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slowmover · 12-03-2014, 12:25 PM

" . . I would be comfortable dropping from 22 mpg to say 18 mpg driving 55-60 mph. Thoughts?"

22-mpg down to 18 is 19%.

The largest U-Haul trailer (6x6x12) dropped my highway average from 24 to 18/19 mpg (loaded/empty) in two seven hundred mile roundtrips. Or, 25%. (30% is the reasonable expectation, so use for planning). This cargo trailer and pickup with bed topper were same height. THe combo, loaded, was around 13,000-lbs.

Tires were adjusted to spec and trailer was levelled using adjustable hitch head. Loading was optimized. 57/8-mph @ 1,725/50 and across the same major North American city on each of four legs. The route was Interstate, familiar, and each stop was chosen for FE compatibility. Etc. There is more to it than just the rig. Vehicle spec is major, but after controlling for climate and terrain (and then incidentals like traffic & weather) the trip plan is where the real money resides.

22-mpg down to 15+ is near 30%.

I understand folks want low RV travel costs. More can be done here than is usually realized and only part of that is fuel cost. The biggest consideration is number of nights aboard per year as that trumps putative fuel savings if the number is low. 30-nights per year times ten years is not even a full years worth of occupancy. One can, IOW, spend two-three years building something that in no way justifies the time and energy.

One can reduce total annual miles driven and then drive at a higher level of skill. Even with my 65' 18,000-lb combination I proved to myself that I could underwrite 5000 miles of annual vacation travel by being strict in discipline for annual reduced solo miles. And I was already doing well in that regard. Plannng the normal errands pays off. A 20% improvement in my case over an 1,100-mile test.

Start with the annual fuel bill (gallons and dollars). Context is everything. An existing RV platform, optimized in mechanical and safety issues, combined with a good choice of tow vehicle (that best for solo use; the vast majority of miles annually) is the way through the maze.

A VW Jetta TDI pulling one of the smaller travel trailers will stay in the 20's without a problem. As will others. Start with a clean sheet of paper for examination. Were I to use that U-HAUL trailer to mod (and it is an excellent design & build; details matter) a nosecone, bellypan, suspension/brake upgrade and a folding "trailer tail" would be more than enough work. Interior fitment requires some engineering, and ignorant choices can make a bad [dangerous] trailer.

CASITA, SCAMP, OLIVER are nice. I might go with the longest BIGFOOT were I replacing my aluminum palace (even though it isn't "aero"). This current rig currently averages 15+ for Interstate travel on non-hilly terrrain. I knew ahead of time what was needed to do this, and was already experienced [lifetime] in much of it. KamperBob has around the same mpg average with his SCAMP 5'er behind a truck not unlike yours.

The goal is to go camping. Hunting, fishing, what-have-you. I'll argue the corner that using an existing platform is the way to go. Trip plan, mechanical issues and solo driving discipline will underwrite vacation fuel bills.

Cast a wide net.

.

12-03-2014, 12:25 PM	#11 (permalink)
slowmover Banned Join Date: Oct 2009 Location: Fort Worth, Texas Posts: 2,442 2004 CTD - '04 DODGE RAM 2500 SLT Team Cummins 90 day: 19.36 mpg (US) Thanks: 1,422 Thanked 737 Times in 557 Posts	*" . . I would be comfortable dropping from 22 mpg to say 18 mpg driving 55-60 mph. Thoughts?"* 22-mpg down to 18 is 19%. The largest U-Haul trailer (6x6x12) dropped my highway average from 24 to 18/19 mpg (loaded/empty) in two seven hundred mile roundtrips. Or, 25%. (30% is the reasonable expectation, so use for planning). This cargo trailer and pickup with bed topper were same height. THe combo, loaded, was around 13,000-lbs. Tires were adjusted to spec and trailer was levelled using adjustable hitch head. Loading was optimized. 57/8-mph @ 1,725/50 and across the same major North American city on each of four legs. The route was Interstate, familiar, and each stop was chosen for FE compatibility. Etc. There is more to it than just the rig. Vehicle spec is major, but after controlling for climate and terrain (and then incidentals like traffic & weather) the trip plan is where the real money resides. 22-mpg down to 15+ is near 30%. I understand folks want low RV travel costs. More can be done here than is usually realized and only part of that is fuel cost. The biggest consideration is number of nights aboard per year as that trumps putative fuel savings if the number is low. 30-nights per year times ten years is not even a full years worth of occupancy. One can, IOW, spend two-three years building something that in no way justifies the time and energy. One can reduce total annual miles driven and then drive at a higher level of skill. Even with my 65' 18,000-lb combination I proved to myself that I could underwrite 5000 miles of annual vacation travel by being strict in discipline for annual reduced solo miles. And I was already doing well in that regard. Plannng the normal errands pays off. A 20% improvement in my case over an 1,100-mile test. Start with the annual fuel bill (gallons and dollars). Context is everything. An existing RV platform, optimized in mechanical and safety issues, combined with a good choice of tow vehicle (that best for solo use; the vast majority of miles annually) is the way through the maze. A VW Jetta TDI pulling one of the smaller travel trailers will stay in the 20's without a problem. As will others. Start with a clean sheet of paper for examination. Were I to use that U-HAUL trailer to mod (and it is an excellent design & build; details matter) a nosecone, bellypan, suspension/brake upgrade and a folding "trailer tail" would be more than enough work. Interior fitment requires some engineering, and ignorant choices can make a bad [dangerous] trailer. CASITA, SCAMP, OLIVER are nice. I might go with the longest BIGFOOT were I replacing my aluminum palace (even though it isn't "aero"). This current rig currently averages 15+ for Interstate travel on non-hilly terrrain. I knew ahead of time what was needed to do this, and was already experienced [lifetime] in much of it. KamperBob has around the same mpg average with his SCAMP 5'er behind a truck not unlike yours. The goal is to go camping. Hunting, fishing, what-have-you. I'll argue the corner that using an existing platform is the way to go. Trip plan, mechanical issues and solo driving discipline will underwrite vacation fuel bills. Cast a wide net. . Last edited by slowmover; 12-03-2014 at 01:10 PM..