CityCyclingEdinburgh Forum » Infrastructure
Cycling- 84mpg
(11 posts)-
Posted 6 years ago #
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Someone will be along shortly to tell us exactly how many miles a cyclist gets to the equivalent gallon of fuel...
<neddie holds breath>
I'm gonna guess around 1000
Posted 6 years ago # -
Calculation widely use (some years ago) was about 1500.
Posted 6 years ago # -
Petrol has at most 34.2MJ per litre so 155MJ/gallon.
Punters like us might be using 500W to generate 100W of useful power in the drivetrain while riding steadily at 20km/h.
So that's 1.8MJ to go 20km. The gallon equivalent distance is 1722km or 1000 miles near enough.
Posted 6 years ago # -
Nice!
Posted 6 years ago # -
Ahh you mean 500W worth of food to generate 100W of useful power on the bike.
I spent a while checking that I wasn't going crazy remembering a drive chain is ~95% efficient..
Posted 6 years ago # -
Drive chain good human body bad.
IWRATS not show full working and narrative sketchy. 7/10.
Posted 6 years ago # -
@toomanybikes: Ahh you mean 500W worth of food
Every time someone confuses power and energy, God kills a puppy.
IWRATS correctly calculated the energy required to ride 20km at 20kph based on an energy consumption rate of 500W to maintain said speed. His estimates of the mechanical power output and the chemical to mechanical energy conversion efficiency of the human body seem to be pretty much on target, based on some quick Googling. So roughly 1,000mpg equivalent seems about right.
If you wanted to delve further I suppose you could go further back down the energy chain and look at the energy efficiency of food production & delivery processes vs the well-to-pump energy efficiency of the gasoline supply process. (For example, during my Googling I found a figure of 1.5% efficiency for conversion of sunlight in to chemical energy in an Iowa cornfield. Amazing what you can find online.) You could also look at the energy costs of production for the vehicles involved (bikes win over cars by a country mile), provision of infrastructure required to make those vehicles usable (ranging from, in the extreme case, near enough zero for an MTB to "quite a bit more than that" for most motor vehicles) etc etc.
I'm sure someone, somewhere, is working on it right now...
Posted 6 years ago # -
IWRATS correctly calculated
Take that CCE. <IWRATS does weird victory dance>
near enough zero for an MTB
Not in North Britain. Quite impassable in its native state. All paths hard won.
Posted 6 years ago # -
Great points, ejstubbs.
Now I'm dying to know the figures for all the other factors...
CCE, go to work!
Posted 6 years ago # -
The carbon balance for an Iowa corn field will be interesting, including the natural gas fueled Haber-Bosch process and the agricultural diesel without which pretty much nothing.
Posted 6 years ago #
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