How much does a 25 mph headwind matter?

[Hermann]

To Jefferson City from Kansas City with a 25 mph tailwind 38°

From Jefferson City to Kansas City with a 25 mph straight on headwind. 35°

 

[tbm5690]

It makes a dramatic difference...that's a 50mph wind differential, so at least a 10 mpg hit on the headwind leg compared to the tailwind leg assuming you are going 70mph+. Be thankful you didn't get the headwind both ways!

 

[mr_boring]

I dunno about 10mpg, but agree that it will be considerable.

 

[wander2039]

Since I'm riding the bike today in those winds... 5mph faster coming to work and alot easier. Going home their will be more curse words and more food on the plate LOL.

 

[ATex7239]

Our minivan might as well be a wind sail at that point.

 

[supton]

No idea. But when I ride my bicycle I sure can tell the difference between a tailwind and a headwind!

Wind drag does go up proportional to the speed squared. There's that. I'd look at it like driving 60mph into a 25mph headwind as being similar to driving at 85mph. Only engine speed is lower and the transmission might downshift, so as to get a similar engine speed as driving at 85mph.

 

[Hermann]

I dunno about 10mpg, but agree that it will be considerable.

It was 7.5 mpg. My average speed was 70 indicated. Really 68 mph

 

[Cujet]

No idea. But when I ride my bicycle I sure can tell the difference between a tailwind and a headwind!

I used to bicycle to work, for training between races. 22 miles in, 27 miles home. Took just over an hour to get to work and about 1.5 hours getting home.

On Christmas day back in 1996, there was a 25MPH headwind. It took me many hours to get home. I had to stop at a 7-11 twice for meals and fluids.

So, you are absolutely correct, a headwind is a brutal thing.

Consider this: An airplane going 100 miles at 100MPH will take an hour. But if you have a 90MPH headwind, it will take 10 hours to get there and just over a half hour to get back. The point being, headwinds and tailwinds don't "even out".

 

[andrew_j]

Our 2018 Tiguan drops from 29 MPG to about 23 MPG if we put roof rack on with large Thule box with maybe 75 lbs in it and a mountain bike on top of car. The air resistance makes a pretty large impact on fuel economy.

 

[supton]

I used to bicycle to work, for training between races. 22 miles in, 27 miles home. Took just over an hour to get to work and about 1.5 hours getting home.

On Christmas day back in 1996, there was a 25MPH headwind. It took me many hours to get home. I had to stop at a 7-11 twice for meals and fluids.

I could believe it. Below 10mph or so, wind drag goes way down, but, its wicked demoralizing to go that slow (I know, I often crawl up hills at like 6mph, some times I just give up and walk). Into a 25mph headwind I could see one barely managing 5mph as it'd be like trying to pedal at 30mph. Which is something I could only wish of doing on flat ground!

 

[mr_boring]

It was 7.5 mpg. My average speed was 70 indicated. Really 68 mph

My gut told me about 6-7, not bad for a fat old gut!

 

[mk378]

Yes it's really bad since like the airplane you're using fuel at gallons per hour like you're going 95 mph, but the car is only covering ground at 70 mph. So since you're on the road for a longer time the final mpg is worse than completing the trip at 95 in still air.

 

[Hermann]

It makes a dramatic difference...that's a 50mph wind differential, so at least a 10 mpg hit on the headwind leg compared to the tailwind leg assuming you are going 70mph+. Be thankful you didn't get the headwind both ways!

That has happened before

 

[Leo99]

My gut told me about 6-7, not bad for a fat old gut!

Hey, don't be so hard on yourself. It's not that old.

 

[supton]

That has happened before

I swear that happens every time when I ride my bicycle. I can go out for a loop and it sure can feel like a headwind no matter where I am.

 

[Pew]

The differences between the tailwind and headwind look similar to my experiences in the focus. Driving east/West across the Midwest I will often come across 25+mph crosswinds which would drop my 39mpg @ 75mph down to 33-36 mpg.

 

[pghvolvo]

It also matters what the Cd (Coefficient of Drag) of you vehicle is. The higher the number the bigger impact a head wind will have on your fuel economy. A vehicle with a .Cd of .28 isn't going to be impacted as much as a vehicle with a .Cd of .40. People have no idea just how much exterior accessories like roof boxes, ski, kayak and bicycle racks affect their fuel economy. If you're not using these units, take them off the top of your vehicle.

 

[Hermann]

The differences between the tailwind and headwind look similar to my experiences in the focus. Driving east/West across the Midwest I will often come across 25+mph crosswinds which would drop my 39mpg @ 75mph down to 33-36 mpg.

Sidewinds of more than 10-15 mph are some times worse mpg wise. It really screws up the airflow under the vehicle. . At least a direct headwind doesn't blow you all around in your lane.

 

[wwillson]

It makes a big difference.

Duramax 3.0L oil consumption while driving with low RPMs and high power output

A friend of mine called me yesterday asking about poor fuel economy in his 3.0L Duramax. His drive was from Kentucky to Denver in 30+ MPH headwinds. He normally gets 29.5 MPG, but one this trip he only got 20.5. He wanted to know if I thought something was wrong with the engine, because it...

bobistheoilguy.com

 

[CR94]

Wind drag does go up proportional to the speed squared. There's that. I'd look at it like driving 60mph into a 25mph headwind as being similar to driving at 85mph. Only engine speed is lower and the transmission might downshift, so as to get a similar engine speed as driving at 85mph.

Driving 60 mph into a 25mph headwind hypothetically might result in the same drag force as driving at 85 mph with no wind, but would require only 60/85 as much power to overcome that drag. Power=speed times force. There'd likely be no need for the transmission to downshift (vs. the 85-mph, no-wind condition), so the engine would run slower while producing about the same torque.