Originally Posted by Haggar
More realistic is ~$20-$30 savings on a 1200 mile trip at 9-10mpg...
To me this number isn't worth it. Based on a different thread, it appears that very few tow more than 5K per year. So, a $150 per year savings is all you will net. In return, you need to be very consious of how you are loaded. Yes, I realize that $150 is significant, but like so many other discussions, if you are compromised by $150 per year, you are probably in the wrong sport.
A round trip to Canada is 600 miles, or $15. Make or break? I don't think so.
I find it odd that so many disregard my comments when I have actually done this. And with a reasonably light vehicle. Although I don't have pics of the other trailer, I actually had 2 different single axle trailers. Neither one worked well. But, at that time I didn't have a weight distributing hitch so balancing was super critical. I agree that with a WDH the balancing is not quite so sensitive.
If someone does this, I hope you have good success. But, at this time, I haven't read anything that there is significant savings or a good reason for it.
Lowering CG? Like Hagggar, I don't support a deck over trailer but rather a drop axle design. So, to lower your CG lower than that requires a more complex design that is likely to drag in many situations. I don't think that scrubbing around corners has a very significant effect on mileage. Also, most of us put a tool box on the front for straps, jack, spare stuff, etc. Now load this box up one time & don't the next and your dedicated mounting configuration is compromised.
Yes, 2 extra tires will impact mileage. I wonder how much it is. This may be your biggest savings.
As mentioned, wind resistance is the other big issue. But, when talking about jeeps, they are not very aerodynamic no matter how low you get them.
Since the concensus is to reduce weight and lower COG, does anyone have data to compare flat towing a specific vehicle versus putting it on a trailer? This would be a good indicator. Take your trail rig and flat tow it. Then stick it on a tandem trailer & check the mileage again. Since you are taking a vehicle on 4 tires and loading it onto a trailer with 4 tires, your difference would be COG and weight.
My suspicion is very little change.
BTW, what makes you think you will save 1 mpg?