to wear fleece from start of journey?

[ventoux50]

Deciding what clothing to wear is a tricky number.



Firstly, the insulation properties of the clothes should be known. Cotton fabric have a coefficient of 0.03 (W/m.K) when its damp with sweat.



The amount of energy transmission is ( the coefficient / thickness of fabric m ) * area exposed to windchill * ( Neutral Skin Temp – Equivalent Skin temp according to the Windchill factor ).



Example ( 0.03 / 0.001 ) * 0.41 m^2 * ( 33 – 6.40 Deg C ) = 330 Watts = 4.7 kCals per minute being sunk away by the damp 1 mm thick cotton shirt.

Yes I agree, in fact without fail, every time I consider riding I sit down for an hour and analyse the properties of the clothing I intend to wear and contrast that with the readings from my recently installed meteoroeloegoical weather measuring equipment in the back garden.

I couldn't ride without it !

 

[jimboalee]

Let me give you another example.



The ambient temp is 2 deg C. We are riding into a 10 mph headwind so the closing windspeed is 24 mph.

We have decided to wear 2.5 mm of clothing over ALL our torso, arms and legs.



( 0.03 / 0.0025 ) * 0.42 m^2 * ( 33 – -5.50 Deg C ) = 194 Watts = 2.8 kCals per minute being sunk away by the 2.5 mm thick cotton kit.


As can be seen, 3 layers of cycle jerseys, or a base layer + thick fleece and Tudor Longs is sufficient to be comfortable indefinitely in winter conditions.

What you have to have Ventoux50, is a spreadsheet which accepts the Amb temp, windspeed and direction; and the direction of travel.

Easy peasey.

Is your Avatar a good self likeness?

 

[ventoux50]

Interesting calculations Jimboalee, many thanks for enlightening us, however, I can't see that you consider the effect of the coefficient of sweat evaporation versus percentage of skin exposed to air..... surely this is an inmportant consideration and would have a perceptible effect on the overall results.

I bring this to your attention not to besmirch your admirable work, merely to add something tangible to it.

Yours in science

V50


P.S. it's not an avatar its a self portrait

 

[ianrauk]

Let me give you another example.



The ambient temp is 2 deg C. We are riding into a 10 mph headwind so the closing windspeed is 24 mph.

We have decided to wear 2.5 mm of clothing over ALL our torso, arms and legs.



( 0.03 / 0.0025 ) * 0.42 m^2 * ( 33 – -5.50 Deg C ) = 194 Watts = 2.8 kCals per minute being sunk away by the 2.5 mm thick cotton kit.


As can be seen, 3 layers of cycle jerseys, or a base layer + thick fleece and Tudor Longs is sufficient to be comfortable indefinitely in winter conditions.

What you have to have Ventoux50, is a spreadsheet which accepts the Amb temp, windspeed and direction; and the direction of travel.

Easy peasey.

Is your Avatar a good self likeness?

No, please don't

 

[jimboalee]

Interesting calculations Jimboalee, many thanks for enlightening us, however, I can't see that you consider the effect of the coefficient of sweat evaporation versus percentage of skin exposed to air..... surely this is an inmportant consideration and would have a perceptible effect on the overall results.

I bring this to your attention not to besmirch your admirable work, merely to add something tangible to it.

Yours in science

V50


P.S. it's not an avatar its a self portrait

Indeed it does, and calcs get more complex when 'Solar gain' is thrown in during a hot sunny rando.

 

[jimboalee]

No, please don't

Message understood....