Matters Mathematical

[GaRRy]

Neptune:

Is this graph helpful? I have drawn 4 curves for bike speeds of 6 mph to 12 mph. 12 mph into a 30 mph head wind needs 633 watts - so that would not achieved by those on legal pedelecs.


The hill slopes are percentages, for example 10% means 50 foot climbed in a horizontal distance of 500 feet.

I hope this graph will be useful to the people in Lincolnshire in order to compare their speed on the flat into ferocious head winds to equivalent hill climb slopes about which which we in more hilly areas are inclined to boast.

6ft 8 1/2 inches and only 10 stone !!! why is this obviously super fit lazy ****** using a ebike

A graph for 5 10 and 16 stone would be more useful

 

[10mph]

6ft 8 1/2 inches and only 10 stone !!! why is this obviously super fit lazy ****** using a ebike

A graph for 5 10 and 16 stone would be more useful

GaRRy,
You are a hard task master. It took me an hour to plot that graph, now you want two more.

There is a short cut if you can do multiplication and division. Use a calculator if you can't do it in your head:

Assuming the 10 stone rider, which was requested by Neptune, I plotted for a bike + rider mass of 188 lbs.
A 16 stone rider will give bike +rider mass of 272 lbs, so divide the slope by 272/188= 1.45. I will leave you the problem of working out the multiplying factor for a 5 stone rider.
​

 

[GaRRy]

Ah but you have forgot to take into account that 16 stone rider will also a worse drag coefficient.

Dont worry I dont want another chart just wondered why rider was only 10 stone and 6ft 8 !!!!

 

[10mph]

You are right. According to the calculator, the 16 stone rider has 16% more effective crossectional area than the 10 stone rider. So the equivalent slopes will be decreased by about that factor.

 

[flecc]

Nice graph 10mph, though like Gerry I immediately wondered abut the chance of finding a 10 stone rider of that height in the e-biking world, or indeed almost anywhere these days! I'm a slim barely over 10 stones at just about 5' 6".

As you suggest, I suppose the graph might be interesting for someone on a flat area to compare performance with those in hilly areas, but it certainly shows the mismatch between the factors and how much more power hill climbers need in realistic circumstances. 12 mph against an appreciable 10 mph headwind only equals a barely perceptible 2% slope.

 

[10mph]

I immediately wondered abut the chance of finding a 10 stone rider of that height in the e-biking world, or indeed almost anywhere these days! I'm a slim barely over 10 stones at just about 5' 6".

When I took up biking again in 1991 for the purpose of measuring. I was 5 foot 10 inches and my weight was 10 stone, or sometimes 10 stone 4 lbs, when I loaded up for a very long run. I found that the bike which I then used did not provide a hard exercise session in comparison with running. I would never have dreamt then of needing an e-bike.

In 1999 when I measured the 54 mile London to Brighton race I had to walk up the road in the North side of Ditchling Beacon. My weight had not gone up much but my output power was falling.

Now, at about 13.5 stone and much weaker, I am grateful for the availability of some e-assist, even at a modest 10 mph.

In fact in the early hours of tomorrow morning, I shall be relying on e-assist to carry me around the Olympic Marathon course as I join the official measurer from the USA. I will try and get a photo and report back on how I coped on my e-bike alongside younger and fitter measurers.

 

[flecc]

In fact in the early hours of tomorrow morning, I shall be relying on e-assist to carry me around the Olympic Marathon course as I join the official measurer from the USA. I will try and get a photo and report back on how I coped on my e-bike alongside younger and fitter measurers.

That's going to be interesting, though if you use your usual measuring speed of 10 mph, it shouldn't be too taxing. Fortunately the weather forecast for London is for a break from the rain tomorrow.

 

[neptune]

@10mph. I am very grateful that you spent an hour plotting that graph. That is exactly what I had in mind. Personally I am 5 feet 7 inches and weigh about ten and a half stone , so its not too wide of the mark . The graph is a very good way of showing a lot of information , in a small space. Much of the time I ride my pedal bike, which is of course much lighter, but my ebike is very heavy , being a Powabyke Euro with lead acid batteries. I used to use the ebike like an electric moped , but since I fitted a larger chainwheel, I pedal a lot more to gain higher average speeds and greater range .
What can I say about your circumstances? We all loose fitness as we get older, it is inevitable . However you, like so many members here, are determined to make the most of where we are at today . Long may it continue!
Back in the 1960s I knew a girl once who 10 stone and 6` 8" tall. But about 18" of that was her 1960s hairdo.

 

[flecc]

Back in the 1960s I knew a girl once who 10 stone and 6` 8" tall. But about 18" of that was her 1960s hairdo.

Her name wasn't Marge Simpson was it?

 

[Davanti]

Her name wasn't Marge Simpson was it?

Oh No! Marge's name keeps cropping up!