Wind causes dramatic difference in mileage?
Road Master
Joined: May 2008
Posts: 1,136
Likes: 93
From: Andrews, NC
I don't worry too much about miles per gallon as much as how many miles
to a tankful of gas.
It has been my experience that the less I ride, the longer a tank of gas will last.
For instance, if I ride to a bar and sit there all day, my tank of gas will last longer!
to a tankful of gas.
It has been my experience that the less I ride, the longer a tank of gas will last.
For instance, if I ride to a bar and sit there all day, my tank of gas will last longer!
That's a big difference. But if you rode one way with a headwind and the other way with a tailwind I can understand the change in MPG. The difference between 65 MPH and 80 MPH is more than you might think as well.
Ultimate HDF Member
Joined: Dec 2006
Posts: 5,878
Likes: 17
From: The Desert SouthWest
I had a major headwind for a few hundred miles coming south from Salt Lake City once on an Electra Glide and got 25 mpg at fill-up. So yes it can make a significant difference!
Club Member
Joined: Jun 2007
Posts: 45,429
Likes: 2,898
From: Bedford UK
An elderly friend of mine and long time rider (no longer with us) had a favourite saying that there is nothing a bike likes more than a following wind! If you had been riding in the other direction your bike would have sailed along on the aroma from your tank. So you haven't had an unusual experience.
Current bikes have very high gearing, so with a headwind you were probably doing the wise thing maintaining a higher speed, to get the motor up onto a decent part of the torque curve. Much slower and your bike may have struggled, even got poorer mileage.
Current bikes have very high gearing, so with a headwind you were probably doing the wise thing maintaining a higher speed, to get the motor up onto a decent part of the torque curve. Much slower and your bike may have struggled, even got poorer mileage.
Wind plays a big role in respect to mileage. If your riding into a 30 mph headwind and you are doing 60mph that's equal to 90mph worth of wind resistance.
My bike got over 60mpg when I rode with a 50mph tail wind. I couldn't believe it.
On the way back I was lucky to get 35mpg,and had to stay in 5th because I almost had to wind it out when trying to maintain 70 in 6th.
I manage to average 42-45 mpg unless the wind is up.
My bike got over 60mpg when I rode with a 50mph tail wind. I couldn't believe it.
On the way back I was lucky to get 35mpg,and had to stay in 5th because I almost had to wind it out when trying to maintain 70 in 6th.
I manage to average 42-45 mpg unless the wind is up.
Makes sense I'd say!
__________________
General Inquiries:
Info@LongRideShields.com
Sales and Marketing:
Sales@LongRideShields.com
Phone:
775.331.3789
General Inquiries:
Info@LongRideShields.com
Sales and Marketing:
Sales@LongRideShields.com
Phone:
775.331.3789
Grand HDF Member
Joined: Jan 2012
Posts: 4,458
Likes: 2,877
From: Oklahoma
Air resistance changes by the square of the change in velocity. On a day with no wind, you get a certain amount of resistance at 50 mph. On another you ride at 70 mph into a 30 mph headwind generating a 100 mph speed through the air. The wind drag is now 4 times what it was at 50 mph with no wind. That extra resistance costs lots of gas.
I believe power enrichment is programmed into the fuel map, I know it is set into carburetors. When you ask for more than 75% of the available power, the fuel mixture is enriched for more power and to help cooling. Available power varies with RPM. To just pick some numbers, our engines may only develop 10 hp when at full throttle and held at 1000 rpm, perhaps 60 hp available at 3500 rpm at full throttle and full rated power at the RPM where the horsepower peaks. If you are cruising at 3500 rpm using 25 horsepower you are using a little less than half of the available power. Now, at the same speed/rpm, you climb a hill or get a strong headwind you may need 50 hp to maintain speed and RPM. 75% of 60 hp is 45 hp and you are asking for 50 hp with your throttle position. Fuel flow will increase proportionally until 45 hp and increase at a higher rate above 45 hp for power enrichment. Running at high speed into a strong wind gives you exponentially higher wind resistance AND if the power to do that exceeds 75% of the available, fuel flow increases non-proportionally for the power requested above 75%. Fuel economy tumbles drastically. Under this condition, cruising in 5th might save fuel.
I didn't mean to "build the watch", but perhaps this will help to understand why speed is expensive.
I believe power enrichment is programmed into the fuel map, I know it is set into carburetors. When you ask for more than 75% of the available power, the fuel mixture is enriched for more power and to help cooling. Available power varies with RPM. To just pick some numbers, our engines may only develop 10 hp when at full throttle and held at 1000 rpm, perhaps 60 hp available at 3500 rpm at full throttle and full rated power at the RPM where the horsepower peaks. If you are cruising at 3500 rpm using 25 horsepower you are using a little less than half of the available power. Now, at the same speed/rpm, you climb a hill or get a strong headwind you may need 50 hp to maintain speed and RPM. 75% of 60 hp is 45 hp and you are asking for 50 hp with your throttle position. Fuel flow will increase proportionally until 45 hp and increase at a higher rate above 45 hp for power enrichment. Running at high speed into a strong wind gives you exponentially higher wind resistance AND if the power to do that exceeds 75% of the available, fuel flow increases non-proportionally for the power requested above 75%. Fuel economy tumbles drastically. Under this condition, cruising in 5th might save fuel.
I didn't mean to "build the watch", but perhaps this will help to understand why speed is expensive.
HD Forum Stories
The Best of Harley-Davidson for Lifelong Riders
7 Surprising Harley-Davidson Products that Are Not Motorcycles
Verdad Gallardo
8 Best Harley-Davidson Motorcycles Ever
Pouria Savadkouei
10 Worst Harley-Davidson Motorcycles Ever
Pouria Savadkouei
Killer Custom's Jail Break Is The Breakout That Refused to Blend In
Verdad Gallardo
Crazy Bunderbike Build Looks Amazing, But Is It Impossible to Ride?
Verdad Gallardo
Harley-Davidson Reveals Super Cool Cafe Racer Concept
Verdad Gallardo
Engraved Rebellion: Inside Bundnerbike's Glam Rock II
Verdad Gallardo
10 Motorcycles You Should Never Buy
Joe Kucinski
10 Things Harley-Davidson Needs to Fix in 2026
Verdad Gallardo
Thread Starter
|
Seasoned HDF Member
Joined: Sep 2009
Posts: 17,145
Likes: 6,168
From: SE Michigan
Air resistance changes by the square of the change in velocity. On a day with no wind, you get a certain amount of resistance at 50 mph. On another you ride at 70 mph into a 30 mph headwind generating a 100 mph speed through the air. The wind drag is now 4 times what it was at 50 mph with no wind. That extra resistance costs lots of gas.
I believe power enrichment is programmed into the fuel map, I know it is set into carburetors. When you ask for more than 75% of the available power, the fuel mixture is enriched for more power and to help cooling. Available power varies with RPM. To just pick some numbers, our engines may only develop 10 hp when at full throttle and held at 1000 rpm, perhaps 60 hp available at 3500 rpm at full throttle and full rated power at the RPM where the horsepower peaks. If you are cruising at 3500 rpm using 25 horsepower you are using a little less than half of the available power. Now, at the same speed/rpm, you climb a hill or get a strong headwind you may need 50 hp to maintain speed and RPM. 75% of 60 hp is 45 hp and you are asking for 50 hp with your throttle position. Fuel flow will increase proportionally until 45 hp and increase at a higher rate above 45 hp for power enrichment. Running at high speed into a strong wind gives you exponentially higher wind resistance AND if the power to do that exceeds 75% of the available, fuel flow increases non-proportionally for the power requested above 75%. Fuel economy tumbles drastically. Under this condition, cruising in 5th might save fuel.
I didn't mean to "build the watch", but perhaps this will help to understand why speed is expensive.
I believe power enrichment is programmed into the fuel map, I know it is set into carburetors. When you ask for more than 75% of the available power, the fuel mixture is enriched for more power and to help cooling. Available power varies with RPM. To just pick some numbers, our engines may only develop 10 hp when at full throttle and held at 1000 rpm, perhaps 60 hp available at 3500 rpm at full throttle and full rated power at the RPM where the horsepower peaks. If you are cruising at 3500 rpm using 25 horsepower you are using a little less than half of the available power. Now, at the same speed/rpm, you climb a hill or get a strong headwind you may need 50 hp to maintain speed and RPM. 75% of 60 hp is 45 hp and you are asking for 50 hp with your throttle position. Fuel flow will increase proportionally until 45 hp and increase at a higher rate above 45 hp for power enrichment. Running at high speed into a strong wind gives you exponentially higher wind resistance AND if the power to do that exceeds 75% of the available, fuel flow increases non-proportionally for the power requested above 75%. Fuel economy tumbles drastically. Under this condition, cruising in 5th might save fuel.
I didn't mean to "build the watch", but perhaps this will help to understand why speed is expensive.
Thread
Thread Starter
Forum
Replies
Last Post
travroc
General Harley Davidson Chat
26
Jul 2, 2008 07:33 AM