

Knowing the tow capacity is limited by the weakest component, it is certainly something to consider when you decide just how big those new wheels should be. Which is what this post started out to be. As stated above, the lower gear ratio's that come with the high tow weight trucks are likely compensating for the larger heavier tires that Ford installs with these packages. Not to ease the load on the engine.


After spending some time with the various gear options offered for towing, it is pretty obvious that the gearing is matched to the wheel size. Doing the numbers, the RPM's pretty much remain the same. So, I would guess the wheel/tire size is where the load capacity is gained vs. the rear axle gearing.

smokeywren

Did you calculate MPG after you corrected the speedo for the fewer tire revs/mile? Without a corrected speedo, the mileage in the trip meter will be low by 4.8%, giving you inaccurate MPG. 300 miles per the uncorrected trip meter would be an actual 314.4 miles. If your fill up required 20 gallons, calculated MPG using 300 miles would be 15 MPG, but calculated MPG using 314.4 would be 15.72. That would account for most of your calculated reduction in MPG