The most efficient motorised transport

[Caph]

Is the motorised bicycle the most efficient road legal mode of motorised transport available to mankind?

It surely must be close? Most of the energy expended goes towards propelling the rider rather than propelling itself which gives it a headstart over most other motorised vehicles I would think.

 

[Mussels]

It depends how you measure efficient and whether you class pedelecs as motorised transport.
It's efficient at getting me to work but then it's more pedal powered than motorised, if I tried using it to get my family on holiday then I would class it as very inefficent.

 

[Caph]

Yes, very good point. It's efficient up to a point but beyond that it is not viable, but still, is it not the most efficient at carrying its intended payload of one person?

It got me thinking when I was overtaken by one of those small buses up a hill today. It was carrying one person which I though was a waste. Then I thought, I wonder how many people it would take to push that bus up this hill. Then I thought, I wonder how many ebikes I personally could push up this hill. The relative efficiency staggered me. I wonder how much fossil fuel is currently being used to transport the transport carrying people rather than transporting the people themselves?

 

[Bandit]

Is the motorised bicycle the most efficient road legal mode of motorised transport available to mankind?

It surely must be close? Most of the energy expended goes towards propelling the rider rather than propelling itself which gives it a headstart over most other motorised vehicles I would think.

It ought to be close, because the un-motorised bike is widely said to be the most efficient, and that has a not terribly efficient engine. According to MacKay's chart, the closest thing to a push bike is a "cross country" type electric train when it is full. This has something to do with being long and thin (thus sharing the same air resistance with the maximum number of people) and not going too fast (which high speed electric trains do, if efficiency is your main concern).

 

[Ultra Motor]

I would say it has to be the cheapest and most efficient form of powered transport. The motors are typically 90% + efficient, agains a motorbike or car at circa 60%.

I am running calculations on running costs and emissions, will share once complete.

 

[onmebike]

I would say it has to be the cheapest and most efficient form of powered transport. The motors are typically 90% + efficient, agains a motorbike or car at circa 60%.

I am running calculations on running costs and emissions, will share once complete.

Don't forget to include replacement battery costs? Thats where a 50cc moped starts to appear more economical? The moped also benefits from better range, speed, two seats, better tyre mileage and zero effort.
A daily 10 mile commute 5 days a week will cost in fuel approx £3.00 on a moped. £468.00 every 3yrs. Thats approx the cost of a replacement ebike battery, which may not last 3yrs.

 

[flecc]

In energy only terms motorised bikes are the most efficient. This is simply because the base vehicle, an unpowered bike, is already the most efficient method of human powered propulsion, more efficient than the equipment we are born with. It follows that an added motor benefits from that innate efficiency.
.

 

[Ultra Motor]

Don't forget to include replacement battery costs? Thats where a 50cc moped starts to appear more economical? The moped also benefits from better range, speed, two seats, better tyre mileage and zero effort.
A daily 10 mile commute 5 days a week will cost in fuel approx £3.00 on a moped. £468.00 every 3yrs. Thats approx the cost of a replacement ebike battery, which may not last 3yrs.

How many miles are you guys getting out of a set of tyres? I am factoring this into my calculations!

 

[flecc]

How many miles are you guys getting out of a set of tyres? I am factoring this into my calculations!

Rough average 6000 miles for me, 7000 plus fronts, 5000 or so rear.
.

 

[lemmy]

It would be hard to beat the modern small diesel in terms of practical efficiency.

My Peugeot 207 carried 5 people and their luggage, 320 miles across France and back and returned an average of 62.3mpg. That's measured brim to brim, the computer shows 63.5mpg.

I find that remarkable and it's probably not the most economical car available even so. £30pa road VED too.

 

[Ultra Motor]

It would be hard to beat the modern small diesel in terms of practical efficiency.

My Peugeot 207 carried 5 people and their luggage, 320 miles across France and back and returned an average of 62.3mpg. That's measured brim to brim, the computer shows 63.5mpg.

I find that remarkable and it's probably not the most economical car available even so. £30pa road VED too.

Hi Lemmy, I suppose its what you class as efficiency. If we define efficiency as getting across town or commuting circa 20 miles then a pedelec will win hands down every time. However if efficiency takes into account time and carrying capacity etc over a distance then its hands down to a small diesel!

 

[Ultra Motor]

Rough average 6000 miles for me, 7000 plus fronts, 5000 or so rear.
.

Thanks Flecc

 

[Mussels]

How many miles are you guys getting out of a set of tyres? I am factoring this into my calculations!

If I include tyres that fail prematurely then the average is probably about 3000 miles.

 

[flecc]

If I include tyres that fail prematurely then the average is probably about 3000 miles.

Kenda brand?
.

 

[Mussels]

Kenda brand?
.

Kenda and Continental have both failed quickly, I didn't count all the Kenda failures as I knew some would fail quickly and I wouldn't have bought them myself.
The latest Kenda tyres on the 906 have done much better and covered a lot more miles than last years.

 

[flecc]

Kenda and Continental have both failed quickly, I didn't count all the Kenda failures as I knew some would fail quickly and I wouldn't have bought them myself.
The latest Kenda tyres on the 906 have done much better and covered a lot more miles than last years.

Yes, they seemd to have a bad patch in the middle years of the forum. My 1996 bike's Kendas lasted well and they seem ok again now.
.

 

[tangent]

I would say it has to be the cheapest and most efficient form of powered transport. The motors are typically 90% + efficient, agains a motorbike or car at circa 60%.

Electric motors are not 90% efficient. This is marketing white noise. Some may have a peak efficiency of over 90%, but the actual efficiency at any instant depends on the characteristics of the motor, the load (torque) on the motor and the spin speed. The same can be said for cars/motorbikes engines. Typically when pulling away motors/engines are at there least efficient (a stalled motor has zero efficiency). Efficency will then rise as the spin rate rises, reach a peak and then diminish again.

I have no numbers to back it up, but intuitively the bikes with crank based motors must be more efficient overall as the motors can operate close to there maximum efficiency for more of the time.

 

[tillson]

I have no numbers to back it up, but intuitively the bikes with crank based motors must be more efficient overall as the motors can operate close to there maximum efficiency for more of the time.

I agree with that. The motor on a hub type unit is effectively stuck in one gear all off the time, so it is only operating at its optimum efficiency at one road speed. Whereas a crank drive motor will be at its optimum efficiency at a range of different road speeds, the number of these efficient road speeds being a function of how many gears the bike has. Therefore, the crank drive must be more efficient overall.

 

[flecc]

I have no numbers to back it up, but intuitively the bikes with crank based motors must be more efficient overall as the motors can operate close to there maximum efficiency for more of the time.

Of course the Panasonic type unit operates with pulses of power on each pedal stroke so the power can peak on each pedal thrust, the amount of the peak depending on rider input to the torque sensor. Obviously the efficiency can vary considerable according to circumstances as shown by ranges varying by as much as 2 to 1 according to rider and technique on the control. Here's a power output graph of a Kalkhoff Agattu in motion, power averaging about 250 watts with some 400 watt pedal thrust peaks:

 

[tangent]

Of course the Panasonic type unit operates with pulses of power on each pedal stroke so the power can peak on each pedal thrust, the amount of the peak depending on rider input to the torque sensor.

That's amazing, I had no idea that the Panasonic system worked like this, but now I think about it this does make sense. It explains the overall responsiveness and feel of the system. No pedelec power cut off problems here.

One complication with electric motors of all sorts is that peak power output does coincide with peak efficiency. I wonder whether Panasonic have tried to design around peak power or peak efficiency.

I think all of this goes to show that it is incredibly difficult to quantify a question such as the one posed at the start of this thread "Is the motorised bicycle the most efficient road legal mode of motorised transport available to mankind?". It depends on which bike, over which course, how the bike is ridden and what is meant by "efficient".