One of the delights of being housebound with injuries is having the time to make all manner of interesting calculations about things that no normal person considers.
With daytime television failing to hold my attention for more than 30 seconds, the boys entertaining themselves and no new books to read, I decided to find out just what my cycling involves and how much power I produce.
The first task was to write down all the known figures:
- Combined mass of cyclist (me), bike and load: 189.5 kilograms
- My height: 177 cm
- Distance from school to croft: 3235 metres
- Rise in altitude from school to croft: 80 metres
- Distance of steepest section of journey: 200 metres
- Rise in altitude from beginning to end of steepest section: 20 metres
- Cycling cadence: 100 pm
- Time taken to complete the school-croft journey: 9min 45sec (mid point of fastest time of 9min 30 sec and slowest of 10min
From these, I calculated the percentage gradient (rise divided by step, multiplied by 100) of the entire journey and the steepest section.
Gradient of entire journey: 80/3235 x 100 = 2.47%
Gradient of steepest section: 20/200 x 100 =10%
Then I calculated average speed over that distance: 19.91km/h
Before launching off on my own, the next step was to find if someone had already put together a cycle power calculator - and they have, albeit without an upright trike so I used an upright tourer.
I started putting in all my figures for a journey from Insch out to the croft, added a 10km/h head wind (which would be typical) and then ran the calculation.
I was startled to say the least.
First, the steep, uphill gradient where I can just manage to maintain 10km/h, doing the 200 metres in around 1min 15sec.
It turns out I’m putting out 611 watts to maintain that speed up that stretch of road, and burning 4200 calories in doing so. (The UK recommended daily intake for men is 2500 calories.)
What about the entire ride home?
I do 3235 metres in a median time of 9min 45sec on an overall gradient of 2.7 per cent at an average speed of 19.91k/h.
When I run those figures through the calculator, I find that my power output over the entire journey is 532 watts, which requires the consumption of 2970 calories.
The journey into town, on the other hand, only requires the expenditure of 35 watts.
Of course, the power and energy consumption figures are only approximations, but it does illustrate how much effort is required to pedal a heavy trike more than three kilometres (two miles) uphill.
To judge how accurate the figures were, I looked up the typical amount of calories burned while cycling.
An 88kg rider doing 32km/h (20mph) in a race on the flat burns about 1400 calories an hour, but he may well be riding a bike that only weighs 7kg or so (the lower limit for racing is 6.8kg).
I’m an 80kg rider doing 19.9km/h on a 2.7 per cent gradient riding a bike with a total weight of 109.5kg (incuding front passengers and groceries).
What that means is that if you put me on the racing bike on the flat over the same distance, I’d been able to average 30km/h. That’s very good going.
But best of all is when you convert my peak power of 611 watts in horsepower and discover that I can put out 0.82hp for a short time.
That’s four-fifths of a horse. It feels like it at times…
strewth Stoney that’s why too much for us serial ‘house bounds’ to think about!
Hi,
I wanted to e-mail you but i can’t find an address.
I’ve recently setup a new website for Scottish Crofters and wondered if
A) You fancy a look…
B) if you would link to my site. I would be very happy to link to this site and even happier if you joined mine!
The web address is: http://www.forum.scottishcrofting.co.uk
Kind Regards
Neil, I’ve taken the contact form off-line for now as I was getting far too many vitriolic messages. Now, if anyone wants to get vicious, they have to do it publicly.
Unfortunately, that also means well-intentioned people also get cut off, but I may reinstate the form once all the crash hubbub has died down.
Hell’s bells - all those mathematic equations!!! Although when you were a growing lad you ate like the proverbial horse, which is probably why you are now only 4/5ths of one. Its the ageing process that reduces you!!! :=)
Yeah, i’ve had the same unfortunately.
Your For Sale page text made me laugh, hmm been there!
Thanks for posting my message i’m off to have a read of your other stuff.
Hmmm…… 4/5ths of a horse ….. that jogged my reading memory ….. aaah, here it is, just flashed into my mind …. There is a very interesting book about POW of the Japanese WW2, it is titled One Fourteenth Of An Elephant.
What was the 1/14th ? No I will not give the game away … read the book and find out for yourself folks.
On another tack Stoney, I am glad I walk that road and not push a large trike when I am visiting. Phew, just reading the report makes me reach for a cuppa and my next good book.
I read once that cyclists in the Tour de France eat over 6000 calories a day. I hope you’re eating enough!
Horses eat a lot of oats if they are working horses…..do you grow oats?
I had oats for breakfast, oats in my pancakes for morning tea and thickened my stew with oats. I also eat brose (made with oats), oatmeal biscuits and oatmeal bread, among other things.
I told you I was four-fifths horse!