SAFE TOWING SPEED

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erichardson

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Joined
Nov 10, 2014
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10
So, We do not have the fiver yet, as I mentioned earlier, we are still in the very early stages of shopping but while traveling this week I noticed some fivers pulling at speeds around 70ish, and others seemed to barely moving, maybe 55-60ish. Is this due to safety or to fuel consumption? I didn't notice anything particularly different in the trucks and fivers, just a newbies general observation.  Thanks  for the time in advance. The posted SL was 70...
 
Trailer tires (ST) are rated at 65 mph MAXIMUM.  That means that if you tow consistently at 65 mph, you are pushing your ST tires to their rated limit at all times.  Imagine turning your engine RPM over at red line all the time....

I've been towing about 25 years now, and have never had a tire failure other than a nail induced flat.  I've never had a blowout.  I tow at 55 MPH.  While I can't say definitively that towing at slower speeds is the reason for no failures, I tend to think there is a causal relationship.

At 70 MPH, you're asking for trouble.  Eventually, you'll get it.  JMHO, of course.
 
When I was towing a fifth wheel, the ?sweet spot? was 62 to 65. That?s where the truck RPM was in the range I wanted, fuel economy was reasonable, and it was overall just comfortable.
 
The safe towing speed depends on many factors, Tires is one (As someone posted some are only rated to 65 MPH some slower), Road conditions, and the ratio of tractor to trailer sizes, wind conditions, and more.

Some folks drive a Reasonable and proper speed (Thinking of the AT&T commercial where the two techs get stopped and the officer asks them if they know how fast they are going (55mph) and where are you going at such a reasonable speed).

Others,,,, Well,, Many Americans think the speed limit is for other people, It does not apply to them (Until, that is, it does, sometims with fatal results).
 
As said before, tires are an issue.  You can change out tires to LTs which are rated fot higher speeds.  What you will find when pulling a 5er is your comfortable speed.  Higher speeds will give poorer mileage and for me mores stress.  I think my rig performs better in the 62mph range, but I feel a whole lot less stress at 55 to 58.  Small difference, but just feels safer and in more control.  It really won't take many miles before you figure that out for yourself.  I just don't want to take a chance of an accident.  I don't want anyone to suffer because of my ignorance and you stand to sustain alot of damage to your rig if you blow a tire.  Life is short, make it last longer by going slower.
 
As others have said, the ST (Special Trailer) tires used on most trailers are limited to 65 mph, though many drivers ignore that. But fuel economy is a major factor too. Wind resistance increases with the square of the speed, so even a couple more mph can have a significant effect on mpg. Slower is better for mpg.

Lastly, speed is always a negative factor if something does go wrong, whether with your rig or the traffic around you. With a large trailer in tow, you cannot maneuver or stop anywhere near as well as with a car, so it makes sense to be more cautious.
 
along with safe towing speeds you need to be aware of the legal towing speeds.

check you state for the laws regarding towing speed, and also be aware of other states towing speed laws.

In California and many other states the maximum speed of any vehicle towing anything is 55 MPH.

as a general rule of the road watch the speed of gasoline tanker truck drivers, they have GPS monitors in most of those trucks and if they exceed the legal speed limit they will be fired.

here is a list of trailer laws......http://www.onlinetowingguide.com/pdfs/StateTowingLaws.pdf
 
There are many factors that would go into the answer to this question. Your skill, the balance and set up of the rig, and most important the conditions. When we purchased the fifth wheel last year I was not aware of the speed limitations on the tires being 65. That was learned from other discussions on the forum. At the time I was pulling around the 70 MPH range. Never above that.The rig pulled fine but he stress level with traffic was much higher. After learning about the tire issue I lowered that speed to the 62-65 range leaning towards the 62. What I found was an increase of about 2 miles to the gallon. Much less stress on the driver. In many cases cruise could now be used and the truck is not working as hard. In heavy traffic as before I slow down and let the folks pass me by. I always leave plenty of room in front which means I have JA cut in front of me in heavy traffic but what can you do. Bottom line is if you are feeling stressed at the speed your driving then you are going to fast and need to slow down. That is my rule of thumb and what I use for an indicator.
 
Frizlefrak said:
Trailer tires (ST) are rated at 65 mph MAXIMUM.  That means that if you tow consistently at 65 mph, you are pushing your ST tires to their rated limit at all times.  Imagine turning your engine RPM over at red line all the time....

I've been towing about 25 years now, and have never had a tire failure other than a nail induced flat.  I've never had a blowout.  I tow at 55 MPH.  While I can't say definitively that towing at slower speeds is the reason for no failures, I tend to think there is a causal relationship.

At 70 MPH, you're asking for trouble.  Eventually, you'll get it.  JMHO, of course.

Same here I tow at 55-60 MPH range and never experienced a sudden blow out or tire failure even with China Bomb tires. I get awesome MPG's and when I hitch up to the trailer I'm not in any hurry to get anywhere. I hitch up to relax not hurry. If anyone wants to go faster just go around me.
 
Will agree, we have slowed down, we used to travel up around the 70mph, now we are at 55-62mph and much happier.  Rough interstate highways were the main reason, just much more in control when you hit trouble at 55 vs 70, again, just our perspective though.
 
When trailering all things must be considered.  Tires are certainly a consideration and an important one.  As one above stated the stress on the driver and passengers is also very important.  But also consider the possibilities when encountering a bad situation such as getting cut off by a crummy driver or a blow out or an animal on the road or a pot hole or whatever, the difference between 70 mph and 55mph during these times is tremendous.

Because I am cheep and very safety oriented I drive double nickels when towing.  I have never been subject to a tire blow out nor have I ever even had a close call with any road hazard.

Do the math sometime.  When you consider the time spent getting up to higher speeds and the time spent slowing down from high speeds and all the time in stop and go traffic, do you gain more than a couple of minutes in a days driving?

Is driving the higher speeds really worth the cost?  If it is don't drive behind me, you'll get really frustrated!
 
Mopar1973Man said:
Same here I tow at 55-60 MPH range and never experienced a sudden blow out or tire failure even with China Bomb tires. I get awesome MPG's and when I hitch up to the trailer I'm not in any hurry to get anywhere. I hitch up to relax not hurry. If anyone wants to go faster just go around me.

I'm with Michael ..... when I have my RV hooked up, it's one of the few times in my life I'm not on a deadline, and I take advantage of that.  No hurry.  Anyone thinks I'm going too slow is welcome to pass.
 
We tow between 55 and 65 mostly because of fuel mileage not tire speed rating, our tires are rated at 75 not 65. Our trailer is stable at 75 but we prefer slower speeds maybe it's age  ;D

Denny
 
We tow between 55 and 65 mostly because of fuel mileage and our toad is not supposed to be towed over 65 mph or the warranty goes in the toliet. Our tires are also rated at 75.

My engine also has a governor and she sits right be side me!
 
I tow at 60 mph in tow/haul mode.  I have had two TT tire failures, one at 30 mph in a nice paved construction zone.

Perhaps my tire failures were related to too much sitting time and not enough rolling time.
 
Lowell said:
I tow at 60 mph in tow/haul mode.  I have had two TT tire failures, one at 30 mph in a nice paved construction zone.

Perhaps my tire failures were related to too much sitting time and not enough rolling time.

How does traveling in tow/haul mode affect your mpg?
 
TheNewhalls said:
How does traveling in tow/haul mode affect your mpg?

Tow haul mode locks the tranny out of over drive and changes the shift points which is great for towing performance and aiding in keeping the tranny temps down, but in so doing sacrifices some mpg.  I do not believe the hit on mpg is significant enough to not use tow haul mode
 
TheNewhalls said:
How does traveling in tow/haul mode affect your mpg?

I don't know how much it affects it.  I tow in the mountains of Arizona.  If I don't use tow/haul, there is more up shifting and down shifting than I am comfortable with.  I generally get 9-13 mpg towing depending on direction of travel and headwinds.  Going from the Phoenix area to the White mountains, I get about 9 mpg as it is a climb of 7000 ft over 250 miles.  Coming home, I get 12-13 mpg.
 
Lowell said:
I don't know how much it affects it.  I tow in the mountains of Arizona.  If I don't use tow/haul, there is more up shifting and down shifting than I am comfortable with.  I generally get 9-13 mpg towing depending on direction of travel and headwinds.  Going from the Phoenix area to the White mountains, I get about 9 mpg as it is a climb of 7000 ft over 250 miles.  Coming home, I get 12-13 mpg.

Same here.....the mountains are steep, and the grades are long.....without tow/haul it would hunt gears continually.  Any fuel mileage cost is negligible, as mileage is going to suck no matter what pulling in the mountains.  I got 8-9 avg with my old gasser, and about 13.5-14 with the Cummins.  Besides.....fuel is cheaper than transmissions....
 
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