Trailer weight...again..check my math

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johnh

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Dec 10, 2006
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So I did a search... :)  and yes I am a newbie.

I am looking for a TT and I already have a Tow vehicle:  06 Suburban 2500 4x4 6.0L.

Now here's where it gets tricky, the stated Tow Weight (3.73s) is 7600#

The GCWR is 14,000, and the curb weight is 6074.
GCWR - Curb = 7926, I figure passengers (~650 lbs (me, wife, 4 boys and some stuff)), well that would leave 7276# which would mean I am already below the stated Tow Weight.

And if I read correctly, I should look for a trailer with no more than say .9 * 7276 = 6548#

And then using for the TT the GVWR of 6550 or less right?

I'd really like a Quad Bunkhouse setup, somewhere in the 25-30ft range, but most seem heavier than that..any recommendations?
 

Gary RV_Wizard

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The max tow capacity is given for a vehicle that is empty except for a full fuel tank, i.e. the curb weight of the tow vehicle. That's why it is largely a fiction - nobody tows with a vehicle that light.

So yes, your arithmetic is correct and yes, I would want to stay with a trailer GVWR that is no more than 90% of the remaining 7276 lbs. If it were a diesel I would be willing to stretch it further because of the better torque, but with a 6.0L gas engine it is better to stay light if possible.  Yeah, you would probably still get up the long hills, but you might get frustrated with the low speed and high temp gauge readings.
 

Carl L

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And if I read correctly, I should look for a trailer with no more than say .9 * 7276 = 6548#

And then using for the TT the GVWR of 6550 or less right?

Where do you plan to tow?  Eastern states or Mountain and Pacific Coast West?
 

johnh

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The current plan is mostly eastern states (I live in MI), so mostly midwest, with perhaps a trip to Florida or two.  I wouldn't rule out a trip out west someday though, but nothing in the near future...I do have relatives in AZ, but there's less mountainous routes that way.

Thanks guys..

One more question, looking at some potential TT, I've noticed quite a bit of variance in weight capacity, ie. the difference between Unloaded/Dry weight and the GVWR, the range seems to go from about 1200# to 2600#...would it be better to take the dry weight add in a number for say LP/Water and estimate rest of gear (clothes, food, bikes etc..), and say add 1500# to the UVW and keep that under the 6550 limit? 

What about adding power to the truck?  I have done a fair bit of engine tuning/modification on cars, I would imagine some easy mods that could easily increase the power...
 

2006F350

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Adding power to the truck won't make any change to your GCWR - that is a combination rating determined by by the mfg based on axle ratings, springs, engine, transmission, rear end gearing, etc., and cannot be changed except by the mfg.

The differences between dry and GVWR is mainly due to how much the trailer mfg is willing to invest in upgraded axles, frames, and the like (example, the could use 6000Lb rated axles, but if they can get by with 5000Lb and still give you a 1000 or so lbs of cargo capacity, that is the route they will probably take).

When figuring your loaded weight for traveling, the best practice is to weight the trailer, but if you are unable to, use the GVWR of the trailer in your calculations. You would be surprised at how easily that few pounds you think you loaded actually turn out to be at least twice the weight of what you thought you loaded. Our rule of thumb when we start to load is to actually multiply what we 'think' we loaded by 1.5 (100 pounds now becomes 150 pounds), and when we've weighed after loading, it is the norm that we end up closer to the 1.5 number than what we initially thought.

Best of luck in your decision, all we RV'er ask is that a fellow RV'er doesn't exceed their vehicles capabilites so we can all have a safe enjoyable experience.

Larry
 

Carl L

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johnh said:
The current plan is mostly eastern states (I live in MI), so mostly midwest, with perhaps a trip to Florida or two.   I wouldn't rule out a trip out west someday though, but nothing in the near future...I do have relatives in AZ, but there's less mountainous routes that way.

Out in Arizona you get into plateau country and the most interesting areas are up on the plateaus:  Grand Canyon, Navajo Rez, the Four Corners Country, Meteor Crater, Canyon de Chelly, and so forth.    The Colorado Plateau is 6000 feet in elevation.  That altitude gives a normally aspirated  engine an 18% loss in HP.

One more question, looking at some potential TT, I've noticed quite a bit of variance in weight capacity, ie. the difference between Unloaded/Dry weight and the GVWR, the range seems to go from about 1200# to 2600#...would it be better to take the dry weight add in a number for say LP/Water and estimate rest of gear (clothes, food, bikes etc..), and say add 1500# to the UVW and keep that under the 6550 limit? 

As Larry implied, the use of dry weight plus some intent to load light quickly becomes an exercise in kidding ones self.  Go with real numbers.  There are only two that count.  One is the actually scaled weight of the trailer loaded as if for a long time complete with water, propane, baggage, food, cooking gear, and goodies like awnings and extra batteries.  The other is simply to use the Gross Vehicle Weight Rating of the trailer which you can find on its DOT plate.  Frankly, I do not see how you are going to get the first number on a trailer that you do not own, so the GVWR is all that is available to you.  Use it.

>> What about adding power to the truck?  I have done a fair bit of engine tuning/modification on cars, I would imagine some easy mods that could easily increase the power... <<

And then you have to think of mods to add to the transmission, suspension, frame, and brakes.  Especially the brakes.  Going downhill on a 5 mile long 6% grade is even less fun than going up -- especially if you are on the dropoff side of a cliff hugging mountain road.

 
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