Rear cap fuel savings

[jacknife]

Look at the semi trls alot have foldable extensions to reduce turbulance.

[wingnut60]

Have seen a lot of effort put into getting just tenths/mpg improvement for the truckers--if we drove hundreds of thousands of miles with a fleet of trucks, it does add up. For a fiver, don't think it could ever be proven to be worth the effort.
If it was that easy to get mpg improvements, every pickup towing a fiver would have an air foil on top...including mine. And stability with my setup isn't a problem.
Good conversation tho, never know when something might come up that makes a real difference.
Joe

[DieselGod]

I can tell you with certainty that air tabs don't work, and none of the above claimed 5.5% the key is in the wording "up to" 5.5% which includes 0. Big rigs with side plates and underbelly deflectors save about 4500/yr in OTR long haul trucks. Based on fuel price and the fact they put on more a year that 10 with your RV. You need an absolute ton of miles to see the decimal point increase in drag's effectiveness. I had bigger gains in fuel economy in my big rigs and in my RV simply by running Amsoil synthetic oil, not to mention reduced maintenance and drivetrain wear. Keep your air cleaner clean and run injector cleaner in those diesels, make sure your tires are up to pressure and all joking aside keep your rig clean and waxed and you will see point % gains again. There are no miracle cures for anything out there and the old adage that if it sounds too good to be true it is, there's a sucker born every minute, and a fool and his money are soon parted all bear truth sadly. It's all about it the little things you can do to add up to realitively small gains but gains none the less and they don't really cost much.

[wingnut60]

Just got to thinking...didn't all the old Shasta trailers have their version of the 'airfoil' on them?
Joe

[Wilber1]

Rear caps look great but I doubt the average RV'er could see much fuel savings from one if there are any to be had. They just don't rack up enough mileage to make much difference.

[IC2]

The now gone 33' Titanium had a rear cap and really looked nice. My fuel mileage was 12-13. The current 38' and heavier Montana doesn't and my fuel mileage is ta-da!! 12-13.

When I asked an honest (an oxymoron?) RV salesman why many premium 5ers no longer had the molded rear cap, his answer was money - the cost of manufacturing and the sell price, no other reason. Some do offer a rear cap at about a $2K adder which will, at current diesel prices, put 1000 gallons of fuel in the TVs tank, or figured at 13mpg, 13,000 miles

[renegade]

I ran one of the folding tail spoilers on my big rig for 450000 miles, just over 3 years and it saved me $800.00 in round numbers over the course of those 3 years. It cost quite a bit more than that to purchase, install and maintain. I no longer have it. The underbelly skirts on the other hand did help and surprisingly added stability in cross wind situations, probably by preventing air under the trailer from trying to lift it like ground effect skirting on a race car.