Is this true for only geared bicycles or fixed-gears too?
Let’s define “efficiency” first.
I love bicycles, but I think the sailboat has it beat.
It’s complicated to compare efficiency between vehicles with different energy sources.
But comapring multi-speed to single-speed bikes, the multi-speed bike would be more efficient, as it allows the legs to operate at a more comfortable and efficient speed. How much more efficient? That depends. If a bike has only one gear ratio, but the ratio is well matched to the route and rider’s ability, then its efficiency would be pretty close to a multi-speed.
Depends on how you define the energy consumption of a sailboat - is it the energy contained in the wind that is captured by the sail? Or is it zero, because the energy is free and/or not carried onboard? If the latter, a solar car would also have zero energy consumption.
I suspect that the bicycle is the most efficient transport for one person on paved and level roads. I wouldn’t want to use one to try to climb a mountain, however, and for bulk transport (e.g., of oil and coal), transportation by ship or barge on canals or oceans seems to be the most efficient for large amounts (i.e., thousands or millions of tons).
They say that small sprockets have bigger energy losses because they force the chain to make a tight bend. If that is true, then you can maximize efficiency by choosing the biggest sprocket at both front and rear on a multi-geared bicycle.
My gut feeling however is that a fixed-gear bicycle is more efficient despite the small rear sprocket. My guess is that the chain tensioner on multi-geared bicycles adds a lot of resistance.
Maybe true in theory, but don’t do this in practice. It puts a lateral tension on the chain that greatly increases the chances of breaking it.
Farting on roller-skates uses less energy. :eek: