Is 50 mpg at 65mph normal?

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One thing I read about but don't have the citation is tire resonance leading to higher drag. At higher speeds, a tire can setup a resonance that increases the rolling drag and tire heat. This is a complex phenomena but making the tires 'stiffer' with higher pressure should reduce this effect.

Bob Wilson

 

I always buy Costco gas and can get 65 mpg in town and 52 hwy. I don't have much of a lead foot I like to ease onto the freeway.

 

I have logged around 2,500 miles on a road trip from Delaware to Arizona, generally driving at 70 mph with a passenger and our stuff. 46 mpg.

 

You might consider adding to our knowledge using one of your trip meters:

• Wait 20 minutes into a first drive, 5 minutes on subsequent drives - to warm-up the car.
• Set your cruise control speed, dynamic or ordinary.
• Reset the trip meter and note the location (longitude/latitude is perfect) but City/State is good enough
• When ready to pull off, note or photo the trip meter and note the end location
• Record head-wind, tail-wind, and approximate strength and temperature but we can look up the weather records closest to your route

We can use the one-way, benchmarks to compare against the mph vs MPG chart. Not perfect, good enough to help everyone understand what the car does. This approach removes the warm-up penalty and helps account for weather, temperature, and altitude changes.

Bob Wilson

 

those charts are great, thanks bob. any chance of a simple mpg vs tire psi chart for the great unwashed?

 

I wish there were but it is not that simple because we still have to deal with all of the other variable: fuel, warm-up, temperature, e.t.c. But there may be a way to indicate a percentage improvement. Let me think about it for a bit.

Bob Wilson

 

1,800 mile drive from Austin to NYC. 54.3 mpg freeway at 70-80.

Posted via the PriusChat mobile app.

 

Ambient temperature plays a huge factor but basically anything above 55mph is wasting gas. Airpressure on the front of the car builds drastically above that speed. That's why many states had a max speed limit of 55mph for a long time.

Posted via the PriusChat mobile app.

 

I also wonder after the ice fully breaks in and looses up a bit, if then mpgs get better

Posted via the PriusChat mobile app.

 

seems like a dyno in controlled conditions would be the best way?

 

Mr. Google suggested: On-Road Fuel Consumption Testing to Determine the Sensitivity Coefficient Relating Changes in Fuel Consumption to Changes in Tire Rolling Resistance Calvin. - ppt download

Not quite what I was looking for but good enough.

Bob Wilson

 

on the pip, it gives you hv/ev miles on the trip meters. makes for an easy calc at the pump. is there any way to do it on prime?

 

Looking for something else: Bridgestone: Taller, Skinnier Tyres For Better Fuel Economy - Carlist.my





Bob Wilson

 

On the Drive Monitor screen, it will show you the EV Driving Ratio based on the current trip monitor you have selected (ODO, Trip A, Trip B or since Last Start). By multiplying this percent by the miles logged in the trip monitor, that'll give you the miles driven in EV mode and the difference is the miles driven in HV mode.

For example, the attached pic shows Trip A (since my last visit fill-up at the gas station, which was on Feb 4th). I've driven a total of 1,017 miles, with a 76% EV driving ratio, meaning I've driven about 771 miles in EV, and 243 in HV. I didn't take a pic, but the distance to empty is around 220 miles. And I have about a half tank left, so it's generally accurate.

 

Has anyone ever taken a look at the "Eco-Diary"? Last one under drive information.

 

Also, why do people assume the gas pump is ground-truth? It's not. The pump can be off and you are dividing by miles accumulated on the odometer, which can also be off.

 

I do because the laws of the land come down hard on both those, if they're off.