I was wondering if driving the interstate using cruise countrol would save much gas verses the slow down, speedup of going thru towns? My truck seems to have a sweetspot towing of 63 mph.

We traveled FT for 7 yrs. and took secondary/back roads as much as possible.Hate traveling Interstates. Boring, idiots that don't know how to merge, road surface beat up, heavier traffic etc.MPG difference.....never really noticed any. When pulling a 14K 13'4" wind sail we got 10.5--11.0 mpg regardless

I always get better mileage on interstate; for best use your foot not the CC.

I found going out East last summer (over 2000km round trip) that the answer was a big no for me. The sweet spot for my TV/TT combo was abt 95km/h (60mph). Going over that point even a little bit made a huge cost in mpg (just going up to 65mph was enough to make mpg go downhill by 25%. Driving thru Mennonite country between Watertown and Lake Placid and across US2 from Lake Placid to Bangor was great, the mpg was much lower, and yes there were small towns along the way with the occasional stop sign or traffic light, but we found the days went much quicker because the drive was much more interesting than on the freeways. The 401 in Ontario and AUT20 in Quebec were a much more boring (and slower feeling)ride even though they shaved a few hours off the return trip, I wished we had taken secondary highways on the return as well.I am in the process of planning next summer's big trip down the US East Coast (Ontario to Delaware, down the coast to Myrtle Beach, and back thru the mountains in VA/WV. I have been going out of my way to find scenic secondary routes, with the realization that keeping my speed below 60 will save me more money than the cost of an extra night in a KOA due to the extra time needed.

IMHO the consistent speed of the superslab (interstate) will give you better mpg results every time. Stop & go traffic yields dreadful gas mileage as you have to overcome inertia to get your rig up to speed time & time again. Years ago we were stuck in I-95 near Fredericksburg, VA and in that mile after mile of stop & go I could just about see the gas gauge going down.On edit: Is the scenery on the interstates more boring? Yes, no question. I try to plan trips to be a mix of interstate and secondary roads to keep things interesting.

I just finished a 2500 mile trip with a 2012 3.6 R Subaru towing a 2600 lb utility trailer.Now I know this is not an RV but this somewhat relative.Most of the miles were in California where the towing speed limit is 55.On the very rough Interstate highways where I was able to maintain 55 with cruise control I was getting 24 mpg.But on the very smooth state highways with towns about every 10 miles the mpg dropped to about 18.Most of the state highways were much less stressful and a much smoother ride.I drive 55 in California as I have out of state plates and do not want to be a selective enforcement victim.

Interstate vs. secoundary roads? | Good Sam Community

rhagfo
Explorer III
Oct 26, 2014
Never worked to figure it out. I tow mostly on secondary roads due to my location and preferred destination of the Oregon Coast. We did hit I5 north for a trip to Mt. Rainer this year. I needed to down shift far less often as there is no 45mph, or 35mph curves you need to slow down for.
I have also been caught in traffic backups on 101! Stop and go and lots of hills. That will make for some bad fuel mileage.
pianotuna
Nomad III
Oct 26, 2014
Hi,

I prefer the "red" roads. Interstates are definitely not my cup of tea.
john_bet
Explorer II
Oct 27, 2014
I drive the interstates to get out west,1800 miles one way, to family. We used some secondary roads this year and I found some were really rough. The 1800 mile trip usually takes me 5 1/2 days. We used more than usual secondary roads this year on our 50 day 7k mile excursion. I didn't follow mpg between the two but got about 11mpg for the trip.
Halmfamily
Explorer
Oct 27, 2014
Went to Atlanta yesterday to pick up our new fiver. Traveled interstates abbout 90% of the time with cruise set at 62. We averaged 12.1 mpg per DIC, that's pulling a 40' 12600 lb fiver and 143 miles each way. Would have been better but sat in 20 miles of stop and go traffic.

When traveling to the lake we use 2 and 4 lane roads with several long grades and average 10-10.5 mpg.
4aSong
Explorer
Oct 27, 2014
Old-Biscuit wrote:
We traveled FT for 7 yrs. and took secondary/back roads as much as possible.

Hate traveling Interstates. Boring, idiots that don't know how to merge, road surface beat up, heavier traffic etc.

MPG difference.....never really noticed any. When pulling a 14K 13'4" wind sail we got 10.5--11.0 mpg regardless

X2 - Agree with Old Biscuit.
Back or secondary country road are our 1st. choice and are more scenic. We never considered the MPG difference as we just enjoy what the secondary (country) roads have to offer over the interstates which are definitely boring.
Bedlam
Moderator
Oct 27, 2014
If you can drive secondary roads that do not have many speed zones through towns, you will get very good mileage. Otherwise the interstate will yield the best mileage unless you hit congestion.

Although I enjoy driving the secondaries more than freeways, I still work full time and have limited time off to get to desired destinations (typically plan for 500 miles days) that preclude long stretches on slower roads.
ktmrfs
Explorer II
Oct 27, 2014
4aSong wrote:
Old-Biscuit wrote:
We traveled FT for 7 yrs. and took secondary/back roads as much as possible.

Hate traveling Interstates. Boring, idiots that don't know how to merge, road surface beat up, heavier traffic etc.

MPG difference.....never really noticed any. When pulling a 14K 13'4" wind sail we got 10.5--11.0 mpg regardless

X2 - Agree with Old Biscuit.
Back or secondary country road are our 1st. choice and are more scenic. We never considered the MPG difference as we just enjoy what the secondary (country) roads have to offer over the interstates which are definitely boring.

x3. I'll take secondary roads even if it is longer. more scenic, neat stuff to see in small towns, nice places to stop, found many interesting towns, museums, restaurants, places to stay on backroads.

Travel about the same speeds either way, so doubt the fuel mileage is much different.
Bumpyroad
Explorer
Oct 27, 2014
D'OH, if 60 is the sweet spot for getting good mileage, you can certainly drive that in the right lane of the interstate. I do.
bumpy
myredracer
Explorer II
Oct 27, 2014
christopherglenn wrote:
Your best mpg would be constant throttle, bleeding speed on the up hills, recovering it on the down hills. Ok constant throttle everywhere but the down hills, less throttle there to keep from speeding.

X2. Theory and personal experience on better mpg agree for me on this.

Besides mpg, if you want to get somewhere farther and faster and with less fatigue, and a bit better mpg, a freeway/highway is the better option. I only use CC on flattish stretches and if there's no buffeting winds. I keep to max. 65 mph too.

I totally love towing our TT on the secondary roads and have towed in places like through the Redwood forests in Cal., along the Oregon Coast, around the Olympic Peninsula and Hwy 2 from Seattle up Stevens Pass and on to Spokane, all of which have a lot of twists and turns, hills, speed limit changes, stop and go, and can be quite windy in spots. I don't know for sure, but I'd guess we lose up to 2 mpg at the worst. I just let T/H mode do it's thing. For me, I find that secondary roads can be a lot more fatiguing and I can't/don't drive as far and I usually try to make it a more leisurely drive and don't drive with a heavy foot on the throttle.

When I can see ahead that I need to stop or slow down, I try to gradually slow down and then gradually pick up speed again. A bit easier on brakes, drivetrain and mpg.
Turtle_n_Peeps
Explorer
Oct 27, 2014
You best mileage will be at a constant speed. It takes a LOT of energy to get your rolling house up to speed just to slow down again. If mileage is your goal then the interstate is where it's at.