# How Fast Do You Drive?



## NDKoze

*How fast do you drive (average)?*​
*Flat Land Interstate with 75mph speed limit?*

701623.88%653653.73%601420.90%5511.49%

*Flat/Rolling hills Interstate with 75mph speed limit?*

701217.91%653450.75%601725.37%5545.97%


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## NDKoze

I have seen some comments on speed in other topics, but no topic specific to address the question, so I thought I would start one.

I think it is safe to say that most people would not tow at the max posted speed limit.

I live in a pretty flat area (ND) without mountains, but with some rolling hills. Our Interstate speed limits are 75mph and non-Interstate highways are either 65mph or 55mph. That being said, ever since we hit $4.00 gas a couple of years ago, I started driving max 70mph with or without my 2,500lb pop-up camper and have never felt the need to go back to driving 75 now that gas is back down to $3.00.

I am contemplating the purchase of a 250RS and will be towing with a 2009 Chev Avalanche (7,800lb Max Tow with AutoRide Airbag Suspension). My guess would be that the max I would want to tow would be 65mph. I think I have seen mention that most trailer tires are only rated for 65mph anyhow. I towed my pop-up camper at 70 without knowing it was back there, but know that will not be the case with the 250RS.

There are probably a lot more factors that go into this than I am listing here, but I just thought it would be good/interesting to see what the averages are from more experienced towers.

Thank you in advance for your input.


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## Joe/GA

I tow between 60 and 65. Trailer tires are only rated for 65 MPH and I really don't want them to come apart while I'm driving. Allow yourself enough time and get there safely!


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## W4DRR

Also remember, the posted speed limit may not apply to towing. Most states have a lower limit for towing, some as low as 55MPH.
And as previously mentioned by Joe, ST type tires are only rated for 65MPH.

Bob


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## SLO250RS

When towing 65 max.







When we venture down to S.E.Ohio we run into some small grades and it is what the traffic and road conditions allow.But when I am not towing all bets are off


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## CdnOutback

I only will go 95 - 100 Km per hour while towing. That would be a max of 60 mph.... Any faster than that and you can watch the fuel gauge move way to quick. When we came back from Mesa a couple weeks ago, while heading north from Council Bluffs, IA through SD and ND we only got 6 - 7 mpg. We had a head wind the whole way. 350.00 of diesel in two days. That really sucked! (no pun intended)


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## Traveling Tek

Didn't know that about trailer tires only be rated at 65. I drive the speed limit. So it's 70 I go 70. 75 and up though and the trailer gets a heck of sway going that is really had to control and not very safe at all. Done about 40k mile with the trailer since I bought it, and the cruise is almost always at 65-68.


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## Nathan

Yes, all ST tires are rated at 65mph. Prior to knowing this I would do 70 with my pop up. With a TT, you're talking a lot of weight, wind resistance, etc. I'll play it safe and take it easy. With the 5'er, we had LT tires on it, and one time, on a lonely stretch of highway with a 75mph speedlimit, I pulled at ~72mph for a couple hours. That tank of gas netted 6mpg compared to my typical 9mpg. Not worth it to get there 10 minutes early.


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## duggy

Our "interstate" speed limit is 100 kph (62 mph). With the trailer in tow, I stick pretty close to that. If the speed limit was 75, I think I would still hold it to 65, both for safety and gas mileage. My 6.0 liter has no trouble going faster, but it sure lets you know at the pump.


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## KTMRacer

Usually tow between 60 and 65, no hurry to get anywhere now that we are retired. Mileage drops like a rock much over 60.

Southern Utah has a stretch of interstate with an 80MPH speed limit for cars and trucks. Road is littered with rubber from blown out truck tires.


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## mmblantz

I see campers tuckin in behind fast moving strings all the time. No way am I doin that. 65 max. I TRY TO leave early enough to get there before dark safely. ---Mike


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## Braggus

Max 65 any faster I don't feel comfortable.


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## tomE

Depending on my mood, 65 in 5th at 1800 RPM or 60 in 4th at 2500 with cruise control set. TV seems a little happier at the 60/4th set up. Mileage doesn't seem to be much different either way 9-10 depending on head winds.
As mentioned above, for the few minutes saved on a typical trip, driver arrives happier going a little slower.


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## NDKoze

This is awesome information!

I am very satisfied to drive 60-65mph and that appears to be what the consensus is. As I have gotten older (still not that old at 39), I have become much more patient and realize that that extra 10-15 minutes do not make a big difference in the whole scheme of things.

I am guessing with the flat land around here, I should be able to go 65mph most of the time. But as many of you have mentioned, you drive what the conditions allow.


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## Traveling Tek

Hrmm... I currently get 6mpg with my drive style. I will cut it back a bit and see if it helps.


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## GO WEST

With my 03 F150 5.4L with 3.55 going to Flagstaff and back we drove as low as 55 mph at times. Usually closer to 60. A few times up to 65. We saw 5'ers going by at 70 seemed like, and that made me feel a little slow and stupid, but I averaged around 8 mpg and I felt much safer at slower speeds. With gas prices what they are and greater danger/risk going faster, why do it? What's the rush any way? Camping should be leisurely, it's more fun that way!

I have not towed with my Suburban yet, but we plan on a big trip in June. With the 454/3.73 we could probably go faster than the F150 easily, but I still plan to shoot for 60 mph.

Be careful out there.


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## tomE

Traveling Tek, I'm a thinking you must be in a pretty big hurry.
I'm not an engineer but know we're all pushing a LOT of air out of the way, regardless of the length of our rigs. Drag is a function of velocity, as in the square of the velocity, not additive. e.g. 2x faster + 4X more work to get 'er done as in 2 x 2 + 4. Or something like that. (2 + 2 = 4, too. Maybe a bad example. Where is an engineer when you need one?) Anyhow, I saw this in my earlier 4 Runner. 60 MPH cruising 22 mpg. 70 MPH 19 mpg. 75 MPH 15 mpg (not towing). If time is money, go for it. Getting to the coast, I've made my decision. Only issue someone else can comment is "Is it better to be cruising 65 in 5th at 1800 RPM or 60 in 4th at 2500 - transmission-wise?" MPG doesn't seem to care.


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## Carey

I done some testing with my hitch in the 95-100mph range. No bs. Its all my hemi would do. Made it work way hard. Done about 15 miles like that. Had the cruise set on 80mph for an hour. Sucked down a whole tank of gas.. lol

When I towed for a living I kept things around 63mph.


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## dirtengineer

tomE said:


> Traveling Tek, I'm a thinking you must be in a pretty big hurry.
> I'm not an engineer but know we're all pushing a LOT of air out of the way, regardless of the length of our rigs. Drag is a function of velocity, as in the square of the velocity, not additive. e.g. 2x faster + 4X more work to get 'er done as in 2 x 2 + 4. Or something like that. (2 + 2 = 4, too. Maybe a bad example. Where is an engineer when you need one?) Anyhow, I saw this in my earlier 4 Runner. 60 MPH cruising 22 mpg. 70 MPH 19 mpg. 75 MPH 15 mpg (not towing). If time is money, go for it. Getting to the coast, I've made my decision. Only issue someone else can comment is "Is it better to be cruising 65 in 5th at 1800 RPM or 60 in 4th at 2500 - transmission-wise?" MPG doesn't seem to care.


Did someone ask for an engineer?









I am probably the wrong kind of engineer for this discussion, but I can confirm that 2 squared is 4 and 2 + 2 is 4. If anyone is really curious, I could probably go look it up in my old fluid dynamics textbook. The bottom line is faster = poor gas mileage.

I don't exceed 65, but I do try to drive as quick as I safely can as a courtesy to other drivers. Most roads in Alaska are two lanes with large stretches without pull outs or passing lanes.


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## clarkely

I travel 70 - 75

Generally set the cruise around 72 if open highway - if traffic i drive at speed of traffic..........

On last three GM tow vehicles i have found either 60 or 72 to be a sweet spot for the 3:73 rear......... I have gone faster and slower.........just sayin'

I expect someone to tell me to slow down and my tires aren't rated - so you wont offend me if you do it in a respectful manor.

Tires are rated for 65 - when they are rated for something they are also tested to exceed ratings - all ratings are tested to with stand a percentage above their ratings.

This current trailer has probably 12-13000 miles on it.


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## Nathan

dirtengineer said:


> Traveling Tek, I'm a thinking you must be in a pretty big hurry.
> I'm not an engineer but know we're all pushing a LOT of air out of the way, regardless of the length of our rigs. Drag is a function of velocity, as in the square of the velocity, not additive. e.g. 2x faster + 4X more work to get 'er done as in 2 x 2 + 4. Or something like that. (2 + 2 = 4, too. Maybe a bad example. Where is an engineer when you need one?) Anyhow, I saw this in my earlier 4 Runner. 60 MPH cruising 22 mpg. 70 MPH 19 mpg. 75 MPH 15 mpg (not towing). If time is money, go for it. Getting to the coast, I've made my decision. Only issue someone else can comment is "Is it better to be cruising 65 in 5th at 1800 RPM or 60 in 4th at 2500 - transmission-wise?" MPG doesn't seem to care.


Did someone ask for an engineer?









I am probably the wrong kind of engineer for this discussion, but I can confirm that 2 squared is 4 and 2 + 2 is 4. If anyone is really curious, I could probably go look it up in my old fluid dynamics textbook. The bottom line is faster = poor gas mileage.

I don't exceed 65, but I do try to drive as quick as I safely can as a courtesy to other drivers. Most roads in Alaska are two lanes with large stretches without pull outs or passing lanes.
[/quote]
Yes, drag increases with the square of the speed. That's just your money though.....









Please drive safely everyone!!!


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## Traveling Tek

All my fuel is a write off and paid for by someone else. I find that 70mph keeps me from getting passed by rigs which adds sway and feels way more dangerous to me then driving 5mph faster. 

Just feels safer to pass then be passed. When a rig comes along at 70mph I feel it "hit" my tail and shove me, then all the way up my rig to front where I go the other way. I hate that hold on feeling.


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## Joonbee

I typically tow around 68mph and empty (no trailer) is around 72mph. Just made a trip out to Mo and back, just over 900 miles one way and got 19.5mpg.

Jim


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## TwoElkhounds

On our trips out West I drive 70-75 across the midwest states. Maybe I shouldn't, but states like Kansas and South Dakota are really BIG and FLAT!!! It is just too easy. Sway is not a big problem for me as I have a very long truck and a relatively short trailer.

Gas mileage certainly gets hit. Trip last year to the Grand Canyon we got around 10 MPG. If I nurse it and keep the speed under 60 MPH I can get up to 15 MPG on a flat with a good tail wind. Guess this proves that time is indeed money.

DAN


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## clarkely

TwoElkhounds said:


> Guess this proves that time is indeed money.
> 
> DAN


So True!!

I came home from Marathon, NY yesterday with a couple other vehicles in our group - Not towing - skiing weekend, and i get it at 70 for 150 miles and got 20.3 on the computer.......then stomped on it for last 30 miles........


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## TexanThompsons

clarkely said:


> I travel 70 - 75
> 
> Generally set the cruise around 72 if open highway - if traffic i drive at speed of traffic..........
> 
> On last three GM tow vehicles i have found either 60 or 72 to be a sweet spot for the 3:73 rear......... I have gone faster and slower.........just sayin'
> 
> I expect someone to tell me to slow down and my tires aren't rated - so you wont offend me if you do it in a respectful manor.
> 
> Tires are rated for 65 - when they are rated for something they are also tested to exceed ratings - all ratings are tested to with stand a percentage above their ratings.
> 
> This current trailer has probably 12-13000 miles on it.


Shame on you. You drive too fast. You put us all in danger.

There, someone said it!


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## Camping Fan

I generally tow at 65-67 mph, will get up to 70 mph briefly if needed to pass. My Silverado could handle towing at 70+ mph easily, but the concern is not how fast I can go, but how fast I can safely stop in an emergency.


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## tomE

Absolutely, there is always the "whoa" factor at whatever speed we're going.
Drive to the conditions, don't be a pest, be comfortable doing it. If you're in someone's way, get out of it at a pull out, or get going. It used to be called lane courtesy. A lost art of driving these days. (oops, is that political?)
It sounds like most have the grunt to do whatever speed is appropriate, or necessary, to stay out of other's way, and be safe.
If I can get a fluid engineer on the phone, I post the speed/drag answer to my problematic example above.


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## clarkely

tomE said:


> Drive to the conditions, don't be a pest, be comfortable doing it. If you're in someone's way, get out of it at a pull out, or get going. It used to be called lane courtesy. A lost art of driving these days.


X2

It is a lost art to be a courteous driver!!


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## TexanThompsons

clarkely said:


> Drive to the conditions, don't be a pest, be comfortable doing it. If you're in someone's way, get out of it at a pull out, or get going. It used to be called lane courtesy. A lost art of driving these days.


X2

It is a lost art to be a courteous driver!!
[/quote]

X3

On our way back from Fort Wilderness on I-10 this past weekend there were several RVers stuck in the left lane. I could just see the steam coming off the heads of those passing them on the right.

By the way, we maintain about 63-65 to keep the miles per gallon in check. If you're in a hurry when you're headed campin' something is wrong with you! haha!


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## dirtengineer

tomE said:


> Absolutely, there is always the "whoa" factor at whatever speed we're going.
> Drive to the conditions, don't be a pest, be comfortable doing it. If you're in someone's way, get out of it at a pull out, or get going. It used to be called lane courtesy. A lost art of driving these days. (oops, is that political?)
> It sounds like most have the grunt to do whatever speed is appropriate, or necessary, to stay out of other's way, and be safe.
> If I can get a fluid engineer on the phone, I post the speed/drag answer to my problematic example above.


OK, so I broke out my Engineering Fluid Mechanics textbook by Roberson and Crowe. The drag force is equal to the drag coefficient X projected area X fluid density X 1/2 the velocity squared.

The drag coefficient is generally dictates by the shape of the object. My book lists a Volkswagen Bug at 0.46 and a Ford Taurus as 0.32. Too bad they don't list a Dodge pickup with a pipe rack or Outback 21RS! This is probably complicated by the fact that a trailer is larger and behind the tow vehicle causing all sorts of turbulent flow. A cube is has a coefficient of 1.1 - my guess is it couldn't be any worse than a cube.

Projected area is the frontal area of the object. Probably a pretty complex for the same reasons as above.

Fluid density is air and is subject to change based on atmospheric pressure, temperature, etc. 0.00237 slugs/cubic foot at 60 degrees and one atmosphere of pressure.

Velocity is the fluid velocity with respect to the object. So if you are traveling at 50 feet per second into a 20 ft/s headwind, this number would be 70 ft/s.

Like I said, this is outside my expertise. Hopefully there is a mechanical engineer on the forum that can check my assertions.


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## TexanThompsons

dirtengineer said:


> Absolutely, there is always the "whoa" factor at whatever speed we're going.
> Drive to the conditions, don't be a pest, be comfortable doing it. If you're in someone's way, get out of it at a pull out, or get going. It used to be called lane courtesy. A lost art of driving these days. (oops, is that political?)
> It sounds like most have the grunt to do whatever speed is appropriate, or necessary, to stay out of other's way, and be safe.
> If I can get a fluid engineer on the phone, I post the speed/drag answer to my problematic example above.


OK, so I broke out my Engineering Fluid Mechanics textbook by Roberson and Crowe. The drag force is equal to the drag coefficient X projected area X fluid density X 1/2 the velocity squared.

The drag coefficient is generally dictates by the shape of the object. My book lists a Volkswagen Bug at 0.46 and a Ford Taurus as 0.32. Too bad they don't list a Dodge pickup with a pipe rack or Outback 21RS! This is probably complicated by the fact that a trailer is larger and behind the tow vehicle causing all sorts of turbulent flow. A cube is has a coefficient of 1.1 - my guess is it couldn't be any worse than a cube.

Projected area is the frontal area of the object. Probably a pretty complex for the same reasons as above.

Fluid density is air and is subject to change based on atmospheric pressure, temperature, etc. 0.00237 slugs/cubic foot at 60 degrees and one atmosphere of pressure.

Velocity is the fluid velocity with respect to the object. So if you are traveling at 50 feet per second into a 20 ft/s headwind, this number would be 70 ft/s.

Like I said, this is outside my expertise. Hopefully there is a mechanical engineer on the forum that can check my assertions.
[/quote]







What he said.


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## Nathan

Don't forget the rolling resistance of the tires, axle bearing friction, driveline losses, etc.


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## rmeyer

Not considering weather and road factors:

I tow with my Expedition at about 65 on a good road. This feels comfortable for the engine as well as being able to control the trailer with this vehicle.

Now, when I borrow my Dad's 3/4 ton long wheel base Chevrolet Pickup with the diesel engine to tow my Outback, 75 on a good road feels good for the engine and the vehicle's ability to control the trailer. There is a monstrous difference the wheelbase and weight of the tow vehicle make in your abiltiy to control the weight behind you and should be taken into consideration.


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## vdub

Lonely desert road -- 65. Any congestion -- 60. Except in California where it's 55 if you are towing anything. Actually had a tire come apart a couple years ago. I'm glad I was only going 60.


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