18 F-150 diesel
01-23-2018, 07:28 AM
#71
Forks your lift
Since 2015, all the manufacturers have subscribed to establishing the GCWR by the SAE J2807 specified tests. The tests require that the trailer must have at least 10% of the trailer weight on the tongue and that the weight of the vehicle must not exceed the GVWR during the test.
The test is done with 300 lbs. of occupants and cargo in the truck and 10% of the trailer weight on the tongue. So with that 11,400 lb. trailer, it has 1140 lbs. on the tongue. A weight distribution hitch can transfer 20% of the tongue weight to the trailer axles, so 80% of the tongue weight will show up on the truck axles. So (1140 x 0.8) + 300 lbs. of occupants requires 1440 lb. truck payload to pass the test.
The rub comes when John Doe truck buyer has a trailer with 15% of the trailer weight on the tongue and loads 700 lbs. occupants and cargo in the truck. Now there is 1710 lbs. on the tongue with that same 11,400 lb. trailer. So (1710 x 0.8) + 700 lbs of occupants requires 2068 lbs. of truck payload. Most half ton trucks don't have 2068 lbs. of payload.
The mice type at the bottom of the Ford towing guide says to not exceed the GVWR of the truck. Most who look at the towing guide just overlook that part.
http://www.automotive-fleet.com/fc_r.../pdf/j2807.pdf
The test is done with 300 lbs. of occupants and cargo in the truck and 10% of the trailer weight on the tongue. So with that 11,400 lb. trailer, it has 1140 lbs. on the tongue. A weight distribution hitch can transfer 20% of the tongue weight to the trailer axles, so 80% of the tongue weight will show up on the truck axles. So (1140 x 0.8) + 300 lbs. of occupants requires 1440 lb. truck payload to pass the test.
The rub comes when John Doe truck buyer has a trailer with 15% of the trailer weight on the tongue and loads 700 lbs. occupants and cargo in the truck. Now there is 1710 lbs. on the tongue with that same 11,400 lb. trailer. So (1710 x 0.8) + 700 lbs of occupants requires 2068 lbs. of truck payload. Most half ton trucks don't have 2068 lbs. of payload.
The mice type at the bottom of the Ford towing guide says to not exceed the GVWR of the truck. Most who look at the towing guide just overlook that part.
http://www.automotive-fleet.com/fc_r.../pdf/j2807.pdf
01-23-2018, 11:21 AM
#72
Senior Member
300lbs of occupants and cargo in the truck? Heck with me, the tiny human, and the random tools i have in my truck, i am already over that 300lbs. Are they banking on a single guy with a small bag of clothes to tow these huge trailers? Most people who have big trailers typically have a family size minimum of 2 people. How many married couples do you know of are a combined 300lbs with anything else in the cab/truck?
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01-23-2018, 12:58 PM
#73
Forks your lift
shoot i am no where petite and my tiny is like her daddy. Between the two of us, her car seat, and diaper bag we already hit the 300lbs lol
01-23-2018, 01:25 PM
#75
01-23-2018, 01:26 PM
#76
With the 3.5EB, the phase "torque peak" is very misleading. It's more like a giant plateau that starts below 2,000 RPM and holds to about 5,000 RPM. The torque curve is so flat that the torque available at the crank at 2,500 RPMs and 3,500 RPMs is almost identical.
The Five Star dyno chart doesn't even start until 2750 RPM and it looks like that is where torque is the highest and it fall off as RPM increase. This is not necessarily in conflict with Fords specs (assuming 3,500 is the correct spec). You have to understand that the torque curve at the rear wheels is always a little different than at the crank. Ford is rating it at the crank. Due to the increased resistance as you spin a transmission faster, a higher proportion of crank torque made at lower RPMs makes it to the rear wheels compared to higher RPMs.
But back to my initial statement... so what if it makes 470 at 3500RPM vs. 469 at 2500 RPM or the reverse. The torque curve is as flat as it gets this side of the early 4 valve 5.9 Cummins and that big torque is available below 2000 RPM.
Also, it would not surprise me if the stock tune on the Expedition is a little hotter than on the F-150. The Expedition is rated to tow less and generally will see a lighter duty cycle. So Ford could confidently push the envelope a little more on the Expedition than an F150. And the small differences in the specs could easily be achieved by tuning differences - mechanical difference not needed.
The Five Star dyno chart doesn't even start until 2750 RPM and it looks like that is where torque is the highest and it fall off as RPM increase. This is not necessarily in conflict with Fords specs (assuming 3,500 is the correct spec). You have to understand that the torque curve at the rear wheels is always a little different than at the crank. Ford is rating it at the crank. Due to the increased resistance as you spin a transmission faster, a higher proportion of crank torque made at lower RPMs makes it to the rear wheels compared to higher RPMs.
But back to my initial statement... so what if it makes 470 at 3500RPM vs. 469 at 2500 RPM or the reverse. The torque curve is as flat as it gets this side of the early 4 valve 5.9 Cummins and that big torque is available below 2000 RPM.
Also, it would not surprise me if the stock tune on the Expedition is a little hotter than on the F-150. The Expedition is rated to tow less and generally will see a lighter duty cycle. So Ford could confidently push the envelope a little more on the Expedition than an F150. And the small differences in the specs could easily be achieved by tuning differences - mechanical difference not needed.
300lbs of occupants and cargo in the truck? Heck with me, the tiny human, and the random tools i have in my truck, i am already over that 300lbs. Are they banking on a single guy with a small bag of clothes to tow these huge trailers? Most people who have big trailers typically have a family size minimum of 2 people. How many married couples do you know of are a combined 300lbs with anything else in the cab/truck?
01-23-2018, 09:27 PM
#78
Senior Member
You're assuming most people tow campers. A guy with his work tools loaded in his trailer and just him with his weight distributing hitch hooked up is darn near exactly 300lbs. There has to be a standard even though how we use trucks isn't standard.
01-23-2018, 09:43 PM
#79
For 76l\k - 69k after dealer discounts, you can get an F350 Lariat with EVERY single option it allows. I would neevr spend 60 something on this when for 15 more i could have a 350.
01-24-2018, 03:57 PM
#80
Senior Member
300lbs of occupants and cargo in the truck? Heck with me, the tiny human, and the random tools i have in my truck, i am already over that 300lbs. Are they banking on a single guy with a small bag of clothes to tow these huge trailers? Most people who have big trailers typically have a family size minimum of 2 people. How many married couples do you know of are a combined 300lbs with anything else in the cab/truck?