Community Forums

Desiday · 11-15-2020, 04:22 PM

So I’m cruising down I95 from Harrisburg,PA to the Keys, towing my Jeep in my 43 foot motor home with a 475 hp Cummins. I have my cruise control set at 60mph. The tach is reading 1600 rpm. I’m getting passed by other RV,s (and everyone else) like I’m going backwards. I have that setting strictly to conserve fuel. BTW, I haven’t touched my brakes since PA! I’d love to go 70 like everyone else, but how much more fuel would I burn? What is the “sweet spot” with a rig like mine. I think I was passed by a little old lady on her way to church!

rk911 · 11-15-2020, 04:30 PM

a little repeat experimentation should answer your question as the answer is different for each rig. us? well, we want to get where we're going so we keep our speed at 68 or the speed limit whichever is lower. over 5-seasons, all of it towing our 4-dr Jeep, we've averaged 5.2 mpg. individual segments range from 6.8 down to 4.3 mpg.

Mr Ted · 11-15-2020, 04:33 PM

Quote:

Originally Posted by Desiday

So I’m cruising down I95 from Harrisburg,PA to the Keys, towing my Jeep in my 43 foot motor home with a 475 hp Cummins. I have my cruise control set at 60mph. The tach is reading 1600 rpm. I’m getting passed by other RV,s (and everyone else) like I’m going backwards. I have that setting strictly to conserve fuel. BTW, I haven’t touched my brakes since PA! I’d love to go 70 like everyone else, but how much more fuel would I burn? What is the “sweet spot” with a rig like mine. I think I was passed by a little old lady on her way to church!

If everybody is passing you then you are obstructing the flow of traffic and are "That Guy" and should not be worrying about a few gallons of fuel.

twogypsies · 11-15-2020, 04:37 PM

With our 40' diesel motorhome we usually drove 62-65 mph and yes, it makes a difference.

Something that DIDN'T make a difference was driving with a full fresh water tank. Same mileage either way.

Cousin Ed · 11-15-2020, 04:55 PM

Desiday your post brings to my mind:
We drive a $ 400,000.00 RV towing a $ 50,000 car and are looking for a free place to stay!
I drive about 65 mph all the time and my average is 8.1 mpg (not counting generator or Aqua-hot)

Granite17 · 11-15-2020, 04:55 PM

We have a 2019 Dutch Star 4018 450 Cummins and cruise about 67 pulling a GMC Canyon pick up. 20,000 miles on the coach and overall average is 6.8 mpg.

traveldawg · 11-15-2020, 06:50 PM

Quote:

Originally Posted by Mr Ted

If everybody is passing you then you are obstructing the flow of traffic and are "That Guy" and should not be worrying about a few gallons of fuel.

I'd have to agree with Ted about being "that guy". 60 seems a bit slow. I hope you stay in the right land all the time on all your highways. Too many slow RVs seem to like the middle lane (too many truckers these days too) - all they do is impede traffic - even at 65 mph.

Our slowest speed on interstates is 64 mph. 66 is better and we do that a lot. And even then we are in the right hand lane. Going through cities and high traffic areas I pick the second from the right lane and flow with the traffic so as not to be "that guy".

yep - fuel mileage suffers but I think the safety factor is more important. I don't need some wild driver running up my tail while they are weaving and using their cell phone.

Do like Cousin Ed - save your money for extra fuel by staying at WalMarts.

jacwjames · 11-15-2020, 07:04 PM

I drive with the flow of traffic and average about 8 mpg pulling a Jeep GC.

I have done trips testing to see if there was a significant improvement if I drove ~60 mph, it didn't seem to make a difference but probably took years off my life.

RDupre · 11-15-2020, 07:32 PM

My wife and I purchased our first MH about 2 months ago, a 2020 Berkshire 39A with a 360 HP Cummins Diesel. We just returned from a trip to Nashville from S. Louisiana. I gererally drive about 63-65 mph. My wife does half the driving and she has a heavier foot than me, driving 70 mph. I was pleasantly surprised that we averaged 9.8 mpg including the 8 kw gen. and a tow vehicle. This MH makes better milage than my 2017 F-250 diesel pulling my old 40 ft Fifth Wheel.

wolfe10 · 11-15-2020, 07:35 PM

For a fact-based look at what affects MPG as well as speed expectations on grades:

https://www.prevostcommunity.com/PDF...%20economy.pdf

Xmcdog · 11-15-2020, 07:39 PM

Quote:

Originally Posted by RDupre

My wife and I purchased our first MH about 2 months ago, a 2020 Berkshire 39A with a 360 HP Cummins Diesel. We just returned from a trip to Nashville from S. Louisiana. I gererally drive about 63-65 mph. My wife does half the driving and she has a heavier foot than me, driving 70 mph. I was pleasantly surprised that we averaged 9.8 mpg including the 8 kw gen. and a tow vehicle. This MH makes better milage than my 2017 F-250 diesel pulling my old 40 ft Fifth Wheel.

That pretty good fuel mileage especially with a new coach.
Congratulations on you new coach. Sounds great.

grindstone01 · 11-15-2020, 07:45 PM

I drive 60 MPH all the time whether on my motorcycle, pickup, hauling my fifth wheel, or hauling grain in a semi. This is a product of learning to drive during the 70's when the speed limit was 55 nation wide, I just feel comfortable at the speed, besides, what is the rush, kick back and enjoy the drive. A couple of years ago, I did have a front tire blowout at 55 MPH while hauling my fifth wheel, and I was sure glad I was not going any faster. My rig still jumped into the passing lane and the wheels on one side lifted off the road.
One more advantage, I have only had 1 traffic ticket in my life and that was in 1973, driving slow is synonyms with driving safe. Fast drivers always have heart burn over that statement, but the facts are on my side due to having better control.

My 2018 Chevy Duramax got 13.2 MPG on my last trip 3 days ago of 750 miles and my rig scales at 27,000 LB (doing 60 MPH).

Rollin101 · 11-15-2020, 07:59 PM

Quote:

Originally Posted by grindstone01

I drive 60 MPH all the time whether on my motorcycle, pickup, hauling my fifth wheel, or hauling grain in a semi. This is a product of learning to drive during the 70's when the speed limit was 55 nation wide, I just feel comfortable at the speed, besides, what is the rush, kick back and enjoy the drive. A couple of years ago, I did have a front tire blowout at 55 MPH while hauling my fifth wheel, and I was sure glad I was not going any faster. My rig still jumped into the passing lane and the wheels on one side lifted off the road.
One more advantage, I have only had 1 traffic ticket in my life and that was in 1973, driving slow is synonyms with driving safe. Fast drivers always have heart burn over that statement, but the facts are on my side due to having better control.

My 2018 Chevy Duramax got 13.2 MPG on my last trip 3 days ago of 750 miles and my rig scales at 27,000 LB (doing 60 MPH).

I agree with you and it doesn’t make any difference if you’re driving 60 or 70 most [Moderator Edit] are driving 80-90 or more. Interstate speed limit is 45-70 so if you’re doing between those speeds you are a LAW abiding citizen. What part of speed LIMIT do people not understand. Lackadaisical speeders, texting, talking on phone, eating is what gets people killed. They get in an auto and think they’re 10 ft tall and bullet proof, but in reality they’re just self centered egotistical jerks that think they’re the only ones that should be on the road.

Crasher · 11-15-2020, 08:00 PM

The most important speed to drive is the one you are comfortable with. The speed that you feel you are in control for any event. Do not under any circumstances drive at a speed others want to to drive. You are the one responsible for your safety. Driving 60, as long as the transmission is in 6th gear, will get you better fuel economy that driving 65 or 70. If driving 60 on the interstate upsets some drivers, it's their problem, not yours. As long as there is a second or third open lane for others to pass you, you are not "That Guy", they are "Those Guys". Be safe and enjoy your RV.