Towing calculations question

[lcrain]

I regularly (12 times a year on average) tow a race trailer with a miata or my M3 to various race tracks. I plan to order a '21 F150, 4x4, EB, 5.5' box, lariat, 502a, max trailer tow package. Here are my calculations, which lead me to believe the f150 is the right truck for my needs, vs. an f250 or the like. Please let me know where my calculations are flawed.

Trailer weight: 8000 lbs. Includes M3 (2900 lbs), tools (500 lbs), spares needed (1000 lbs) all in an all aliminum 24' featherlite trailer (3500 lb trailer).

Gross vehicle weight (7050 lb max based on specs I can find): This is where I need some input. The big assumption is curb weight of the truck itself. Based on the ford website, base curb weight of just under 5000 #s which I will round to 5300 #s for the trim level (need input here). 800 lb tongue (assumes 10% of trailer though I regularly see closer to 500 based on how I load the trailer using a hitch with an integrated scale). Three adult males: 600 lbs (sometimes I have teammates for longer hauls). Driver gear 200 lbs. Max of 6850 lbs.

Gross combined weight of 14,150 lbs. Well within the GCWR of 19,400 lbs.

The only concerning number here is the GVWR. I get awfully close to that. I appreciate any feedback.

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[rucus0101]

I regularly (12 times a year on average) tow a race trailer with a miata or my M3 to various race tracks. I plan to order a '21 F150, 4x4, EB, 5.5' box, lariat, 502a, max trailer tow package. Here are my calculations, which lead me to believe the f150 is the right truck for my needs, vs. an f250 or the like. Please let me know where my calculations are flawed.

Trailer weight: 8000 lbs. Includes M3 (2900 lbs), tools (500 lbs), spares needed (1000 lbs) all in an all aliminum 24' featherlite trailer (3500 lb trailer).

Gross vehicle weight (7050 lb max based on specs I can find): This is where I need some input. The big assumption is curb weight of the truck itself. Based on the ford website, base curb weight of just under 5000 #s which I will round to 5300 #s for the trim level (need input here). 800 lb tongue (assumes 10% of trailer though I regularly see closer to 500 based on how I load the trailer using a hitch with an integrated scale). Three adult males: 600 lbs (sometimes I have teammates for longer hauls). Driver gear 200 lbs. Max of 6850 lbs.

Gross combined weight of 14,150 lbs. Well within the GCWR of 19,400 lbs.

The only concerning number here is the GVWR. I get awfully close to that. I appreciate any feedback.

The lariat can have the widest range of payload of any of the trims. Most will weigh in closer to 5600 pounds curb than 5300. You could end up with as little as 1400 or as much as 1750 payload (always check the door sticker). Heavy options like the sunroof, power deployable tailgate, FX4, bedliner, and bed cover eat into the payload.


You also need a WDH according to ford to tow a trailer over 5000 pounds.

I would run your calculations like this


800 pound tongue weight
100 pounds WDH
600 Pounds of people
200 pounds of cargo
50 pounds (bedliner?)
75 pounds (bed cover?)


Puts you easily needing a 1850 payload truck to do what you want.

 

[lcrain]

The lariat can have the widest range of payload of any of the trims. Most will weigh in closer to 5600 pounds curb than 5300. You could end up with as little as 1400 or as much as 1750 payload (always check the door sticker). Heavy options like the sunroof, power deployable tailgate, FX4, bedliner, and bed cover eat into the payload.


You also need a WDH according to ford to tow a trailer over 5000 pounds.

I would run your calculations like this


800 pound tongue weight
100 pounds WDH
600 Pounds of people
200 pounds of cargo
50 pounds (bedliner?)
75 pounds (bed cover?)


Puts you easily needing a 1850 payload truck to do what you want.

Thank you for the feedback. Stuff like this is super helpful but really makes me wonder how ford gets to a 14k towing capacity. WTF are they towing to be able to fit within these specs? Neither here nor there.

Just a bit more about my plans for the truck. I do want the big sunroof, but willing to forgo that (~100 lbs from my research). I do also want a bed liner and a bed cover. No plans to order the power tailgate or FX4.

For reference I have been towing a slightly lighter and smaller 20' featherlite for a few years behind my '13 f150 platinum without a WDH. Sounds like Ford recommends against that practice. I do use airbags in the rear to keep the ride level, not sure if that is accomplishing the same objective fully, but maybe it helps a bit. I have never had any issues, knock on wood, but I will likely be ordering one regardless of which truck I buy.

I was really hoping I wouldn't need to step up to an f250, but seems like that will afford me more wiggle room. The prices are one thing, but the sheer size of those trucks is nothing short of imposing for 90% of my usage (daily driving). I doubt I can even fit it in my parking garage at work.

 

[rucus0101]

Thank you for the feedback. Stuff like this is super helpful but really makes me wonder how ford gets to a 14k towing capacity. WTF are they towing to be able to fit within these specs? Neither here nor there.

Just a bit more about my plans for the truck. I do want the big sunroof, but willing to forgo that (~100 lbs from my research). I do also want a bed liner and a bed cover. No plans to order the power tailgate or FX4.

For reference I have been towing a slightly lighter and smaller 20' featherlite for a few years behind my '13 f150 platinum without a WDH. Sounds like Ford recommends against that practice. I do use airbags in the rear to keep the ride level, not sure if that is accomplishing the same objective fully, but maybe it helps a bit. I have never had any issues, knock on wood, but I will likely be ordering one regardless of which truck I buy.

I was really hoping I wouldn't need to step up to an f250, but seems like that will afford me more wiggle room. The prices are one thing, but the sheer size of those trucks is nothing short of imposing for 90% of my usage (daily driving). I doubt I can even fit it in my parking garage at work.

The truck that pulls 14K pounds is a XL with the HDPP package, something you will never ever see in the wild, its like a unicorn. The test is done with a skinny ass 150 pound driver and a 150 pound passenger and no cargo and perfectly loaded / balanced trailer.

The sunroof in previous generation was 68 pounds (they havent released the option weights on the current generation to the public). The WDH requirement is because J2807 has specific requirements around understeer when pulling a trailer (you see the f250 has this big ass counter weight in the front that prevents that, thats why with the f250D you can go to 21k with no WDH). The WDH puts weight on the front axle to correct for the understeer. Ford/J2807 has deemed that anything over 5000 pounds poses a risk to not meet the understeer requirement. Airbags dont help alleviate that requirement they actually make it worse in some cases as raising the rear will take more weight off the front.

If you can live with just a 502a, dump all the heavy options, get the 18" wheels, maybe even go for the 6.5 bed as it picks up around 50 pounds extra payload you can get a truck with almost 1800 pounds payload as a lariat that is decent equipped. Maybe put some of that 200 pounds of stuff in the cargo trailer. Go with a removable bed rug, and a cover you can remove when you are towing I think you will be close to what you need.

 

[chrisp993]

Same situation, I tow an 8,000lb race trailer with my 2016 F150 Lariat, and have a 2021 Platinum on order. The problem is payload (as noted above) and in your case 600lbs of teammates ...

I'd also suggest you research tongue weight vs sway ... 500lbs is way low for an 8,000lb trailer? Possible you are trying to stay within payload? But I'd rather be a couple of hundred pounds over payload than have the trailer wag around on me ...

 

[lcrain]

Same situation, I tow an 8,000lb race trailer with my 2016 F150 Lariat, and have a 2021 Platinum on order. The problem is payload (as noted above) and in your case 600lbs of teammates ...

I'd also suggest you research tongue weight vs sway ... 500lbs is way low for an 8,000lb trailer? Possible you are trying to stay within payload? But I'd rather be a couple of hundred pounds over payload than have the trailer wag around on me ...

Thank you for the feedback. I should also say that I only have the passengers for potentially two weekends a year when we take the miata to destination tracks. So with the miata instead of the m3 (2200 vs 2900 lbs), might be a lot closer. Need to do some more exact calculations on spares also. I used a number with some fluff in there. 1000 lbs of spares is almost half the damn car which doesn’t seem realistic. Maybe closer to half that in reality.

When I tow my m3 it is always just me. So take out 400 lbs of passengers and probably 150 lbs of gear.

You are right about my light tongue weight in an effort to minimize payload. Need to do some research on that. Thanks again.

 

[kavm]

I regularly (12 times a year on average) tow a race trailer with a miata or my M3 to various race tracks. I plan to order a '21 F150, 4x4, EB, 5.5' box, lariat, 502a, max trailer tow package. Here are my calculations, which lead me to believe the f150 is the right truck for my needs, vs. an f250 or the like. Please let me know where my calculations are flawed.

Trailer weight: 8000 lbs. Includes M3 (2900 lbs), tools (500 lbs), spares needed (1000 lbs) all in an all aliminum 24' featherlite trailer (3500 lb trailer).

Gross vehicle weight (7050 lb max based on specs I can find): This is where I need some input. The big assumption is curb weight of the truck itself. Based on the ford website, base curb weight of just under 5000 #s which I will round to 5300 #s for the trim level (need input here). 800 lb tongue (assumes 10% of trailer though I regularly see closer to 500 based on how I load the trailer using a hitch with an integrated scale). Three adult males: 600 lbs (sometimes I have teammates for longer hauls). Driver gear 200 lbs. Max of 6850 lbs.

Gross combined weight of 14,150 lbs. Well within the GCWR of 19,400 lbs.

The only concerning number here is the GVWR. I get awfully close to that. I appreciate any feedback.

I think you have provided too little information. You should have enough capacity to tow 8000 lbs trailer - and are most likely limited by the payload. You need to get a better read on that. How much of the trailer load winds up as tongue weight depends upon what kind of trailer (5th wheel, bumper pull), how the dry weight is distributed and how much weight is born by the axles of the trailer vs the truck.

If the tongue weight is indeed 800lbs, you are likely not going to make it with the truck you specified. Between trailer and passenger weight - you are already at 1400 lbs [assuming your passenger weight includes the driver.] And, there is the weight of the WDH / 5th wheel hitch on top. The payload numbers seen so far would make it a very tight fit.

Just for comparison - we have a tongue weight of 800# (the mfr rating is 630#), driver + passenger weight (280#), 5th wheel hitch (rails + Anderson ultimate) 110 lbs - and a total min need of 1200# and are sweating the payload.

If your numbers are correct - you might need to rethink this a bit - either go for a low trim, options and HDPP or upgrade to the next higher truck.

 

[chrisp993]

You are right about my light tongue weight in an effort to minimize payload. Need to do some research on that. Thanks again.

It's also worth understanding how a well set-up WDH displaces load onto both the front axle of the truck *and* the trailer axles i.e. reduces the load on the rear axle of the truck. With that in mind, making sure your WDH is set up to be distributing a little more weight will help if you are otherwise at or perhaps just over the "dead weight" payload. Key measurement here will be to ensure your front fender-ground gap is slightly less with the trailer than without and certainly no more. Don't overdo this but make sure you take full advantage of what the WDH can do

 

[kavm]

The weight of WDH does not count against the payload. It has an effect but is far from a straight addition.

https://www.etrailer.com/question-180152.html

 

[daemonic3]

The weight of WDH does not count against the payload. It has an effect but is far from a straight addition.

https://www.etrailer.com/question-180152.html

Yep, from what I remember reading, it puts about 1/3 of the weight over each "axle" (the trailer counts as one axle only). So you only count 2/3 of the hitch against payload.

 

[rucus0101]

Yep, from what I remember reading, it puts about 1/3 of the weight over each "axle" (the trailer counts as one axle only). So you only count 2/3 of the hitch against payload.

Its a bit more complicated than that. When you do a force body diagram the location of the weight determines on which axle the weight is carried and its effect on the torque. Generally the "heavy" part of the WDH is the part that slides into the trucks receiver and is far away from the trailer axle, closer to the truck rear axle. Think about why your propane tanks and battery effect tongue weight so much (close to truck far away from trailer axle). So yes some weight from the WDH will be carried by the trailer axle but it will be a small amount.

One thing that is interested is in J2807 the weight of the WDH does not effect max hitch weight. In other words if you hitch is rated for a 500 pounds hitch weight and you have a 50 pounds trailer hitch that doesn't mean that you can only have a 450 pounds tongue. In other words the weight of the hitch doesn't factor into the max rating on the receiver (at least that is my interpretation of it). The hitch weight does have to be included in all payload calculations though as you cant exceed GVWR and yes with the WDH hooked up your 100 pound hitch might have 5-10 pounds being carried by the trailer axle but it shouldn't be enough to make a huge difference.

 

[daemonic3]

Its a bit more complicated than that. When you do a force body diagram the location of the weight determines on which axle the weight is carried and its effect on the torque. Generally the "heavy" part of the WDH is the part that slides into the trucks receiver and is far away from the trailer axle, closer to the truck rear axle. Think about why your propane tanks and battery effect tongue weight so much (close to truck far away from trailer axle). So yes some weight from the WDH will be carried by the trailer axle but it will be a small amount.

One thing that is interested is in J2807 the weight of the WDH does not effect max hitch weight. In other words if you hitch is rated for a 500 pounds hitch weight and you have a 50 pounds trailer hitch that doesn't mean that you can only have a 450 pounds tongue. In other words the weight of the hitch doesn't factor into the max rating on the receiver (at least that is my interpretation of it). The hitch weight does have to be included in all payload calculations though as you cant exceed GVWR and yes with the WDH hooked up your 100 pound hitch might have 5-10 pounds being carried by the trailer axle but it shouldn't be enough to make a huge difference.

I did ace statics in college and I know the spring bars create a moment at the hitch but no way am I gonna do any kind of math to get the real value. I had just googled it in the past and it stuck in my head as a rule of thumb. It will definitely vary but I figure this can't be that far off

The part about the hitch weight is very good to know too!

 

[Fordfan]

If this helps, I rolled the dice on pulling a 33" 5th wheel[10k lbs w/ gear] w/ my loaded 4x4 2016
Platinum EB max tow and it did quite well. lacked some engine braking so I had to be careful.
I added helper spring in rear, was quite stable more than anticipated. I decided to upgrade to
SD 250 because I plan to tow more often, EB did not feel under powered at any time even on the mountain roads in NV and Ut.

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