Hitch setup analysis--F150 & Bigfoot 25B25RQ

[Derek Johnson]

We are getting ready to leave on a trip and since everything is loaded I decided to spend some quality time at the local weigh station. This is also a bit of a followup to a recent thread for which I wanted to provide more detailed data. All numbers (except for one column) are for a fully loaded truck and trailer with a full gas tank, full water tank, 2 full large propane tanks, 1 battery, empty waste tanks, and no passengers. The truck and trailer are loaded for a two week trip. The scale is a State of Washington highway weigh station that measures in 20 lb. increments and can measure one axle at a time.


Truck:
2005 F150 Crewcab (4 door), 5.4L V8, 3.73 rear axle, towing package
Leer canopy
Equalizer hitch with 6 washers
Cargo limit 1299 lb.
GVWR 7200 lb. (max truck weight with everything in it)
GCWR 14500 lb. (max weight of truck and trailer and everything in both)
Trailer towing capacity 8700 lb.


GAWR Truck W/O WD W/WD No Water
Front axle 3750 3280 2900 3320 3360
Rear axle 3850 3140 4360 3700 3520
Trailer axles 7000 ---- 5680 5880 5640


Truck wheelwell heights:
Loaded truck, no trailer: Front 37.25", Back 38.25"
Trailer with WD: Front 37.25", Back 37"

Trailer level:
Front of trailer is 0.75" lower than rear



Comments:
1. Passengers are not included in any measurements. In our case the 2 of us will add about 300 lb. to the total weight.

2. Without the weight distributing bars hooked up the truck is 380 lb. lighter in front and exceeds the max weight for the rear axle by 510 lb. Our previous hitch setup was not transferring enough weight off of the back axle and I had to add 2 washers to tilt the hitch head downward more. Towing this size trailer without a WD hitch looks like a bad idea.

3. The WD bars transfer over 600 lb. off of the rear axle. About 400 of it goes to the truck's front axle, and about 200 goes to the trailer axles. The number don't exactly add up, which I attribute to the 20 lb. increments of the scale. Sometimes the numbers flicker up or down to the next increment.

4. Interestingly, while the axle weights are safely below the maximums and the combined weight of 12,900 lb. is 1600 lb. below the max of 14,500 lb., the truck GVW is 7020 lb., only 180 lb. below the GVWR of 7200 lb. When my wife and I get in the additional 300 lb. will put us over the max weight by 120 lb. Also, the back of the truck still has room for cargo that would put us further over the limit if we were to make use of the space.

5. Both the truck and trailer are very level--the front of the truck is right back where it was before connecting the trailer and the back has only drooped 1.25".

6. I disconnected the trailer to measure tongue weight and with only the tongue on the scale I got a reading of about 940 lb. This number changed quickly with even the slightest change in elevation of the tongue. However, comparing the total truck weight without the trailer with the weight with the WD hitch, the truck is only experiencing an additional 600 lb. of downward force. So what is the actual tongue weight?

7. While the truck manual says you can tow up to an 8700 lb. trailer, this is probably true only if you have no cargo in the truck and no passengers. The trailer weight is somewhere around 6620 lb. (5680 lb. w/o WD + 940 lb. of tongue by itself). This looks like I have about 2000 lb. of capacity left, but I am only 1600 lb. away from my max GCWR. The other 400 lb. is probably about the weight of my cargo and canopy. So, if I emptied all cargo, removed the canopy, and didn't have passengers I could do it. But, I am only 180 lb. away from my GVWR of 7200 lb. So, almost all of the additional 2000 lb. must be handled by the trailer axles and not transferred to either of the truck axles. The 8700 lb. rating is not what you would call conservative...

8. I think that an F150 can safely tow this weight trailer and stay within its rated capacities, but it is right at the upper limit. Running without a full water tank frees up about 400 lb., which can help. If buying a new tow vehicle it would probably be best to buy an F250.

Wow--made it this far did you? Nice job

Derek

[cpaharley2008]

That is the problem with 1/2 ton trucks, they can pull a lot but can not haul a lot. With 940# tongue weight, canopy and passengers you are over limit. Your hitch/ball/receiver may also have their own limits, be sure and check those.

[Bob Miller]

Gotta say, pullng a trailer with almost 1/2 ton of tongue weight, with a truck that is rated to carry just a few lbs more is sorta pushing it.....

When Ford said "up to 8700 lbs" that is not a starting point, but an end point.

For starters I would try to shed as much weight as possible, like not carrying more than a few gallons of water or waste between stops.

[Brian B-P]

Excellent info - thanks for keeping track of everything and sharing it, Derek!

The forum software ruins the formatting of information presented in columns. It can help to force it to display more like the way you typed it, but putting it in a "code" block (although that's not the purpose of this feature):

                   GAWR      Truck      W/O WD     W/WD     No Water
Front axle       3750       3280       2900          3320       3360
Rear axle        3850        3140       4360          3700       3520
Trailer axles    7000         ----       5680          5880       5640

As others have noted, "1/2 ton" full size pickups are often not really configured for work anymore. They have so much luxury equipment in them (using up load capacity) and such soft suspension (limiting axle capacity) that there is little capacity left. This F150 has about the same payload capacity as our front-wheel-drive minivan. The 710 pound remaining rear axle capacity in an empty truck seems laughable to me.

Originally Posted by Derek Johnson

6. I disconnected the trailer to measure tongue weight and with only the tongue on the scale I got a reading of about 940 lb. This number changed quickly with even the slightest change in elevation of the tongue. However, comparing the total truck weight without the trailer with the weight with the WD hitch, the truck is only experiencing an additional 600 lb. of downward force. So what is the actual tongue weight?

Adding the trailer without a WD system to confuse things adds 1220 pounds to the truck's rear axle, of which 380 pounds has been shifted from the truck's front axle, leaving 840 pounds net change - the tongue weight. There's +/-40 pounds of uncertainty in this due to the usual scale precision limit, plus any error due to other scale errors.

To do this with the WD system, all axles need to be accounted for. The total rig (all three axles) weighs 12940 pounds (measured without WD) to 12900 pounds (measured with WD) - the weight is the same but the measured number is different due to the scale precision limitation. The trailer axle carries 5680 pounds of this, and the truck itself is 6420 pounds, leaving up to 800 pounds... with lots of uncertainty.

Three ways to get the tongue weight, all about the same within error tolerances. There could be real differences because the load carried by the tongue does vary significantly with coupler height in a tandem axle trailer, because the distribution of load between the axles is not equal and depends greatly on suspension position. It is unlikely that the coupler height was identical in WD and non-WD situations. The direct measurement is the most accurate, but the other numbers are lower, so I would say that the best guess is 930 pounds.

If 930 pounds on the ball pries 380 pounds off the the tongue, the ball must be behind the rear axle by 380/930 = 41% of the wheelbase. That's 57" (if it is the 5.5' box and 139" wheelbase) or 62" (if it is the 6.5' box and 151" wheelbase). Using a normal ball mount rather than the WD head would bring the ball closer and reduce this lever arm length, and thus the load transfer off of the front axle, but that's not an option with over 900 pounds of tongue weight.

Originally Posted by Derek Johnson

Towing this size trailer without a WD hitch looks like a bad idea.

The tongue weight seems to me to be unnecessarily high for a 6610 pound trailer... especially one being pulled by a vehicle with so little hitch weight capability and such long wheelbase for stability. I would say that towing a trailer with this much tongue weight with a light-duty vehicle and without a WD hitch looks like a bad idea. Hook the same trailer to an F350, or shift some load back from the trailer tongue, and towing without WD could be a perfectly good idea.

Originally Posted by Derek Johnson

Also, the back of the truck still has room for cargo that would put us further over the limit if we were to make use of the space.

Welcome to the situation experienced by other pickup owners... at least the ones who take the care to check.

Originally Posted by Derek Johnson

7. While the truck manual says you can tow up to an 8700 lb. trailer, this is probably true only if you have no cargo in the truck and no passengers.
...
The 8700 lb. rating is not what you would call conservative...

Not "probably": Ford is very clear in its towing information that their pickup truck limits are calculated with no cargo, no passengers, and only a specific weight of driver (which is probably lighter than the average adult male). The rating is an upper limit, just as Ford explains. Rather than picking arbitrarily lower number and letting people decide how much room to go over they should assume, a clear limit is provided. That seems reasonable to me.

[Brian B-P]

Originally Posted by Bob Miller

When Ford said "up to 8700 lbs" that is not a starting point, but an end point.

I agree. Of course, that's half a ton above the trailer's maximum weight.

Originally Posted by Bob Miller

For starters I would try to shed as much weight as possible, like not carrying more than a few gallons of water or waste between stops.

Personally, I would be very disappointed to buy a full-sized truck, pull a trailer with hundreds of pounds of extra axle capacity, and need to fuss with the water level in the tank every time I moved and being controlled by dump site locations.

The load problem is tongue weight, not total trailer weight, so I would rather get something off the tongue.
Clarification on edit: "something" does not mean water.

[Bob Miller]

RE: Tanks:: Depending on the location of the tanks they may increase, decrease or have no effect on tongue weight. And it's still 400+ more lbs to have to stop in a rig that is already very near it's upper limits.

[Brian B-P]

Originally Posted by Bob Miller

RE: Tanks:: Depending on the location of the tanks they may increase, decrease or have no effect on tongue weight

True, and this is one reason to put some effort into understanding the specific rig.

In Derek's numbers emptying the water tank takes 380 pounds off the total, and only 240 pounds of that off the trailer axle, suggesting that the water tank is well ahead of the axle. Emptying the tank also takes 180 pounds off the rear axle and adds 40 pounds to the front axle, suggesting that the hitch is carrying substantially less load. In this trailer, carrying water adds hitch weight.

Originally Posted by Bob Miller

And it's still 400+ more lbs to have to stop in a rig that is already very near it's upper limits.

I agree, but I don't think the total weight capacity is that marginal.

I would rather give up some interior room or some toys than have to worry about tank levels all the time.

[Derek Johnson]

Brian--thank you for taking the time to make such detailed comments. I appreciate the help.

We purchased this truck back when we had our Scamp and we never thought we would get a bigger trailer. It had more than enough capacity and it was an improvement over the Honda Odyssey we had used for several years. We stumbled across a great deal on the Bigfoot ten minutes from our house and couldn't pass it up. I knew that the truck towing capacity of 8700 was an absolute maximum and was considered by many to be a gross exaggeration, but since the Bigfoot had a dry weight of around 5500 lb. I figured it would be OK. Little did I know at the time that towing something 2,000 lb. under the limit would be pushing it under any kind of normal circumstances (canopy, a passenger, and some cargo). It think that is the primary lesson here--for an F150, you will max out at 2000 lb. under the rating and probably should stay 3,000 lb. under to allow you to pack the truck and trailer full and not worry. So, for my truck, the max weight for a fully loaded trailer should not exceed around 5700 lb. Maybe everyone else already knows this, but I didn't.

Clearly, an F250 or larger is the right choice to tow this trailer. If I had bought the trailer first, and know what I know now, that is what I would do. The situation now, however, is I have a nice truck that I use as a daily driver, it meets all the rest of my needs, and I am not in a position to replace it at the moment (one kid in college, another almost there…). I tow perhaps a half dozen times a year, mostly locally, and I would like to see if there is a way that I can use this truck for now to tow safely. Hence, the measurements…

A few miscellaneous comments:

1. The truck is the 139" wheelbase (the short box model). It has 18 inch wheels, which reduces the max tow capacity a few hundred pounds, and has LT tires with a capacity of 2535 each. With the tow package and 3.73 rear end it has more towing capacity than a lot of F150's ( yes, some are going to fare worse than mine in an identical situation). It also has four new tires, new NAPA ultra-premium rotors and severe-duty pads, and a new P3 brake controller. By the way, I love this controller compared to my earlier Voyager model. It is very easy to alter settings on the fly. The LCD display is easy to see and the buttons are easy to reach. My favorite thing being able to press one button and change to boost level two when in heavy traffic or on a steep hill--this starts the trailer braking sooner. A few button presses later and it is back to the previous setting.

2. I forgot to mention there are two adult size bike mounted on the bumper of the trailer which will affect the tongue weight.

3. The 710 lb. of remaining capacity on the rear axle is with the truck already loaded--the measurements for the truck only are for the loaded truck. I have a small inverter generator, 2 gal. gas, our 2 Cabela's recliners and a few other chairs, and three boxes of gear in the back (I'm not sure of the total weight and should have measured the truck before loading). I don't know the cargo capacity of our Honda van, but I know it didn't handle the Scamp nearly as well as the truck. This issue of cargo capacity may be different than towing ability, however.

4, I don't know why the tongue weight is so high. Last time I measured it I swear it was in the 600 lb. range, but I didn't record all of the details then. This time I made sure both large propane tanks were topped off and the water was full to the top. Bigfoot claims, on the sticker inside the wardrobe, that it carries 51 gal. of water weighing 425 lb., but the brochure lists 45 gallons. The water tank is forward of the axles and the tongue weight should lessen as water shifts to the waste tanks which are farther back. Also, the battery is the largest size 12 volt (group 31?) and sits forward of the two propane tanks. If the trailer weighs about 6600 lb. loaded, the recommended 10-15% tongue weight is 660-990 lb., so maybe 800-900lb. isn't that bad (just a lot…).

5. Before hooking up the trailer the truck axles were supporting 6420 lb. With the trailer and the WD hooked up the truck axles were supporting 7020 lb., an increase of 600 lb. The trailer axles were supporting 5880 lb., not 5680 lb.

6. It was mentioned that I am over limit. Even with the two passengers it will be under on both axle ratings (GAWR), 1300 lb. under the total weight of both vehicles (GCWR), at least 1000 lb. under on the trailer axles, and over 1000 lb. under the truck tire ratings per axle. The only rating it will be over on is the GVWR, and only by 100 lbs. And, this will improve as fuel, propane, and water are used. So, yes, it is over, but I'm not sure by enough for me to refuse to tow. I think the important thing is for me to realize how close to the load capacity I am and to be careful. A definite drawback is I can't pack full every available space on the truck and trailer and I have no extra capacity. One might argue, of course, that if Ford's load ratings for each axle are as bad as its rating for towing capacity, then I might be screwed by even coming near them.

7. I just towed the Bigfoot across WA and OR this weekend and am writing this from Lake Tahoe. With the adjustments I made (adding two washers to increase the WD) it definitely seemed to tow better. I think I had more bounce on the back axle before, which is not surprising as it was overloaded. I do have more noise from the Equalizer hitch when turning slowly in the campground and it was marring the inside corner of the pins that keep the bars on the L-bracket. We hit some very high winds, so bad that all bus and RV traffic was banned on northbound 580 near Reno (we were entering southbound), and I had no sway whatsoever. It feels like it is towing well, but my only other experience is with the previous hitch setup and of course with our Odyssey and the Scamp, so what do I know…


Thanks again for the comments. I am trying to learn and be safe and I am not always sure I am looking at the data correctly, so your thoughts are helpful.

Derek

[Brian B-P]

Originally Posted by Derek Johnson

3. The 710 lb. of remaining capacity on the rear axle is with the truck already loaded--the measurements for the truck only are for the loaded truck. I have a small inverter generator, 2 gal. gas, our 2 Cabela's recliners and a few other chairs, and three boxes of gear in the back (I'm not sure of the total weight and should have measured the truck before loading).

Ah, good catch. I was thinking of that as curb weight, not loaded weight, in my comment; that's a significant difference. It still doesn't seem like a lot for a full-size truck, with that stuff in it...

[Brian B-P]

Originally Posted by Derek Johnson

4, I don't know why the tongue weight is so high.
...
Bigfoot claims, on the sticker inside the wardrobe, that it carries 51 gal. of water weighing 425 lb., but the brochure lists 45 gallons.

I assume that's the same volume expressed in two different units of measure: 51 U.S. gallons, or 45 Imperial gallons.

Originally Posted by Derek Johnson

If the trailer weighs about 6600 lb. loaded, the recommended 10-15% tongue weight is 660-990 lb., so maybe 800-900lb. isn't that bad (just a lot…).

I agree, it isn't unreasonable, but since the truck's ability to carry hitch weight is the biggest limitation, maybe it would be desirable to shoot for the low end of that range rather than the high end.

[Derek Johnson]

There aren't many options for easily altering the tongue weight on this trailer. The rear of the trailer is the bed, and there is only one storage area underneath that we could pack a few heavier items in. Other than that, I think carrying less water is the main option, and it only takes 140 lb. off the truck if completely empty. That is inconvenient and I doubt I would ever travel with less that 1/4 to 1/2 tank.

Derek

[honda03842]

This is based upon a small tow vehicle and a small trailer compared to your set up but may help.

We are limited to 220 lbs of tongue weight. As a result we have done as much as possible to stay within the tongue weight limits. Typically our tongue weight is 200 lbs or less.

We began by limiting ourselves to one 20 lb propane tank instead of the more typical two tanks. The two big tanks you have are heavy and so is the propane. One 20lb tank easily last us a month. Even with our heavy travel schedule this has not been a problem. As a 'never used' backup we carry a one lb propane tank.

Our battery is heavier than our propane tank and is located behind the propane tank, a small thing but in the right direction.

As to the water tank, our's is behind the axle so it subtracts from the tongue weight (Why all water tanks are not over the axle is a mystery). Regardless, we travel with about 4 gallons of water. That really is plenty for the road. We simply fill up before reaching a waterless campsite, towing water a few miles at most instead of hundreds. We try to dump both tanks as soon as possible when leaving a campsite as most people do.

The only really heavy item we carry is our Volcano Grill. We carry that between the Honda's axles in front of the rear seats. As to chairs, we've chosen four all aluminum chairs, light and never rust.

We try to locate the heavy items we carry in the trailer like liquid drinks and canned goods right over the axle; lighter items like clothing and bedding are typically at the ends of the trailer.

Every summer when we return we consider our set up and try to eliminate things we never use and don't need. Not that this exercise saves a lot of weight but it provides a measure of reorg and provides re-enforcement of 'less is best'.

Hope this helps.

[Derek Johnson]

I think you are right about the propane as one place to save weight. We have 2, 30 lb. tanks and they are definitely heavy. And maybe I'll just have to give in and carry less water until we reach our destination. Those seem like the two biggest places to make a difference.

Derek

[Brian B-P]

30 pound capacity propane tanks typically weight about 25 pounds each, so the easiest approach of leaving one behind saves 25 to 55 pounds, almost all of which is tongue weight, depending on how full your tanks typically are. Unfortunately, running with a single tank means no reserve if it happens to run out at an inopportune time, and 20 pound tanks - the empty tanks themselves - are each only about 7 pounds lighter.

[Brian B-P]

I agree that once the manufacturer has established the locations of all of the components, substantial change in mass distribution is tough... and piling cargo at the rear end is not good for stability. I'm not sure which photos on Bigfoot RV's page correspond to which model (I think only image 14 is the 25B25RQ, and 24 to 28 are the 25B25FB ), but it looks like all of the big appliances (including furnace and water heater) of the 25 footer are already near the middle of the trailer; that's good, but doesn't leave much room for improvement.

The only thing that seems obvious as a candidate mass to move from the very front to nearer the axle is the battery. On a small egg there's not much choice in location that doesn't cause other stuff to be moved, but on a 25B25RQ is there room below the floor, outboard of the frame, ahead of the wheels on either side for a battery box?

The battery may only be 60 pounds, but if it could go from 90% hitch weight to 10% hitch weight that would be about 50 pounds of the hitch with zero loss of functionality... and without harm to stability. From photos on the manufacturer's website, it looks like a 25B25 has the bottom of the floor at about the top of the tires, which would be about 28" off the ground. That seems like enough height to put a battery under it and leave sufficient ground clearance, as long as the battery is close to the axles.

Propane is the other built-in thing on the tongue, and an underfloor permanently mounted tank (like a typical motorhome) could be closer to the middle, but that's essentially never done on a trailer (for a couple of reasons that I can think of).

Another way to reduce tongue weight is to extend the tongue, leaving everything where it was, except the coupler which moves forward. The increased distance from ball to trailer mass improves stability. Unfortunately, a meaningful change would require too much extension to be practical. If a trailer is 15 feet from axle to coupler with 15% tongue weight, then it would take over 7 feet of extension to get it down to 10% , and 2 feet of extension would only get it down to 13% (if I did my math right). It's not a huge potential, it would be far from trivial to do, and it has other consequences (e.g. to maneouverability).

[Night Sailor]

Excellent analysis. I agree completely about the 3/4 ton upgrade. I' e owned half ton trucks and even with upgraded springs and shocks I found myself wishing I has a 3/4 ton. I now drive a one ton and for some years found myself wishing I had a 3/4 ton, but as time goes on, I find the durability of the 4x4 1-ton suits me even though their is fuel economy hit for turning the dual wheels and heavier drive train. When in doubt, going up a size is always wise. I never want to get stuck or break down.

[Derek Johnson]

My previous truck, which I drove for 25 years (and my son is driving now), is an F100. I thought that this F150 with the towing package, 4 wheel drive, and 3.73 limited slip rear end was a fairly significant upgrade compared to what I was used to...

Derek

[honda03842]

Brian,
I suspect a larger truck is coming for the Bigfoot. However reducing the propane load is easy to do. We've traveled for 6 years with only one 20 lb tank and never run out.

We start every year's travels with a full propane tank and probably fill it every 1-2 months. With propane readily available one tank is no more a problem than gasoline.

For the last couple of years we've carried a 1 lb tank as a back up, enough to carry us for a day or two.

In our case to improve the effective of tongue weight I recently shortened the ball distance to the axle by about 5%. A valuable savings with a tow vehicle with limited tongue weight capacity. A small change but in the correct direction.

[Derek Johnson]

Have you priced trucks lately? The equivalent of my truck in an F250/F350 would be in the $50,000-$60,000 range. That's new, of course, but still...

Have you priced college lately? If you aren't poor, rich, or manage to land a great scholarship you are going to pay for it all yourself. Gone are the days that kids could work over the summer and save enough for tuition. My monthly room/board/tuition cost is more than what some pay for their mortgage. And, my second kid will be there after next year.

No, there is no new truck for at least 6 years. If there is a way to make this one work safely for now, that is what is going to happen even if there are compromises involved.

Derek

[Night Sailor]

Originally Posted by Derek Johnson

Have you priced trucks lately? The equivalent of my truck in an F250/F350 would be in the $50,000-$60,000 range. That's new, of course, but still...

Have you priced college lately?

No, there is no new truck for at least 6 years. If there is a way to make this one work safely for now, that is what is going to happen even if there are compromises involved.

Derek

You can make your truck work. You have it. Why buy another truck? Make it work. It is simpler and easier, and you have already demonstrated good sense by analyzing the weigh distribution. Few people have the sense to do that. Seriously, you deserve kudo's for that!

I'd be particularly careful though, use great tires, and drive slower than a heavier duty TV if you are on the borderline of it's capacity.

I recommend tire pressure sensors for both TV and Tow. I've been in touch with a company, Orange, that is designing a sensor set for vehicles with more than 4 wheels.

I'd suggest one 6 lb aluminum propane tank. Fluid weight adds up fast. I've used these small tanks while boating and they don't run out unless someone leaves one on. Shut off at the tank. They are easy to carry when refilling. There are 10 lb aluminum versions also.


Amazon.com: Worthington 299494 6-Pound Aluminum Propane Cylinder With Type 1 With Overflow Prevention Device Valve: Patio, Lawn & Garden


There are also fiberglass propane tanks available now that weigh less and some show how much propane remains. They are certified for 10 years now. The reviews show some issues though.

Ragasco Clear View 20lb Composite Propane Tank - Propane Tanks for your Gas Grills, Patio Heaters and more - Amazon.com

This one has a steel liner.

Amazon.com : CoMet Lightweight 11lb Propane Cylinder Gray Wave with Level Gauge : Grill Parts : Patio, Lawn & Garden


Someone else mentioned you can reduce the size of your battery. Why not do that and add a small solar panel to help keep it topped up?

You are close enough to meeting your limit that you can make it work and still carry some water. As Norm said, Look at everything you don't need with an eye to tossing it out or replacing it with something lighter.