12-07-2019, 09:00 AM
Other factors that affect gas mileage are cruising speed, and how much stuff you have on the bike.
Air resistance increases in proportion to the square of the velocity. This means that if you double your speed, you need four times as much energy to overcome air resistance. That doesn't mean if you double your speed you'll halve your gas mileage, because there are other factors involved such as friction of engine parts, bearings, tire rolling resistance, etc., and those things also increase with speed, but not to the same degree that air resistance does.
How much stuff you have and how much it is sticking out into the airflow makes a big difference to gas mileage too. Poor aerodynamics and and added weight are both going to reduce gas mileage.
If you're doing 50 mph on a flat road with a compact load and a tail wind, 60 mpg. If you're doing 75 mph with side cases, a passenger, and the kitchen sink loaded on top of the top box and a headwind up a long grade, 35 mpg if you're lucky.
Air resistance increases in proportion to the square of the velocity. This means that if you double your speed, you need four times as much energy to overcome air resistance. That doesn't mean if you double your speed you'll halve your gas mileage, because there are other factors involved such as friction of engine parts, bearings, tire rolling resistance, etc., and those things also increase with speed, but not to the same degree that air resistance does.
How much stuff you have and how much it is sticking out into the airflow makes a big difference to gas mileage too. Poor aerodynamics and and added weight are both going to reduce gas mileage.
If you're doing 50 mph on a flat road with a compact load and a tail wind, 60 mpg. If you're doing 75 mph with side cases, a passenger, and the kitchen sink loaded on top of the top box and a headwind up a long grade, 35 mpg if you're lucky.