Mileage towing a 337RLS?

Dale G

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Jackson, MO
I have a 2021 Ford F-350 SRW CCSB 4x4 Lariat Ultimate with 3.31 gears and the 6.7 diesel and I am currently towing an Imagine 2670MK, which weighs 8100 when we are fully loaded, and I get in the upper 11’s to lower 12’s towing at 70mph. I am getting 20 to 22 not towing at 70 to 75mph. This winter we are thinking of selling the Imagine and buying a Reflection 337RLS. What kind of towing mileage is everyone getting towing this camper with a similar truck?

Thanks for the info,
Dale
 
Generally speaking, since everyone tends to drive differently and trucks are different, you can probably expect between 8-10 mpg. Depending of course on wind, travel speed,
rate of ascent/descent, trailer weight, etc.
 
I have a 2021 Ford F-350 SRW CCSB 4x4 Lariat Ultimate with 3.31 gears and the 6.7 diesel and I am currently towing an Imagine 2670MK, which weighs 8100 when we are fully loaded, and I get in the upper 11’s to lower 12’s towing at 70mph. I am getting 20 to 22 not towing at 70 to 75mph. This winter we are thinking of selling the Imagine and buying a Reflection 337RLS. What kind of towing mileage is everyone getting towing this camper with a similar truck?

Thanks for the info,
Dale

One data point… I have a 2019 F-250 Lariat ultimate with 3.55 axles, similar to yours, and I tow a 303RLS, which tends to run 800-1200lbs lighter than the 337. With the 3.55 my truck has a sweet spot for towing mileage around 65-67 mph, I think the 3.31 would move that to about 72-74, until weight becomes a factor. Over the past year and 6000 miles, criss crossing the eastern US, I have seen 9.9-11.3mpg, depending on wind conditions, usually between 65-72mph. I don’t think the 337 would be much different, it is only marginally heavier and has an almost identical w ind drag signature, same height and width, and identical front cap.

Every report I have seen on the 2021 with a 6.7 and the 10 speed says the power is as good or better and the mileage is slightly better, than mine with the 6 speed torque shift.


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I would expect you'd get 11 mpg.

I have a 323BHS and my old 7.3 F250 with a tuner gets 20 mpg on the highway. Put the trailer behind it and it gets about 11 mpg.
 
I have a 2020 F350 CCSB 6.7L w/3.31 rear.

I tow my 337RLS @ 62-65 mph. I get between 10-12 mpg, depending on headwind or tailwind.

It usually stays in 10th gear and occasionally drops to 9th gear but unless I look at which gear it’s in I don’t notice it.
 
Generally speaking, since everyone tends to drive differently and trucks are different, you can probably expect between 8-10 mpg. Depending of course on wind, travel speed,
rate of ascent/descent, trailer weight, etc.

I was hoping that 8mpg would be the worst mileage (headwind, climbing long hills). Towing my current camper I get up to 12.5 flat terrain and no wind so I figure I will lose about 1.5mpg with the heavier trailer and higher profile.
Thanks for the information,
Dale
 
One data point… I have a 2019 F-250 Lariat ultimate with 3.55 axles, similar to yours, and I tow a 303RLS, which tends to run 800-1200lbs lighter than the 337. With the 3.55 my truck has a sweet spot for towing mileage around 65-67 mph, I think the 3.31 would move that to about 72-74, until weight becomes a factor. Over the past year and 6000 miles, criss crossing the eastern US, I have seen 9.9-11.3mpg, depending on wind conditions, usually between 65-72mph. I don’t think the 337 would be much different, it is only marginally heavier and has an almost identical w ind drag signature, same height and width, and identical front cap.

Every report I have seen on the 2021 with a 6.7 and the 10 speed says the power is as good or better and the mileage is slightly better, than mine with the 6 speed torque shift.


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That is interesting that you talk about the sweet spot for mileage towing. With this trailer, in calm winds, I actually get a little worse mpg if I slow to 65mph or less. A lot of times I am getting the best fuel economy at 70 to 72mph. I have a feeling it is where the rpm falls at those speeds. When I get to 70 the engine rpm is right at its max torque and never down shifts out of 10th gear unless it is a long hill.
Thanks for sharing your information,
Dale
 
I would expect you'd get 11 mpg.

I have a 323BHS and my old 7.3 F250 with a tuner gets 20 mpg on the highway. Put the trailer behind it and it gets about 11 mpg.

That is pretty impressive with the 7.3. My dad had one and it never got that good of mileage. Must be a really good tuner program. I am thinking I should get 10 to 11 in perfect conditions and a good coat of wax to reduce wind friction :rolleyes:
Thanks for the info,
Dale
 
Last edited:
I have a 2020 F350 CCSB 6.7L w/3.31 rear.

I tow my 337RLS @ 62-65 mph. I get between 10-12 mpg, depending on headwind or tailwind.

It usually stays in 10th gear and occasionally drops to 9th gear but unless I look at which gear it’s in I don’t notice it.

I have noticed the same thing that it rarely downshifts. When I first bought the truck I was worried that it would be constantly downshifting and I would have to lock out the top gears, but that has not been the case, great engine, transmission, rear end combination. When we went from Missouri to Flagstaff this summer it very seldom downshifted even though it was pulling uphill most of the trip. Have you ever driven 70 to 72 to see what mileage you got at the higher speed?
Thank for sharing your information, your combination is almost exactly what mine would be. Now I just need to sell my current camper after our last trip this fall.
Dale
 
To play devils advocate for those who drive their trailers over 65, the Goodyear tires are only rated to 65mph. Just sayin’


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Kevin & Deb. 2021 Reflection 320 MKS
2018 Ford F-350 Diesel SRW Platinum
 
To play devils advocate for those who drive their trailers over 65, the Goodyear tires are only rated to 65mph. Just sayin’


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Kevin & Deb. 2021 Reflection 320 MKS
2018 Ford F-350 Diesel SRW Platinum

The Goodyear Endurance have a rating of 117/112N which the N is the speed rating which Goodyear says is 87mph. The Goodyear website as well as etrailer.com confirms the N is for 87mph.
Dale
 
To play devils advocate for those who drive their trailers over 65, the Goodyear tires are only rated to 65mph. Just sayin’


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Kevin & Deb. 2021 Reflection 320 MKS
2018 Ford F-350 Diesel SRW Platinum

Which Goodyears are you referring to? You may want to recheck those figures.
 
My GY Endurance ST225/75R15 load range E has a speed rating of 81 mph.

Thanks for educating me. I was going if the Goodyear tire guide provided to me when we bought the trailer not what was listed on the tires. Probably will still top out no more than 70. Still have to stop the 7 ton following me[emoji16]


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Kevin & Deb. 2021 Reflection 320 MKS
2018 Ford F-350 Diesel SRW Platinum
 
With my F350 and 337RLS combination I get just at or under 10mph driving 65mph. I guess I could push it faster but I feel safer at this speed and that's worth the extra couple gallons I have to pump.
 
Just towed a 337 around 900 miles with a Ram 2500 diesel, 70mph, and averaged 11.6 mpg. More tailwind than not majority of trip.
 
To play devils advocate for those who drive their trailers over 65, the Goodyear tires are only rated to 65mph. Just sayin’


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Kevin & Deb. 2021 Reflection 320 MKS
2018 Ford F-350 Diesel SRW Platinum


Or not...lol

Just Sayin'
 
I also get 11 miles per gallon with the duramax with 3.73 gears . I also keep my tow mode on all the time.


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