Is it just me, or is the wind NEVER behind you?

[Arch]

I rode from Lindisfarne to Wooler once, about 20 miles, into the wind all the way, with a friend. We had to pedal downhill.

By the time we got to Wooler I was so exhausted, I had to walk, because I couldn't ride fast enough to stay upright. We struggled up to the Coop, and my friend left me standing in the aisle, while he collected stuff for dinner at the hostel, pasta and sauce. He came back to ask if he should get cheese too, and I replied "I don't care".

Anyone who knows me, knows that me not caring about cheese is a short step from death.

Once we got back to the hostel (at the bloody top of town!) and I had a cup of tea and a bucket of pasta, I was ok, but oh, it was hard work!

 

[totallyfixed]

Seriously! It's always hindering me, never helping. I don't get it! Common sense says if the commute in is harder, the commute home should be easier (if the wind is still blowing) but somehow it never seems to work that way...

If you cycle a squarish route, say 20 miles, the wind will only be a tailwind for 5 of those. If you average 15mph for the head wind and side wind legs that will take 1 hr and if for the tailwind leg you average 20mph it will take you just 15 mins. So for the whole ride you only had a tailwind for 20% of the time and of course enjoyable things never seem to last long.
I may be making this up as I go along

 

[rowan 46]

Here you are glad to help everyone

 

[CopperCyclist]

No such thing as a tailwind. That's a scientific fact. Headwinds are awful. Sidewinds are even worse, when you have to ride leaning to one side as a counter balance.

Had strong side wind most of the way not work today, shoving me hard into the gutter most of the time. It slowed me down just as much as the headwind too. I'm trying hard to consider it the world trying to help me lose the pounds that I put on on my recent holiday...

 

[slowmotion]

I always felt that even if a wind is technically a 'tailwind', if you're cycling faster than the wind it'll feel like a headwind since you're catching up with it. I.e 15mph tail wind, travelling at 25mph = 10mph headwind? Of course I may just be talking out of my behind.

Maximum respect!


That really is blindingly obvious after you pointed it out.

Chapeau that man...

 

[rowan 46]

Maximum respect!


That really is blindingly obvious after you pointed it out.

Chapeau that man...

It does seem blindingly obvious but it's not true unfortunately. windspeed is the reason why the land speed record is measured over 2x 1 mile trips going opposite directions and averaged. Thus negating somebody taking advantage of favourable winds. If wind speed has an advantage to a car travelling at 700mph then there is an advantage to a cyclist travelling at 40mph? my guess is it's a perception thing as has been hinted earlier. when the wind is behind us we just think we are brilliant cyclists.

 

[thefollen]

Looking forward to the cycle this morning. Yesterday was a 'beers' day so left the bike at home. Alas from my bed it doesn't sound as though the wind is howling as much as yesterday but can still hear a decent rustle of foliage!

Does anybody cycle down Millbank/Grosvenor Road from Whitehall to the Chelsea Bridge here? I do on the way back and you usually get a big blast of wind in the face when the Thames opens up. Challenge is to keep it above 20!

Due to do a few laps of Richmond park on Sunday also- on a windy day the wind always appears to hit on the uphill stretches. I see it as a great training aid, even if with me at 60kg it tries to bully me a bit ;-)

 

[Norm]

I have confusion...

It does seem blindingly obvious but it's not true unfortunately. windspeed is the reason why the land speed record is measured over 2x 1 mile trips going opposite directions and averaged. Thus negating somebody taking advantage of favourable winds. If wind speed has an advantage to a car travelling at 700mph then there is an advantage to a cyclist travelling at 40mph? my guess is it's a perception thing as has been hinted earlier. when the wind is behind us we just think we are brilliant cyclists.

Why do you say that it is not true and then prove that it is.

 

[thefollen]

It does seem blindingly obvious but it's not true unfortunately. windspeed is the reason why the land speed record is measured over 2x 1 mile trips going opposite directions and averaged. Thus negating somebody taking advantage of favourable winds. If wind speed has an advantage to a car travelling at 700mph then there is an advantage to a cyclist travelling at 40mph? my guess is it's a perception thing as has been hinted earlier. when the wind is behind us we just think we are brilliant cyclists.

Think I may have chosen the wrong terms- should really have referred to it initially as 'wind resistance' as opposed to 'headwind' or 'tailwind'. Not being a physicist I have no idea regarding the calculations, may be completely wide of the mark and sound rather thick... but here's my tuppence

I guess air has a certain density to it (does this vary due to high/low pressure?) and cycling on a completely still or minimal wind day you'll encounter resistance as you collide with the air particles (you the cyclist create the collision by moving into it).

On a day with wind I'd imagine this collision differs as the air particles are moving at x speed in x direction affecting the degree of resistance you'll encounter. I still believe if you're traveling at 25mph with a 15mph tailwind the resistance would be the equivalent to a 10mph headwind since you're colliding with the air at 10mph. If the tailwind is faster than your speed the air particles would experience resistance in you and you'd feel the wind 'pushing you along'.

With a land speed record it may be the case that there's an accepted level of wind resistance for it to be valid?

This morning was a nice fresh cycle anyway, I'm expecting to be hit by the wind going back south later!

Bacon sandwich time.

 

[JamesAC]

I think it is the case that when you have a tail wind (ie the wing is blowing faster than you are cycling), then the boost given by the wing is proportional to the square of the wind's apparent velocity (ie F = k(V^2)), whereas if you're cycling into headwind, then the resistance is proportional to the cube of the wind's apparent velocity (ie F = k(V^3)) (where F = force, V is apparent velocity and k is a fiddle factor)

 

[thefollen]

It'd be awesome if a speedo had a wind speed readout and direction indicator. Do these exist?

 

[Norm]

They do exist - check out chandleries and other yachtie haunts. You can get hand held ones and others which fix to a pole.

However, they measure apparent wind speed and direction.

 

[JamesAC]

They do exist - check out chandleries and other yachtie haunts. You can get hand held ones and others which fix to a pole.

However, they measure apparent wind speed and direction.

But isn't that the important thing? A tail wind of 10 mph becomes a head wind of 10 mph if you're cycling at 20 mph in the same direction. And if the wind is blowing towards you at an angle of 45 degrees, then, err, err, you do something with sines. Or cosines. Or am I going off at a tangent?

 

[malkie]

I am assuming that I *may* have had a tailwind yesterday on the last bit of my commute whilst travelling at 37.5 mph on the flat.

On the other hand got to love pedalling downhill just to keep moving whilst swearing at god .

 

[BrumJim]

But isn't that the important thing? A tail wind of 10 mph becomes a head wind of 10 mph if you're cycling at 20 mph in the same direction. And if the wind is blowing towards you at an angle of 45 degrees, then, err, err, you do something with sines. Or cosines. Or am I going off at a tangent?

Tangent, clearly. Your direction is the adjacent side, the side wind is opposite side, and hence the apparent wind angle is the arctangent of bike speed over wind speed. Pythagoras gives you apparent wind speed. And add a cosine if the wind is at 45°.