Your driving habits have as much to do with mileage as what you tow, and what your TV is.
I have towed a couple of HTTs with different tow vehicles. The Kiwi 17a was a 7' wide, 17ft, 3500# GVWR trailer. The X20E is an 8' wide, 4750# GVWR trailer. As smacdonald, the sweet spot is about 60 mph.
'03 Kiwi 17a with '00 Pontiac Montana, 10MPG at 60MPH no matter what conditions (never towed this combo in mountains)
'03 Kiwi 17a with '95 Suburban, 10MPG at 60MPH no matter what conditions, mountains, hills, wind, etc.
'03 Kiwi 17a with '03 Chevy Trailblazer, 12/13MPG flat, no wind; 9/10MPG in mountains; 10/11 hilly and/or windy
'13 X20E with '03 Chevy Trailblazer, 10MPG flat, no wind; 8MPG hills and/or wind
'13 X20E with '08 GMC Sierra, no data yet. first trip with this truck is next week. Yea!
BTW, keeping track of mileage is not something I do just to see how good I can get. I keep track of mileage because a drop in mileage is an indicator that something is wrong with the tow vehicle.
Originally Posted by smacdonald
When was the last time you saw a commercial truck/trailer combo without some additions to direct the wind over their trailers? It's not just a theory. Poke that hole as big as you can.
Sure I'll poke a hole it. Its all about practicality. Over the road trucks travel 100k miles a year. The ROI is real and tangible and is realized over a short period of time. How long will it take you or I to make up the money spent on mods to save fuel? 5 years? 10?
I'm a practical man and a realist. I have been towing camping trailers of some kind or other for over 20 years. I've read everything I can on this subject and have tried many different things that were reasonable to try. Mods will work, but will almost always yield marginal results. Yes, even at $5 a gallon. Maybe I can save $100 bucks a year in towing costs, but I'd rather spend the $500 intended for mods on fun things during a camping trip.
If the nose cap works for you, I'm not knocking that. Good for you. But you can't convince me that the marginal gains are worth it in the long run.
The best things you can do to save fuel is keep your tow vehicle properly maintained, change fluids regular, keep the PSI to the right levels in your tires, and maintain moderate speeds.