Yet, yet another gem.
- Thread starter jimboalee
- Start date
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beancounter
Well-Known Member
- Location
- South Beds
zzzzzzzzzzzzzzzzzzzzzzzzzzz
gaz
Cycle Camera TV
- Location
- South Croydon
is that true for all speeds?
so if ur doing 2mph, ur actually going backwards!!
so if ur doing 2mph, ur actually going backwards!!
ColinJ
Puzzle game procrastinator!
- Location
- Todmorden - Yorks/Lancs border
Now that is actually a subject that I've been wondering about! No, seriously...jimboalee said:
On the flat, with no wind, I can only cycle at 33 mph for a short time. Now if there was a 30 mph headwind, would that mean that I would only be able to move forwards at 3 mph (i.e. very slowly) for an equally short time? I know that it would be very hard work, but would the two be equivalent?
Intuitively, it seems as though they would be equally hard but you are saying that this is not the case. Okay then, that's interesting - what is the reason for the difference?
ColinJ
Puzzle game procrastinator!
- Location
- Todmorden - Yorks/Lancs border
Perhaps you misunderstood thejimboalee said:
- I genuinely want to know - why would riding at 33 mph on a still day not feel the same as riding at 3 mph into a 30 mph headwind? It would be handy if this was true because otherwise an 18 mph headwind would pretty much make most of my rides impossible for me.
Steve Austin
The Marmalade Kid
- Location
- Mlehworld
I want proof of this "fact"?
ColinJ said:Now that is actually a subject that I've been wondering about! No, seriously...
On the flat, with no wind, I can only cycle at 33 mph for a short time. Now if there was a 30 mph headwind, would that mean that I would only be able to move forwards at 3 mph (i.e. very slowly) for an equally short time? I know that it would be very hard work, but would the two be equivalent?
Intuitively, it seems as though they would be equally hard but you are saying that this is not the case. Okay then, that's interesting - what is the reason for the difference?
I'll just comment on this one response.
If 33 mph is the edge of your envelope and no more power can be mustered ( nearly 1 kW ), a 30 mph headwind would probably reduce your speed by half, or to 16.5 - 17 mph. A headwind of equal and opposite speed would get your speed to half ( for the same power ).
Although you have a Cd figure of somewhere around 0.85 for a racebike or 0.95 for a tourer, you are not a flat sheet of plywood stood face-on into the breeze. Your body in the tuck has some streamlining.
On an Audax in Staffordshire about ten years ago, the headwind was against the riders straight away from the start. I usually ride at 30 kmh through still air; and the wind was dead against us at over 15 mph.
If all the other riders and I had not 'given a little extra' all the way to the first control, we would have all been out of time.
To get to that first control with time spare to eat five slices of fruit cake, we needed to double our power output.
It was one of the rare Audax rides where I took a bottle of heavily sugared Ribena.
I can't speak for the other members of this forum ColinJ, but I like to know how tough a ride is going to be and prepare for it.
MacB
Lover of things that come in 3's
- Location
- Farnborough, Hampshire
rich p said:
Hmmm, wonders if Jim has a formula to 'turn on' RichP, not even sure I should be wondering that sort of thing
