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Old 07-02-2015, 08:35 PM   #1
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Newbie Towing Numbers - Expert Fact Check, Please!

Howdy All,

I've spent a considerable amount of time learning from many of the excellent forum threads here, various tow guides, my owner's manual, etc. and think (maybe more like hope!) I have it figured out when it comes to calculating how much my TV can pull in terms of payload, trailer, etc. But, there's nothing like a little reassurance from folks that have much more experience in this area than me...a guy who's never towed anything in his life!?!

We're still looking for an AS and are trying to figure out if my current TV can handle a 22FB Sport, a FC 23D, or a FC 23FB. I've read here and elsewhere that with the F-150 it's easier to max out the GVWR before anything else, and after running some numbers I can see why. But, since we're still looking for an AS, I need some expert advice to make sure I'm on the right track.

So, here's what I've come up with. Please tell me what I've missed or overlooked.

First, the TV:

2009 Ford F-150 XLT SuperCrew w. Tow Package
145" WB, 3.55 Rear Axle Ratio
5.4L V8
Curb Weight, loaded: 5,790# (w. full fuel tank, car seat, a few tools, no passengers)
Sticker on door: The combined weight of cargo and occupants should never exceed 1,440#

According to Ford Towing Guide & Owners Manual:
GVWR: 7,200#
GCW: 15,500#
Maximum Conventional Hitch Trailer Tow Capacity: 9,700#

Passengers, fully clothed: 345#
Avg. WD Hitch: 100 lbs.

Now, the proposed AS,
FC 23D w. Hitch Weight (includes LP, no water/cargo) 720# per website

If I take 7200# (GVWR) - 5790# (curb weight) = 1410# available payload

From there, I add a safety factor of 20%, (282#) and subtract it off the bat, leaving: 1128# of available payload.

Next, I take my available payload of 1128# - 345# of fully clothed passengers = 783#

Then, I subtract the AS Hitch Weight of 720# (Yes, I know I need to weight it. But I don't have one yet so must go by AS specs.).

783# - 720# = 63# left. Now, if I attribute all of the hitch (100#) to payload, it would appear that I'm over by 37# and that's even before I add bikes (77#) firewood (70#), 1/2 tank fresh water (162#, say 60% will be attributed to additional hitch weight, a total SWAG{but will weight to be sure}, then I am over even more and would need a 3/4 ton to tow with. No?

So, if I've done this right, it would appear that I couldn't tow the FC 23D, but could tow either the 22FB Sport (393# hitch weight) or the FC 23FB (467# hitch weight), even if I added in some of the aforementioned basics to the truck payload, but maybe not a 1/2 water, I'd still be below GVWR.

In any case, I can't see a scenario where I would exceed max. tow weight of 9700# or GCVWR of 15500# since the largest AS we're considering has at GVWR of 6000# before I hit GVWR of the TV.

What have I missed, not considered for planning our first AS purchase, etc.???

Many Thanks in Advance!
John
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Old 07-02-2015, 09:49 PM   #2
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Howdy, John,
Seems to me you are good at math and deductive reasoning....

Your choice of the smaller AS would be, in my thinking, a better choice than running 'overloaded'. You 'can' probably tow the larger AS..without climbing/descending serious grades, with care.

I have towed 'outside the envelope'....many times... but, I won't do it again, if I have a choice.

It is not just the wear and tear... but, the margin of safety being compromised.

Sure, car makers will rate things to survive 'warranty'... but, may consider your safety, too... I know.. funny idea!

So, to verify your assumption, go to a UHaul or 'RV rental place and hitch up to equal weight and length SOB... this may provide your best answer before you buy an AS..

Like I said, you may be able to figure out what's best...

Peace!
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Old 07-02-2015, 10:21 PM   #3
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I'm not sure I'd put a safety factor on payload, but you have hit on the problem that most 1/2T setups have, at least from the specifications perspective - adequate towing capacity and insufficient payload. Payload and GVWR tell you what the manufacturer says the truck can carry. If you exceed the payload it puts stress on the suspension and brakes, but in my opinion the drivetrain adequacy is driven more by the towing capacity.

I don't know much about the layout of your suggested trailers, but 60% distribution of the weight of water to the tongue seems really high. I'd go with about 12% of trailer GVWR for tongue weight, or, for the 6000# trailer, 720#, all in. So I'd calculate payload as 720 + 345 +70 +77+ 100 = 1310#. At that you have about 7% margin. If your trailer weighs 6000# and 720 of that is on the tongue as payload it doesn't count as being towed. So you are towing 5280#. Take max tow and subtract the payload, 9700 - 1310 = 8390#. Here you have 37% margin.

I had a problem getting up an 8% grade with my 2006 F-150 SCrew 5.4 with 3.73 gears when I had maxed out the payload but had nearly 2000# of margin on towing capacity. I think I should have been able to climb that grade, and the problem was probably a combination of it being my first challenging tow (poor choice of gears and AC on), some blockage of air flow for the radiator and transmission cooler by bikes on a carrier in a front hitch and an old transmission filter that I thought had been changed but wasn't. Coming down that same grade, I had no problems. Downshift the transmission and use the brakes sparingly. In 3000# miles of towing with that setup I never felt like I had inadequate control or braking.

But best case, pulling the 6300# 25 footer was probably still going to be marginal. You should be a little better off with a lighter trailer but to counter that you have a worse gear ratio. Many on here tow 23 and larger with 1/2T trucks, but I recently went for the 3/4T diesel for my 25. Two tows in and I'm hooked. I don't worry about getting up the hill just around the next curve.

Al
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Old 07-03-2015, 08:58 AM   #4
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Thanks, Al and Channing. I genuinely appreciate your responses, suggestions, and advice. The information about how much 'water weight' should be assigned to tongue weight vs. trailer weight is great. I took a guess at 60%, which would include a pretty high factor of safety, but your comment about 12% seems much more reasonable.

One follow up:

Quote:
Originally Posted by Al and Missy View Post
I'm not sure I'd put a safety factor on payload, but you have hit on the problem that most 1/2T setups have, at least from the specifications perspective - adequate towing capacity and insufficient payload. Payload and GVWR tell you what the manufacturer says the truck can carry. If you exceed the payload it puts stress on the suspension and brakes, but in my opinion the drivetrain adequacy is driven more by the towing capacity.
Al
I've read about having a safety margin for towing, but would you only take a 20% safety factor for the GCVW and not for payload?

Thanks again!
John
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Old 07-03-2015, 12:16 PM   #5
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Airstream's published tongue weights are notoriously low. I think a more accurate "guesstimate" of the trailer's tongue weight (contribution to your true payload) would be to use 15% of the trailer's GVWR. 10% and even 12% are IMHO way too low.

Also note that if you want to get a fancy vanity hitch the weight will almost double from your current estimate to nearly 200 lbs.

Bottom line: You should be proud of yourself for doing all of this work so that you and your family can be as safe as possible. Unfortunately you've found that your current TV isn't up to the task. The good news: Now you get to find a new-to-you TV that will leave you plenty of spare payload to use as you please.

Here's a good tool that you might like that I found while browsing the forums:

https://www.google.com/url?sa=t&rct=...96952980,d.aWw
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Old 07-03-2015, 12:37 PM   #6
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It is not a bad thing to think it out but don't overthink it. I believe hitch weight rating is before the equalizers distribute some of it to the front wheels. I pull an '89 25 with 236 HP 240 torque and a 353 rear end (close to your TV numbers) Not ideal if you live on the mountains but it does ok on 6 and 7% grades...as good as some of the heavier vehicles and from what I am reading only the biggest diesels can pull up hill in OD, So it depends on your expectations. If you want performance you need to pay for it. I'm guessing you want to keep your current TV. I believe it will do just fine and if you are disappointed then move up to something stronger.
My 2 cents based on my 11 years with my truck and AS
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Old 07-03-2015, 12:48 PM   #7
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To the point on AS hitch weight. Our 30' is 880#, by AS. By actual scale with two full bottles it's 11,180# and we have two recliners up front so very little "extra" weight inside the trailer. I agree add 15% as suggested to the AS published weight.

That said, my rule of thumb - for me, is 25' AS and below, 1/2 ton with trailer tow option. About Diesel F250 or above. Again, don't want to start the endless battle of 1/2 vs 3/4, gas vs diesel - it's my rule for us. We had an F150 Ecoboost and towed a 25' very nicely, it towed the 30' too, but we opted to trade and move up. Again, me. Not suggesting or telling anyone else what to do.

Your numbers look good to me.
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Old 07-03-2015, 02:12 PM   #8
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Hi snarlz,

Maybe I missed it in your calculations but a WD hitch transfers some of the hitch weight back to the trailer axles. The users manual that came with my 2007 25' Classic suggests that 1/3 of the hitch weight is carried by the trailer, 1/3 by the front TV axle and 1/3 by the rear TV axle. Even if the ratios are not exactly right, that's at leas a couple hundred pounds off the TV carrying capacity.

btw, the users manual describes how to measure your hitch weight with a bathroom scale and a lever.
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Old 07-03-2015, 05:01 PM   #9
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There is at least one person who "wore out" a factory receiver on their TV. It was causing all sorts of issues.... So, yes, the hitch must handle ALL forces put on it, including rotational by the WD's.
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Old 07-06-2015, 06:20 PM   #10
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Thanks, everyone, for the incredibly helpful information! Based on your excellent inputs, it looks like I'll need to take a serious look at maybe the Sport line of AS, like the 22FB, based on what my current TV can handle in terms of payload OR maybe consider making the leap to a 3/4 ton rig if I want to tow anything much larger. Hey, who doesn't love a new truck!?! Oh...honey...guess what we're doing this weekend???
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Old 07-06-2015, 06:49 PM   #11
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I tow a 2015 25' flying cloud with a 2009 dodge ram 1500 with the 5.7 hemi. I think that is the limit for that truck IMO. The Tow/haul mode in my truck is amazing at picking the right gear going uphill, but more importantly, downhill. Doing it over again though, I would have bought a smaller trailer. As you said the 23d or 22fb might be a good choice.

If it's something you can do, get a bigger truck.
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Old 07-06-2015, 06:51 PM   #12
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I wasn't clear about 12%

Quote:
Originally Posted by snarlz View Post
Thanks, Al and Channing. I genuinely appreciate your responses, suggestions, and advice. The information about how much 'water weight' should be assigned to tongue weight vs. trailer weight is great. I took a guess at 60%, which would include a pretty high factor of safety, but your comment about 12% seems much more reasonable.

One follow up:



I've read about having a safety margin for towing, but would you only take a 20% safety factor for the GCVW and not for payload?

Thanks again!
John
I'm sorry I wasn't clearer about the 12% number. I was suggesting to take 12% of the TT GVWR and use that as an estimate of the tongue weight until you can get weighed for confirmation. As an example, AS says the tongue weight of my 2001 Safari 25 which weighs 6300# is 680#. When I weighed it, the actual tongue weight with full water tank was 860# without weight distribution set. When I set the weight distribution, the effective tongue weight, i.e. the increase in the TV weight from just the TV alone was 720#. As measured/calculated at the scales, my TT weight was just under 6000#. So it would seem that a number for tongue weight of 12% of GVWR, assuming weight distribution dialed in, is pretty close. I should say that the tongue weight included the weight of the WD hitch bars, but the hitch head was included in the TV only weights.

And yes, I would try to have 15-20% margin on GCVWR but I would be less concerned with GVWR as long as there was good margin on GCVWR and the WD hitch was set up right. "Less concerned" doesn't mean don't worry about it, but if I had only a little margin I wouldn't be too concerned.

Al


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