55 mph safe?

[andreasduess]

Our twins are 14 months old, the older brother is three. Twins sleep in travel beds on top of what will become their real beds when they're old enough, the older one sleeps on the dinette.

We just had new vinyl flooring laid, for ease of cleanups. We also keep a stack of army blankets at hand, we buy them from surplus stores. They cover the dinette during the day, the gaucho, they serve as picnic blankets, emergency duvets, everything.

At the end of the trip they go into the washer and drier. They last forever and forgive most anything.

[PharmGeek]

Those are excellent ideas!

[slowmover]

Originally Posted by PharmGeek

I think 60 will be right for me - I'm very conservative about driving believe me!!

My personal debate was 55 vs 65 - 60 is middle ground so there

I'll be watching mileage to indeed find a sweet spot

Good point switz

From experience: Use a range of 58 to 62-mph. 58 is the best fast fuel economy speed, and using 62 as an upper limit to approach a grade or get around someone even slower keeps numbers honest (fuel economy, and the like). The single exception to this is in passing on a two-lane. In that event, accelerating to full passing speed is done before moving into the oncoming lane . . thus the distance to the next town, etc, figures in. The penalty for fuel consumption can dictate whether it is worth it or not. At ten, sometimes twenty miles, it likely it not. One backs off and re-adjusts to the slower speed.

The records you keep ought to reflect climate, terrain and any large metro areas to traverse. A fuel cpm is also an indicator of vehicle wear. Find the fuel cpm average.

As to getting somewhere faster, departure times and controlling planned stops is where it counts (my income is dependent on these details; there are yet more layers). On any trip of up to 300-miles travelling faster is of no benefit, time-wise, and is contraindicated for cpm control, overall.

As 300-miles or three o'clock is a now-ancient RV maxim, use a planned itinerary (all stops) to make the most of your time . . it trumps travel speed (stupidities about "traffic flow", etc can be ignored) as the planned stops of fifteen-minutes every two-hours, and for an hour every four hours of driving (the fuel and lunch break) is the rhythm.

Learn to use the mirrors to advantage, and drop off your travel speed 5-8/mph when buses and eighteen-wheeler are going around you. Never hesitate to move to the left lane when four seconds from overtaking slower traffic . . there is no actual "right of way" for left lane traffic; the burden is on them, so to speak. Use it to your advantage as not to crowd up against others.

Planned stops, following distances, understood cpm penalties, etc, are where it's at. Travel speed is a filler, not the meat of the problem.

For those who say otherwise, the assumptions made about risk entailed is easily shot down. Braking distance is the golden standard . . and driver awareness is dependent on not only being rested, but in establishing good habits from the outset. Loss of control accidents have driver problems at center . . but assumptions about road signage, surface quality, etc, all play their part. GPS is a fallback . . check the published routing at start and end of trip planning the day ahead. One is only accomplishing a series of legs throughout the day. Set that, and the rest is easy.

A combined rig is work, so work in advance of departure to make driving as easy as possible.

.

[Pahaska]

Best speed depends somewhat on the sweet spot for your particular engine and gearing. Diesels are particularly picky about the best RPM.

With the Duramax, 55 mph is too slow, the transmission shifts down more often, and fuel mileage is not any better. About 62 mph seems about best and I get good fuel mileage with very few shifts. At 65, I lose about 1 mpg. I run about 62 except in city freeways where I disrupt traffic less by pushing it up to 65.

[PharmGeek]

really good info here you all....T- 3 weeks and I hope to begin putting it to good use!

Braking distance for me is critical...I commute every day 1 hour each way and I know that this is likely a huge risk for me...when I drive I keep significant distance and have avoided 2 accidents so far as a result. clearly this applies when towing 7K+ lbs

[perryg114]

Do some tests to determine what your real stopping distance is at 60 MPH with the trailer in tow. Compare this to the tow vehicle alone. Normally you would use the 3 second rule when not towing. Which turns out to be 263 ft at 60 MPH. This is taking your reaction time and the stopping distance into account. You measure time by counting as soon as a car in front of you passes a sign or bridge etc. When you pass that same object you stop counting. With a trailer you might want to double or triple that lead time between you and the nearest car in front of you. It you are going 70 MPH. Then the following distance becomes 308 ft. The nice thing about the 3 second rule is the safe following distance adjusts for speed.

Perry

[m.hony]

I had been towing at 55 to save gas. Last week I started going 60. It doesn't seem to use any more gas at 60. I know by previous experimenting that it does use more gas at 70. I might try 65 some time for comparison to 70 and 60. Driving 55-60 does not bother me at all. Everybody else can go around me while I am saving gas.

[perryg114]

Inland Andy said that putting an Airspeed indicator in the tow vehicle was a good way to stay at 55 MPH wind speed. It does not matter what the ground speed is. The drag is a function of the wind velocity squared.

Perry

[PharmGeek]

Originally Posted by perryg114

Inland Andy said that putting an Airspeed indicator in the tow vehicle was a good way to stay at 55 MPH wind speed. It does not matter what the ground speed is. The drag is a function of the wind velocity squared.

Perry

Interesting!! Never thought of it that way

[r carl]

Originally Posted by perryg114

Inland Andy said that putting an Airspeed indicator in the tow vehicle was a good way to stay at 55 MPH wind speed. It does not matter what the ground speed is. The drag is a function of the wind velocity squared.

Perry

I bet you could get one hell of a speeding ticket.

[Ag&Au]

Originally Posted by perryg114

Inland Andy said that putting an Airspeed indicator in the tow vehicle was a good way to stay at 55 MPH wind speed. It does not matter what the ground speed is. The drag is a function of the wind velocity squared.

Perry

OK,
This will measure the component of the airspeed that is parallel to your track. However since, unlike an aircraft, your trailer is attached to the ground, the component of the effective airspeed that is perpendicular to your track also will affect the total drag. This is because, among other things, the steering wheels must be turned into the wind to maintain the track on the road. This means all of the tires on both TV and TT will be rubbing sideways to some degree or another.

Also, this method of measuring speed fails to take into account the characteristics of the powertrain that make certain engine RPM more efficient that others.

So, in my opinion, as cute as it might be to have an airspeed meter in the tow vehicle, the cuteness would be the extent of its actual value.

Ken

[PharmGeek]

Originally Posted by Ag&Au

OK,
This will measure the component of the airspeed that is parallel to your track. However since, unlike an aircraft, your trailer is attached to the ground, the component of the effective airspeed that is perpendicular to your track also will affect the total drag. This is because, among other things, the steering wheels must be turned into the wind to maintain the track on the road. This means all of the tires on both TV and TT will be rubbing sideways to some degree or another.

Also, this method of measuring speed fails to take into account the characteristics of the powertrain that make certain engine RPM more efficient that others.

So, in my opinion, as cute as it might be to have an airspeed meter in the tow vehicle, the cuteness would be the extent of its actual value.

Ken

pedantic nerd challenge...I say that with admiration as a proud pedant myself..

(I have little/no physics expertise so I bow out of that debate )

[perryg114]

The Airspeed indicator will allow you to stay at a constant speed relative to the air and should allow you to get more consistant gas miliage. Yes there are second order affects but I was not trying to get to less than 1%. It is really not something I would consider. My V10 Excursion gets about 8 MPH driving hard and about 9 when I loaf along. There are other factors like the grade of gasoline, ethanol (evilnol) content etc that mess with your gas miliage. I think as others have stated that breaking the trip into shorter sections reduces the need for excess speed. We just got back from St Joe State Park in FL and I found myself driving a little too fast trying to get home before too late to unpack and get ready for work the next day. The trip was 441 miles. Less pressure makes for slower safer driving.

Perry

[Skater]

Originally Posted by m.hony

I had been towing at 55 to save gas. Last week I started going 60. It doesn't seem to use any more gas at 60. I know by previous experimenting that it does use more gas at 70. I might try 65 some time for comparison to 70 and 60. Driving 55-60 does not bother me at all. Everybody else can go around me while I am saving gas.

I've noticed with our F-250 w/6.0L diesel that if you stay at 60 mph for a moment, it'll shift into overdrive even while towing. So, I wouldn't be surprised if 60 mph in our rig is just as efficient - if not more so - than 55 mph. The only downside is that at 60 mph, it has to downshift to do anything, even a mild hill, whereas at 55 mph it will react faster to additional load because it doesn't need to downshift.

Your tow vehicle might do something similar, but possibly at different speeds. Just gotta tow with it a lot to find out.

[Ag&Au]

Originally Posted by PharmGeek

pedantic nerd challenge...I say that with admiration as a proud pedant myself..

(I have little/no physics expertise so I bow out of that debate )

I took a lot of physics. However the most valuable class I took was "How to Sound a Bit Like You Know What You Are Talking About, When You Really Have Know Idea" I think it was actually entitled, "Political Science 101" It was also offered in the Agriculture School as "Bovine Excrement Dispersal 301"

Ken

[PharmGeek]

Died laughing!!!!!

[BAB]

...I am "relearning" my towing skills with my new 2014 Ram 2500 4x4 Laramie with the Cummins 6.7L diesel. The 2012 Infinity QX56 I towed with over the past year (around 16,000 miles) was fantastic. It is an ENTIRELY different experience with the Ram. In particular, having so much torque, a turbo-diesel AND exhaust braking has required me to go back to basics. While many of the skills (and they ARE skills) are transferable, everything from TV length, mirrors, braking distances are different. The differences in shift points could not be greater, and even backing requires rethinking. So, I'd say that it's probably not a good thing to do specifics on "how to's" from speed to you-name-it. Hitch set-up, a now modified PP drop and tons of other factors weigh into this. Frankly, I am enjoying the challenge and love my new truck but it is most assuredly a very different experience.

[slowmover]

55 mph safe?

As I wrote above, do the work of planning in advance to lower the amount of work (mental) while on the road. And, to establish good habits from the outset. These are predicated on controlling costs . . and not just for the trip planned, but for the longest life of the vehicles concerned. So the daily details fall into a larger context. My wish is to understand the overall cost of living in this manner (from purchase to sale) so the costs of nights aboard is also related to travel speed however indirectly.

Safe is pretty much braking distance. Any need to maneuver sharply is contraindicated. I'd say that, for general purposes, that 45-mph is a speed that a decently hitched combination can deal with such changes from straight-line travel (pickups being lowest denominator). The ability to get to that speed -- time & distance -- is the "out" for which we plan as keeping the rig upright, lane-centered and aligned is basic.

Difficult winds & difficulties with road surfaces are all made easier with lower travel speeds. 60-mph is where, aerodynamically, wind resistance graphs upwards sharply. So travel costs are also on that line, and longest term costs as well. (If my TV didn't work well at 60 or slightly lower, I'd re-gear it as over a few hundred thousand miles the savings are at least a wash on fuel alone; tire and engine wear also figure).

Whatever the OP winds up doing long-term, the notes made over the first year or two -- when all of this is fresh -- will pay off long term. I like to be able to plan from any aspect of time and distance, be it daily, monthly or per 1000-miles. Etc. So, comfort in how it all seems to come together is what makes things automatic when another trip or move is planned. This, from doing this set of calcs on a daily basis running around the region (Eagle Ford), or from where do I want to be in three days so as to best plan today on other longer oilfield-related trips.

Choice of road, expected weather as well as load and traffic have to mix best to achieve an expected end. On TT journeys it is the mix of people along as well. Some discipline on their part can be learned, but I would like to emphasize that planning changes over a larger number of choices than just speed can be satisfying to all concerned, youngest to oldest.

As someone who grew up riding the backseat of a big American car pulling an aero aluminum trailer the memories are often not the planned high points . . it may have been a far distant thunderstorm moving across Nebraska with Dad explaining weather-phenomena from the aspect of a pilot. With further elucidation from Mom about her 19th-century grandparents gathering livestock in advance of threats as seen . . and we, in air-conditioned limitless 1960's America working from yet another set of choices.

Is 55mph "safe"? Sure . . but it's more a guideline than anything else (and learning to manage overtaking and passing traffic -- two different things -- is itself a challenge), so expand the playbook and be willing, within a framework, to make changes where hard and fast rules are explored.

.

[carl2591]

That i can believe.. my wife drove from NC with her mother to Glacier 2 summers ago as the MIL was working at Lake McDonald Lodge for the summer. (retired Liberian) She was telling me about being on a 2 lane road in montana with a 70 MPH speed limit.. That was how you know you are in the boonies.. There was not a lot of traffic and yes they did see the triples going the other way.

Originally Posted by Len n Jeanne

These data on traffic fatalities per state may be of interest. They are adjusted to show fatalities per 100,000 people, to level out the effect of state population size.

Montana (4th worst) has a 70 mph speed limit on the 2-lane windy mountain road we drove home on last week. They also allow triple-bottom towing: truck, trailer, boat. Just cuz it's legal doesn't mean it's safe.

Traffic Deaths by State - Fatal Car Crash Statistics

[carl2591]

that could be dangerous especially if you have a 15-20 MPH head wind and you are trying to only do 55 MPH wind speed you could be only going ground speed of 30 MPH .. that is dangerous and not legal on interstates. I understand the reason but that is, in my mind, a suggestion..

I do try to see which way wind is blowing.. If i am down wind i might bump speed up a bit and if head wind slow a bit. (this is not pulling a trailer i have a van with ladders on top so wind is a big deal)

Originally Posted by perryg114

Inland Andy said that putting an Airspeed indicator in the tow vehicle was a good way to stay at 55 MPH wind speed. It does not matter what the ground speed is. The drag is a function of the wind velocity squared.

Perry