Mountain towing

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Denna

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Joined
Nov 17, 2006
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2
I could use some help. We live in Denver Colorado and want to tow in the mountains, Estes Park and Rocky Mountain National Park. We have a Keystone Laredo 26RKS TT weight is 6185 capacity 3815 and tow with a 06 F-150 4X4 5.4 L V8 3.73 ratio 9300# tow rating. Hubby says it will tow just fine but it makes me a little nervous. I need to hear from people that have towed more than we have, which is not very much. I don?t care going up the mountain slow but it?s the coming down the mountain that worries me. I think we need to move up to an F250 diesel or the V-10. What are your thoughts?
 

Carl L

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Mar 14, 2005
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west Los Angeles
OK, consider your trailer weight.  With your dry weight plus the mfr's carrying capacity, you have a trailer gross vehicle weight rating (GVWR) of 10,000 lbs..  This is the number you should use to evaluate towability.

Your F150 has a tow rating of 9300 lbs, so you are already 700 lbs in a hole.  However, you want to tow in the Rockies as your primary destination.  For that we recommend discounting the tow rating some 20% to allow for the HP loss of your normally asperated engine of 3% per 1000 feet of altitude and to alow for long, long 6-8% up and downgrades.  Now your tow rating is 7440 lbs..

The short answer?  Get that F 250 with the 6.0L turbo diesel and the 3.73  You need its 12500 lb tow rating.    You both will be a lot happier with towing with it in your part of the country.
 

Scott Townley

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Joined
Feb 27, 2007
Posts
19
Location
Fullerton, California
I don't believe you loose hp on a diesel.  That number of 3% is for a gasoline engine.

I think that diesels only loose 1% for every 1,000 ft of elevation after 6,000feet.

Good luck  Scott..
 

Ron

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Jan 29, 2005
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Home is where we park it
I suspect that you are overweight which is not only unsafe but also illegal.  Could result in serious liability issues if in even a small accident. Check your GVWR, GCVWR numbers.  Don't guess get it weighed when loaded the way you plan to travel.
 

Carl L

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west Los Angeles
Scott Townley said:
I don't believe you loose hp on a diesel.  That number of 3% is for a gasoline engine.

I think that diesels only loose 1% for every 1,000 ft of elevation after 6,000feet.

That 3% is for normally aspirated engines.    A super-charged or turbo-charge engine will have a different and less severe altitude curve.  The actual value of the curve would depend on the altitude compensation on the blower.   

HOWEVER, that said transmission, drive train, and  especially, brakes figure into the picture.  An F-150 simply does not have the chops for those 5-10 mile long 6-8% grades that you encounter on western interstates much less the local roads.  Open a Mountain directory and read about I-5 at the Grapevine Pass or Siskyou Pass;  I-80 at Donner Pass; I-70 over the San Raphael Reef;  I-8 in the approaches to San Diego; and most hair-raisingly, I-90 over Lookout Pass.  The Grapevine has 2 runaway ramps.  Lookout has 3 as I remember.
 

Gary RV_Wizard

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Feb 2, 2005
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73,508
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At our Silver Springs FL home
I agree that an F250 or other 3/4 ton diesel is the best choice for pulling that size trailer. However, Denna's question was more focused on brakes than on getting up the grade, and there too the larger wheels & brakes on the 3/4 ion diesel will make a big difference. And they can add an exhaust brake as well, to give the service brakes some relief.

That 9300 lb towing capacity on the 150 assumes the truck has nothing in it but a full fuel tank and the driver - no optional equipment, no passengers (are you staying home?), no gear in the bed, and  not even a  trailer hitch installed. The actual capacity of your 150 when loaded for the road will be substantially less than 9300 lbs. And it assumes that the trailer will have great brakes of its own, since the truck is designed to stop only it's own GVWR, not the weight of the trailer too. Most trailers come from the factory with skimpy brakes, barely adequate for the weight when new and deteriorating after a year or two.

That trailer also has a 690 lb tongue weight when empty and probably 900-1100 lbs when loaded for a trip. That's a lot of weight for a 150 to carry, even with a weight distributing hitch. Odds are you are going to exceed the truck's rear axle capacity (GAWR) and maybe the GVWR as well, once passengers and gear are added to the tongue weight.

Denna, you call tell hubby for us that he is being terribly optimistic about the F150's capability and also that he is taking chances with his family's lives. Bite the bullet and get a F250 diesel - it is designed for those kinds of loads.  And I suggest adding an exhaust brake as well.  Besides, what man doesn't want to have a bigger truck?  ;) ;)
 
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