How fast do you drive?

["EZ"]

I usually set the cruise on 68 on the Interstate. My bus seems to like it there. I speed up to pass of course. ?

 

[tileman]

About 65, unless traveling through a city. Then I travel the safest speed for traffic flow.

 

[B&T RVers]

I tried to stay between 60-62. Only had the rig a month so may be more comfortable getting up to 65. At the end of the day we didn’t get the coach to go fast. Time to slow things down!

 

[GlampDaddy]

I previously posted that I drive in the 62 to 65 range. But...we just returned from a trip to Quartzsite AZ (from Austin TX), traveling with two Mountain Aires, a London Aire and a King Aire. They set the pace at 70 and I kept up, for the most part. On the return trip, with my speedy friends gone in another direction, I found anything below 70 felt like a snail's pace.

 

[Joe Hogan]

We have found that the CanyonStar becomes decidedly uncomfortable to drive at 70 or above. The aerodynamics of the Brick starts to unload the frontend causing a vague steering response and uncomfortable handing. I'll occasionally pass a slower vehicle at 70 mph, but each time I am reminded that the CanyonStar is not meant to maintain such speed comfortably. Luckily I am not in a hurry to get anywhere, and to me that is the point of my travels. This is besides the horrendous fuel economy at 70 mph.

 

[lemondrop9344]

Try to keep the RPM's as close as possible to around 1600 - 1650 based on recommendation from Gaffney Camp Freightliner class. (CAT C-7 350 HP). This equates to somewhere around 60 -65 MPH with my RV. On the interstates I generally find I am going slower than most of the traffic, so I keep to the right. On two lane roads, I try to stay as close as possible to the posted speed limit.
I try to enjoy the journey getting there as much as the destination. Topography & roads generally govern how many hours a day I drive.

 

[AbdRahim]

I try to maintain 65. On steep grades, I can sometimes barely maintain 55. Not worth the extra gas to go faster. Where the speed limit is 70 or above I try to stay at 65 to 70. Mileage seems to drop markedly over 60, so unless I am trying to make a deadline, I don't push it.

 

[Pablo]

In internal combustion engines there are three main curves: power, torque and...............something called Brake Specific Fuel Consumption (BSFC). This last curve is the one that you are referring to. The position of the "peak point" of this curve varies for each design and it has to do with the design of the engine, the design of the cams that open the valves, the overlap of the cams when both stay open, diameter of the piston in relation to the displacement, crankshaft dimension, RPM's, masses and inertia of the engine components, etc, etc, etc. This curve reflects the efficiency of the engine, not how efficient the engine is but where the maximum efficiency is located on the curve in relation to the RPM's. In other words, it shows how capable the engine is in generating HP @ a certain RPM with the best fuel consumption. Said it in a different way......the least fuel burned per HP produced or the best bang for you buck if you like. That is the reason why up to a certain RPM you will get the best results but crossing that point the engine will still deliver more HP (almost all the way up to the maximum RPM, but not at the maximum RPM) but the fuel economy drops. The internal combustion engine does not deliver the highest power at the maximum RPM, that happens before the engine reaches that point.
Ideally you would want that curve to be as flat as possible for the widest possible RPM range but Otto didn't make it that efficient. In fact the internal combustion engine is an extremely poor performer in terms of efficiency. You give it 100% of power (fuel) and it gives you back (at the flywheel) around 25% for gasoline engines. The rest is wasted in heat and friction. The Diesel engine is a little more efficient but not by much (around 35%).
I hope this explanation makes sense.

​

 

[Joe Hogan]

if you like the math regarding BSFC Brake Specific Fuel Consumption (BSFC) – x-engineer.org

 

[rjwilliams11741]

Speed depends on where I am. We own a 27 Coachman Leprechaun which handles nicely at 72 on an open, reasonably straight highway. Anything over that speed it starts feeling "goosey". When driving on I-80 across our home state of Nevada the speed limit is in places 80 I just stay in the slow lane and set the speed control to just under 72 and keep a watch our for big rigs passing. When pulling a TOAD or our 17 ft. boat we reduce the speed to at least whatever that particular states limit is for vehicles with a tow. On two lane twisty road I drive the speed that feels comfortable and safe and if I'm holding up traffic I use turnouts.