Gears, Speed & MPG

[Ron045]

Our first three trips were fairly local. Never got above 55 mph due to the roads and my inexperience. My gas mileage was right around 10 mpg.

This last trip was to FL and open interstate speeds were 70 mph. I stayed right around 65 mph... just fast enough not to get run over.

At 65 the TV did not want to go in 6th gear. It preferred 5th gear. Mpg's were between 7 and 8. I did notice if I backed down to 62 mph the TV would go into 6th gear.

How do you all handle high speed roads on a two lane interstate? At what point does my slower speed become dangerous to the cars and 18 wheelers flying by me and coming up quick on my rear?

Thanks
Ron

[FirstTracks]

Ron, I'm new to this too. Here in the West with rural Interstate speed limits of 80-85 mph the disparity is even worse. Furthermore, I've found that my TV tows much more efficiently at 75 mph than it does at 65-70. What makes me nervous, however, is the cheap Chinese tires installed by Forest River on my TT that have a speed rating of 65 mph, and show a manufacture date of 4/2014.

I've always believed that it's safest to drive at or near the flow of traffic, regardless of what a speed limit sign says. I also am starting to show some uneven wear on one of those tires. So, I have a 10 a.m. appointment today with a trailer alignment specialist. I'm then replacing those tires with some N-rated Goodyear Endurance for peace of mind. Thereafter I'll be staying closer to the flow of traffic at ~75 mph.

[Evereddie]

This will be an interesting thread.

[510Rick]

Yes prepare to become the villain . Folks in here are real touchy when it comes to speed .
As for what gear your seeing when towing depends on the grade. I personally would rather have higher but still safe RPMS that keep me in the sweet spot as far as power goes . I think its actually easier on the engine and transmission . If you wanted 20 mpg you should have picked a different hobby .

[jaherbst]

It's not how fast you go, but rather arriving safely and without incident!

Jack

[m35a2]

Originally Posted by Ron045

Our first three trips were fairly local. Never got above 55 mph due to the roads and my inexperience. My gas mileage was right around 10 mpg.

This last trip was to FL and open interstate speeds were 70 mph. I stayed right around 65 mph... just fast enough not to get run over.

At 65 the TV did not want to go in 6th gear. It preferred 5th gear. Mpg's were between 7 and 8. I did notice if I backed down to 62 mph the TV would go into 6th gear.

How do you all handle high speed roads on a two lane interstate? At what point does my slower speed become dangerous to the cars and 18 wheelers flying by me and coming up quick on my rear?

Thanks
Ron

Those other drivers also have a responsibility to adjust their speed, not just you. Drive the speed you are comfortable with and don't let faster drivers pressure you. A slower camper is not a danger to an attentive driver. Just relax and do your thing.

Just my .02.

[mwdilday]

Speed is your enemy when towing. Most ST tires have a max speed rating of 65 that should not be exceeded. I believe that unmanaged tire pressure and over speeding ST tires is the leading cause of blowouts. Check your tires max speed rating. 65 is fast enough for me. If your TV is hunting gears or RPMs are low you should go to a lower gear and leave it there. There is a RPM for your engine where you will get the most efficiency.

[Ron045]

Originally Posted by 510Rick

If you wanted 20 mpg you should have picked a different hobby .

It's not that I want 20. I just thought it was interesting that I went from 10 to 7 based on speeds that increased from 55 to 65.

[510Rick]

Originally Posted by Ron045

It's not that I want 20. I just thought it was interesting that I went from 10 to 7 based on speeds that increased from 55 to 65.

My apologies I sounded a little rude when I typed that .

Had to rewrite after I typed out my last response I reread your first post and I lean toward wind resistance being the enemy that was causing you not to get 6th gear. Usually for me I like to keep it down a gear where I have good power and am not over revving then engine .

[carlsbad]

The engineering answer: non linear equation.

Also remember that every engine has its own power curve, every trailer has its own surface area and airflow resistance dynamic, and you get mpg all over the board.

[ronheater70]

My tires are rated for 75 MPH.. I tow ranging from 60-65 MPH, typically in between.. Might speed up a little going down a hill, but in general my rang is 60-65. Most of our interstates are 70 MPH speed limits. Even if it were 80-85 mph speed limits, I would still do 60-65.
Its no different than pulling on a two lane road with a speed limit of 55 mph and suddenly coming to a steep hill and slowing down to 40 because of grade and load.

To the OP.. On my f150 ecoboost (and my ram 6.4 hemi) I have found on both vehicles that allowing it to go into a higher gear typically returns worse MPG for me when towing.. seems you need to have your foot in it more to maintain speed in 6th when you can let off a bit and let the rpms climb a tad in 5th and get better results... My experience anyway.

[wildcatter]

I tow a 5th wheel and sometimes I double a motorcycle trailer, I stick around 65-67 unless I have to pass someone (yes it does happen even at those speeds), I do stick to the right lane so i am not impeding traffic, they can go around me. the tires on my 5th is rated for 80, the tires on my MC trailer are rated for 75, I figure why push it. as far as the shifting that is normal for a gasser, the transmission can't maintain that speed and RPM in 6th. What really stinks is when you get to spot where the transmission keeps switching gears trying to find the one it wants to stick with.

[Jeff_and_Abby]

We really like doing between 55 and 62 MPH ... so we find ourselves a semi to follow, and sort of grab on at a polite and safe distance back. Most of the pro truckers notice that they have someone behind them who is paying attention and driving safe, and will do little things to make your life easier as well.

Unrelated - How did that TV commercial go, "It's not how fast you tow, it's how well you tow fast" ???

[JohnNJean]

We usually settle in around 62 to 64 mph and find it relaxing in that we're not constantly changing lanes to pass trucks - which are generally running about that speed. (The open road speed limit around here is usually 75.) My wife often comments about the "platoons" of cars that wizz past us often making some rather exciting lane changes.

I've noticed that a headwind costs me about 0.5 mpg and a tailwind gains me about the same. At faster speeds the drag curve gets really steep and an extra five or ten mph can really suck up the gas.

I usually just set the cruise and kick back. (BTW, I use the GPS speed as it seems more accurate than the speedometer). Recently, someone on this forum mentioned that they get better mileage by locking out 6th and sometimes 5th gear and I intend to try that next trip.

[LynnGlaze13]

Originally Posted by Jeff_and_Abby

Unrelated - How did that TV commercial go, "It's not how fast you tow, it's how well you tow fast" ???

I thought the exact same thing when I read the post!

[LynnGlaze13]

Originally Posted by Ron045

It's not that I want 20. I just thought it was interesting that I went from 10 to 7 based on speeds that increased from 55 to 65.

I would be surprised if you didn't see similar losses if you crank her on up to 75!

[darrenbrown]

Originally Posted by Ron045

Our first three trips were fairly local. Never got above 55 mph due to the roads and my inexperience. My gas mileage was right around 10 mpg.

This last trip was to FL and open interstate speeds were 70 mph. I stayed right around 65 mph... just fast enough not to get run over.

At 65 the TV did not want to go in 6th gear. It preferred 5th gear. Mpg's were between 7 and 8. I did notice if I backed down to 62 mph the TV would go into 6th gear.

How do you all handle high speed roads on a two lane interstate? At what point does my slower speed become dangerous to the cars and 18 wheelers flying by me and coming up quick on my rear?

Thanks
Ron

My F250 stays in 5th gear most of the time when towing. Its no problem for the vehicle, they are designed to shift into 6th when it needs to, as far as speed goes, I drive at a speed I feel comfortable with (usually at or 5 under the speed limit).Never be in a hurry when you are towing. I really don't care if other drivers like it or not. That's why they can pass me.

[kayo]

I am a bit surprised that no one mentioned anything about stopping! It is e thing to slam on the breaks of a vehicle in order to stop, but something else again when you have 8 tons of trailer that needs to also stop.

[amblt]

Originally Posted by Ron045

It's not that I want 20. I just thought it was interesting that I went from 10 to 7 based on speeds that increased from 55 to 65.

Aerodynamic drag increases as the square of the speed. Your drag will increase 4x for a 2x increase in speed, so your gas mileage will be reduced rapidly for what seems to be a moderate increase in speed. I'm sure the characteristics of your particular vehicle (torque and rpm curves, final drive ratio, etc), are equally important.

Cheers

[K4DCF]

I use tow/haul mode so never see 6th gear. This also lets the tranny build a profile for my trailer vs daily driving. I set the cruise control on 65 for interstates and let the truck do its thing. This keeps me in the flow of most traffic so I can make lane changes easily. As to stopping I have the exhaust break to help out the conventional breaks. I got 12MPG on my last trip. 5th wheel tires are rated to 75mph