Topic: Why Bikes Really Get Lousy Fuel Mileage - All Things Considered

[BobbyR]

Yes they do say the same thing but I am certain they did not read the article carefully if at all. The motorccyle gets very poor mileage for it's size and weight. It may get twice the mileage of a Hummer, but for it's weight it should get several times the mileage.

The Motorcycle is not bad, it just has dymanic forces working against it. This is about science, not about the merits of the Motorcycle as a mode of transportion.   

[mystic_1]

Wonder what sort of mileage they'd get if they were on a frictionless conveyor belt....



mystic_1

[Jerry Rxman Griffin aka MuthaF'er]

Mileage example (warning-this may hurt your eyes): (without reading the article)

My HARLEY Fat Boys

2001 Stock (a good pair of tennis shoes would out run it)
Best: 65mpg.
Worst: I really didn't have it long enough to judge (head-on collision)

2003 Engine modded (refer to the tennis shoe comment above) 
Best:60mpg only once (not sure what got into it then) perhaps 70mph average cool damp day some wet roads
Worst: 29mpg
Average: naked bike perhaps 44-45mpg if I can contain myself @ 70-75mph

Some reasons for poor mileage that are legit:
BIG ass windshield
Large heavy pack on sissy bar
BIG full heavy soft bags on both sides
Cooler full of beer (12 pack and ice)
85+mph
Desert temps up to ~120 degrees

The 2 biggest contributors are the speed and the BIG ass windshield. The windshield legitimally accounts for 5mpg so it only stays on for my long road trips.

1975 CB750F: naked bike avg 45mpg @ 75mph ; 40mpg @ 80mph

[HavocTurbo]

I don't disagree with you on the motorcycle being seriously inefficient.

I just found it funny that's all.

Yes they do say the same thing but I am certain they did not read the article carefully if at all. The motorccyle gets very poor mileage for it's size and weight. It may get twice the mileage of a Hummer, but for it's weight it should get several times the mileage.

The Motorcycle is not bad, it just has dymanic forces working against it. This is about science, not about the merits of the Motorcycle as a mode of transportion.   

[Joel]

Yes they do say the same thing but I am certain they did not read the article carefully if at all. The motorccyle gets very poor mileage for it's size and weight. It may get twice the mileage of a Hummer, but for it's weight it should get several times the mileage.

The Motorcycle is not bad, it just has dymanic forces working against it. This is about science, not about the merits of the Motorcycle as a mode of transportion.   

I read the article and I understand the point.  However, most people don't view efficiency as defined that way.  The motorcycle is a trade off.  It has more aerodynamic drag and lower passenger capacity, but it gets more miles per gallon than most vehicles.

[Gordon]

Yes they do say the same thing but I am certain they did not read the article carefully if at all. The motorccyle gets very poor mileage for it's size and weight. It may get twice the mileage of a Hummer, but for it's weight it should get several times the mileage.

The Motorcycle is not bad, it just has dymanic forces working against it. This is about science, not about the merits of the Motorcycle as a mode of transportion.   

Yes, I read the entire article and my reading comprehension is just fine.

I understand perfectly that for the total amount of weight that a motorcycle is moving, it's less efficient than a car that's moving much more weight.  But, like I already said, since the whole point of driving the car or motorcycle is to get yourself (not the total weight of the vehicle) from point A to point B, anything that uses less fuel to do this job is inherently more efficient. 

If I ride my motorcycle 100 miles and use two gallons of gas, and then drive my car the same 100 miles and use 4 gallons of gas, which method of transporting myself was more efficient?

Now, if you want to move multiple people it's a different story.  Put four people on four separate motorcycles and you're going to burn more gas to move them the same distance as one car would use to move the same four people inside it.     

[CBGBs]

I posed the question once about lowered motorcycles and why is it so popular. Some said there was an aerodynamic advantage and there were debates on that. This is an interesting extension of that thread long ago. I didn't see the point unless you were short or maybe drag racing but other than that its kind of a stupid trend and probably has some unwanted consequences to the balance  and handling of the bike.

[Joel]

I posed the question once about lowered motorcycles and why is it so popular. Some said there was an aerodynamic advantage and there were debates on that. This is an interesting extension of that thread long ago. I didn't see the point unless you were short or maybe drag racing but other than that its kind of a stupid trend and probably has some unwanted consequences to the balance  and handling of the bike.

Lowering it should reduce the frontal area and thus the drag, but it's probably such a small reduction that the effect is negligible.  I don't know what effects it has on handling but it might be slightly easier to balance when stopped.

[BobbyR]

Yes they do say the same thing but I am certain they did not read the article carefully if at all. The motorccyle gets very poor mileage for it's size and weight. It may get twice the mileage of a Hummer, but for it's weight it should get several times the mileage.

The Motorcycle is not bad, it just has dymanic forces working against it. This is about science, not about the merits of the Motorcycle as a mode of transportion.   

Now, if you want to move multiple people it's a different story.  Put four people on four separate motorcycles and you're going to burn more gas to move them the same distance as one car would use to move the same four people inside it.     

Yes exactly the point. I was reading an article about Honda trying to increase the fuel mileage of the bikes. They focused on the motors, using multiple plugs per cylinder, processor controlled direct fuel injection and combustion chamber design.  I guess they figured the aerodynamics was what it was going to be. Ride on and be happy.
This one guy about 10 miles away from me smokes his own Bacon and if it is not too cold I ride my bike. People ask me why I ride the bike to get Bacon. I simply tell them it makes no sense to take a 5000 lb car to carry 5 lbs of bacon.
So, I agree with you all on that point, I just found the Science interesting.

[SanDogDewey]

my old 750 get about 48mpg
thats plenty good for me
i like the wind in my chest
and finally, can you really compare riding a bike to driving a car?
i think not

My '77 CB750 with 2,200 miles gets 31 @ 70 mph and drops to around 20 @ 90, but I agree...who cares.

[ColinMc]

I posed the question once about lowered motorcycles and why is it so popular. Some said there was an aerodynamic advantage and there were debates on that. This is an interesting extension of that thread long ago. I didn't see the point unless you were short or maybe drag racing but other than that its kind of a stupid trend and probably has some unwanted consequences to the balance  and handling of the bike.

Lowering it should reduce the frontal area and thus the drag, but it's probably such a small reduction that the effect is negligible.  I don't know what effects it has on handling but it might be slightly easier to balance when stopped.

I have an S10 I lowered 4 inches all the way around, I now average 28 mpg on the highway on my nearly weekly trips to CT with it instead of 21 at best before...

[Rocking-M]

my 77 F750 got 48 on average, that's riding hard in the mountains.
The Duck ST with the 916 4 valve gets 50 and some change.

I define efficiency as what cost me the most at the pump. The bikes win.

[BobbyR]

my 77 F750 got 48 on average, that's riding hard in the mountains.
The Duck ST with the 916 4 valve gets 50 and some change.

I define efficiency as what cost me the most at the pump. The bikes win.

Granted. To me it was scientifically interesting. I often wondered why the mileage on bikes was not orders of magnitude higher. I never expected so much wind drag.

[Rocking-M]

Bobby, I actually knew that one, surprises never cease eh? 
The reason I knew was top end speeds for the sportbikes versus the sportcars.
But still, given the looks of the frontal area it's still sort of surprising that drag
coefficients are so much more.

[BobbyR]

Oh well, we just live with it and ride.