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EcoModding Lurker
Join Date: Nov 2008
Location: TEXAS
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Just came across this thread. As a third-generation travel trailer owner I'm always curious to see others numbers, hear of their experiences. I show 17.77 mpg for the above posted numbers, as an average, and that seems good. On the other hand, what did the rig weigh?
1) Truck, solo and truck, loaded.
2) Trailer, empty, and trailer, loaded.
30 Trailer tongue weight, empty and loaded.
4) The weight of the rig, hitched and ready to travel?
This set of numbers is important to determining "good" versus "bad" in relation to other, similar, rigs.
I have a 7,400-lb truck and use it to pull an aerodynamic (relatively) all-aluminum travel trailer (not an Airstream). The trailer weighs about the same, and, when loaded, the whole rig weighs 15,700 to 16,100-lbs. On the flatland Interstates, this 61' combination achieves 15 mpg at 62 mph. 13 mpg on the secondary roads, where traffic, etc causes me to have to change speeds regularly cuts the mpg. I believe I have another one mpg to collect, but that will wait for more travel time and some mods.
The worst "aero" of that cargo trailer isn't the flat front and rear . . it's the height! Did the rest of you miss this? The nosecone was a great idea, and I enjoyed reading of your fab work.
Andy Rogozinski (of Inland RV, Corona, Ca) pulled a mid-20's foot Airstream to over 110 mph, documented, back in the early 70's behind a BB Buick. The same tow vehicle couldn't get a flat-fronted U-Haul trailer past 90.
Andy Thomson of Can-Am RV in London, Ontario makes it a given that trading height for weight is a no-brainer (were one forced to that choice), and I agree. Flat front -- and TALL -- is terrible on the highway not only for economy, but for handling safety.
The second point is the lack of proper hitch rigging as a matter of safety AND of fuel economy. Please don't take my comments here as the kind of criticism that pervades the Internet, it is meant as being instructive.
Bear with me here.
I drive over 1,000 miles per week, and I see every kind of trailer you can imagine and then some. What I NEVER fail to see is incipient sway -- and the trailer type doesn't matter, big or small -- it "looks" like a bit of bouncing. But, closer study shows that the "bounce" isn't straight-line vertical, it is ALWAYS more pronounced to one side or the other. (The best reason of all to add shock absorbers to any trailer, the tires take a terrible beating; same goes for balancing the tires/wheels.) That "bounce" is the beginning of sway. And sway is such that even a trailer lighter than its' tow vehicle can overturn it. The tail wags the dog.
One hears, all the time, from those who "have never had a problem for X-decades" and I can tell you that they haven't ridden in the trailer. Why do you think that is illegal in nearly every state? Simple, they are likelier to turn over, and the reason for that is equally simple: 90% of rigs (not my statistics, but from the insurance industry) are improperly hitched; the rigging isn't corrected. The ride in a trailer, improperly-hitched, w/o balancing and shocks, is flat terrible. And, dangerous.
I'll bet the tongue weight on that trailer was at or above 500-lbs once loaded. Even my 3/4T Dodge owners manual states that I need weight-distributing hitch equipment above that point, NOT that the hitch can't carry three times that weight (it can, and then some), but that the dynamics of being hitched to a trailer have a deleterious effect on handling.
Youth, and/or determination can muster the strength necessary to overcome a poor-handling vehicle (try a 63,000-lb trailer full of 280F asphalt and a center-of-gravity above your head), but the extra work -- unnecessary and advised against -- eventually takes its toll on the driver. Who then loses the concentration that hyper-miling calls for. A one, two, strike. Safety first, economy second. It's a hand-in-glove situation.
The trailer must be level in itself (properly-loaded, with most weight on the axle[s], and the truck level in itself (with loading to ensure no tail-wag and STRONG securement against load movement [I had a good laugh the day I read of guy being killed by his IPod: he survived the car crash, but not the flying junk], then,
a weight-distributing, anti-sway hitch should have been used, where:
2/3 of the tongue weight is distributed to the tow vehicle, equally-spread between axles (no more than a 10% disparity); and 1/3 is distributed to the trailer axle[s].
This would have returned the front of the truck to it's original ride height (correct front end alignment, AND, slight nose down vehicle rake), REDUCED bounce and sway to a minimum (less steering input, less stress on suspension and tires of both vehicles) and given the driver a MUCH larger envelope of performance handling.
Coming to stop, upright, and un-hurt is no mean feat. And being able, on a maximum effort day to hit 600-miles before dusk (at a proper speed, with 10" stops every 2', and a 45-60" stop every 4') is honorable accomplishment.
A REESE "Strait Line" Dual Cam WD Hitch is the best entry level choice. Made for over 40-years. Anything less isn't worth it. There are better, but the price reflects it. The Dual Cam is the minimum.
Keep the left door shut, and the rig between the fenceposts.
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