ok i'm trying to figure out how heavy a travel trailer i can legally tow, my truck is an 05 f150 fx4 5.4l with 3.73 auto 5.5ft bed, and tow package

 

Tough to answer. The heaviest trailer you can tow is one that won't exceed the GCVWR of your truck with all your passengers and stuff in it and the trailer weight combined. It also can't exceed the payload rating of your truck including hitch weight of the trailer, all you passengers and stuff in the box. Find these numbers and we can help more.

 

Almost every truck maxes out payload/GVWR well before the tow rating and/or GCWR. A piratical limit for 1/2 ton pickups is 7000 pounds. Average F-150 has 1400 pounds of payload. Take away 200 pounds for fuel, 500 pounds of family and gear inside the cab, and you are left with the 700 pounds of tongue weight which is the minimum 10% of a 7k pounds RV. Weigh your truck as equipped for camping. Subtract that number from the GVWR on your drivers door/B pilar sticker and divide by .1. You should be shopping RVs with dry or unloaded weight ratings (lies, lies, and more lies) under 5k pounds.

 

Not to nitpick but fuel is included in the curb weight and does not go against payload...although 25 gal @ 6.1 lbs is only a difference of 152 lbs
Unloaded weight rating is actual weight of the TT out the door of the factory.

 

Legally you can tow what you are tagged for not to be greater than 26,000 lbs. Then you have to take into account bridge weight formulas and tire capacity. GCWR means nothing to the law (only to ford on warranty issues), that being said I wouldn't tow much over 7K lbs with a 1/2 truck due to their fairly small running gear (IE the rear axle in a F-150 only has a working load rating of 4500 lbs at the ground).

In reality your biggest issue is not exceeding the GVW listed on the registration of the trailer and truck. IE Truck is 7,200 lbs, trailer is 8,000 you can't weight more then 15,200 lbs unless you bump your registered weight.

The DOT is looking for trucks that are over axle weights of 23,000 lbs give or take depending on the state and roads they are traveling.

Contrary to what people say, but no one can prove, is that insurance companies don't "drop you" or fail to insure you if you go over weight, they insure your truck and trailer, now if you really screw up and kill 5 people while driving they may drop you, but if you did that without a trailer they would still drop you.

 

Many manufacturer's don't actually weigh their trailers and guess at their dry or unloaded weights. Many list their dry weight as stripped out models without all the applianced installed too. If they told you they run every trailer over the scale before they ship it they are lying to you. Most trailer manufacturers ship out MSO and VIN numbers to the dealers who ordered the trailer before the trailer has even started production so the end owner can start the financing process.

This MSO is the pre-curser to the title and has the CWT or curb weight that the dealer and motor vehicle departments use and list as the dry weight.

Many trailer owners have been surprised when they actually take their trailer over the scale to find 200-1000 pounds of additional trailer weight there.

Ask any salesman and of course your F150 can haul that 30' three axle 5'er with a GVWR of 10-21k.

"Just take your time," they'll say. Yeah right.....

 

If you have to even ASK how heavy you can tow, you PROBABLY should be looking at a truck that's built for towing - like a Superduty. ALL 1/2 ton trucks, regardless of brand, are compromises.

 

Actually, any trailer built today MUST be weighed at the factory. This decal is usually in the kitchen area behind the counter door. You will find they are heavier then advertised but, now days you get the real trailer weight when you shop around.

 

That's great, BUT
None of the 4 we recieved this week were correct when we rolled them over the scales.

We just happen to have a scale next to where we unload them, so they get weighed as they roll across.

Sure they are supposed to be weighed at the factory. But again CWT on the MSO (Manufacturer's Statement of Origin)... the legally posted weight of the trailer is usually "determined" long before the trailer is even completely assembled.

 

Sounds like someone your are buying your trailers from is cheaping out. All the ones I've seen lately are dead on, that would be eclipse, holiday rambler, stellar and a few others, we were looking at high end trailers so I'd expect them to be more "honest" then some others.

 

It's not a matter of being honest or dishonest.

Because the MSO lists the weight as the VIN is assigned, and most manufacturer's CWT was determined before the trailer was even completed production... in fact usually as the frame is layed out.
The manufacturer's use a build sheet with the options that give them a precise weight of the options being installed and add them all up.
The problem is there are variances. Even weight changes in a sheet of ply or OSB depending on time of year can make a change of 100#'s or more ina larger trailer. Take also into account part supplies and changes to regular parts being used when supplies are not available and even a sink faucet can vary in weight. Add these all up and the trailers are close... approximate, but not precise.

Could the manufacturer wait and produce the MSO after the trailer was manufactured? Sure. In fact most of the manufacturers you list do.
The problem is today where customers want specific trailers made to them and not a stock trailer, a custom build is required. Doing this almost always requires financing. Financing companies want a VIN on the invoice from the trailer dealer.

Doing this requires an MSO and VIN to be assigned before the trailer has completed production to protect the manufacturer and dealer on a custom build to ensure the customer can indeed afford the trailer an has approved credit.

I'd bet the trailers you have seen by these "high end" trailers were all factory trailers with standard options and not custom builds.
I only ordered a standard trailer a couple of times a years. We order as needed. We specialize in custom orders which is the majority of our sales.
Our business and our customers always want something unique. This also allows me to not stock millions of dollars worth of trailers keeping us a profitable business. Sales are still up 23% over last year.