Cycling and bicycle discussion forums. 
   Click here to join our community Log in to access your Control Panel  


Go Back   > >

Singlespeed & Fixed Gear "I still feel that variable gears are only for people over forty-five. Isn't it better to triumph by the strength of your muscles than by the artifice of a derailer? We are getting soft...As for me, give me a fixed gear!"-- Henri Desgrange (31 January 1865 - 16 August 1940)

User Tag List

Reply
 
Thread Tools Search this Thread
Old 06-26-07, 09:08 PM   #1
dijos
Walks with a limp
Thread Starter
 
dijos's Avatar
 
Join Date: Nov 2006
Location: St Pete
Bikes:
Posts: 1,341
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
are lighter colored bags cooler?

I mean in the literal sense, do they stay at a lower temperature in the sun? I have a black and grey bag, and the contents get pretty hot in the summer here (it's freaking hot+the sun is incredible) I also sweat my behind off. I was thinking of avoiding black and thinking about the overall impact of having a lighter color (like red) or way light( like white).

any thoughts on this?
dijos is offline   Reply With Quote
Old 06-26-07, 09:11 PM   #2
Sekt
Arrr!
 
Sekt's Avatar
 
Join Date: Oct 2005
Location: Hobart, Australia
Bikes:
Posts: 246
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Black will definitely get hotter, and anything inside will get hotter as a result. On a hot day, a lighter coloured bag probably wont make a great deal of difference when it comes to sweat.
Sekt is offline   Reply With Quote
Old 06-26-07, 09:31 PM   #3
wearyourtruth
Ride for Life
 
wearyourtruth's Avatar
 
Join Date: Jun 2004
Location: Baltimore
Bikes:
Posts: 2,729
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
as far as sweat on your back i doubt it will have much effect, since the main source isn't the heat of the bag but the lack of breathability between the bag and your back

as for the contents, heck yes it will make a difference, depending on how long it's out in the sun. if you never ride more than 10 minutes it might not make much of a difference but if you are out in the sun for hours then it totally will help keep the stuff inside cooler
wearyourtruth is offline   Reply With Quote
Old 06-26-07, 10:24 PM   #4
garagegirl
Senior Member
 
Join Date: Mar 2006
Bikes:
Posts: 623
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
If you do try it, go for white. I would imagine Red or something similar will still absorb a fair amount of light/ heat compared to white. But your back will still get sweaty, you're wearing a giant plasticy object.
garagegirl is offline   Reply With Quote
Old 06-26-07, 10:50 PM   #5
EyeRobot
Fell off the Sober Sofa.
 
EyeRobot's Avatar
 
Join Date: Jan 2007
Location: Gainesville, Florida
Bikes: Independent Fabrication Deluxe XT, Club Fuji Dura Ace... Specialized Stump Jumper, Trek 930, Cannondale M300... who knows what the cat will drag in next?
Posts: 193
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
I had a white bag. It's brown now.
EyeRobot is offline   Reply With Quote
Old 06-26-07, 10:53 PM   #6
operator
cab horn
 
Join Date: Jun 2004
Location: Toronto
Bikes: 1987 Bianchi Campione
Posts: 28,306
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Quote:
Originally Posted by EyeRobot
I had a white bag. It's brown now.
lolcats
operator is offline   Reply With Quote
Old 06-26-07, 10:57 PM   #7
doomkin
Senior Member
 
doomkin's Avatar
 
Join Date: Apr 2007
Location: illinois
Bikes: surly steamroller - towniefied.
Posts: 549
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
personally i think all the black vs white stuff is bull****.

for example, canon claims that they make their telephoto lens white so that there will be less thermal expansion when their lenses are exposed to the sun. now, if black lenses expanded and distorted images when exposed to massive amounts of sunlight, it'd be a pretty well known fact. but it's not, because its a non-issue.

basically, unless you're taking cars and bunkers, color doesn't really matter that much. thermally.
doomkin is offline   Reply With Quote
Old 06-26-07, 11:01 PM   #8
Daijoubu
Senior Member
 
Join Date: Apr 2005
Location: Montreal QC, Canada
Bikes:
Posts: 172
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
It's a fact, go outside on a sunny day and grab yourself a black shirt and white tshirt, leave it a couple minutes and see which one is hotter
Daijoubu is offline   Reply With Quote
Old 06-26-07, 11:14 PM   #9
doomkin
Senior Member
 
doomkin's Avatar
 
Join Date: Apr 2007
Location: illinois
Bikes: surly steamroller - towniefied.
Posts: 549
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Quote:
Originally Posted by Daijoubu
It's a fact, go outside on a sunny day and grab yourself a black shirt and white tshirt, leave it a couple minutes and see which one is hotter
I had heard (via my high school physics teacher) the black clothes will keep you cooler than white clothes. Is this true?

An extensive and detailed study (Walsberg, Campbell, & King, 1978. J. Comp. Physiol. 126B: 211-222) examined different colors of bird plumage under different temperature conditions--with the added wrinkles of examining whether the plumage was fluffed or flattened, and varying the wind speed.

Under cold conditions with no wind speed, black, flattened plumage held in heat the best (though barely, compared to fluffed black plumage). Under hot conditions with no wind, white, fluffed plumage let heat escape the best. Both pretty logical findings.

But once the wind picked up, the results changed dramatically. With even a modest wind (anything above 3 m/s, or about 7 m.p.h.) fluffed white plumage exhibit the lowest net heat loss. This explains the large number of arctic animals that are fluffy and white. It's not just camouflage.

At high temperatures, as I say, white is best at not transmitting solar/ambient heat to the skin when windspeed is zero (only barely better when fluffed). However, with an increase in windspeed (again anything above 3 m/s), fluffed black plumage is the best at reducing the amount of heat transmitted to the skin. Flattened black plumage is the worst in terms of heat gain no matter what the windspeed.

What this means is relatively straightforward: black clothing absorbs sunlight and the heat radiating from your body, but if it is loose-fitting, and there is wind, the wind convects the heat away faster than it is absorbed. White clothing reflects sunlight, but also reflects internal heat back towards your body, so the net effect under identical conditions is less cooling than if you wore black. While it's true you don't often find fluffy black animals in deserts, you don't find many white animals, either--typically you find animals that blend into the background. So it appears that if heat gain and camouflage are in conflict, the need to avoid predation outweighs other considerations. On the other hand, desert-dwelling nomadic people such as the Tuaregs wear loose-fitting black clothing, and have been doing so for a very, very long time. If there were an advantage to wearing white clothes, you'd certainly expect they'd have figured that out by now.If you are packing for a trip to the desert would it be better to pack light or dark clothes? The answer is not a simple as you might think, as Don and Yael discuss.


Link.

Basically it states that in a static test, then yes, black warms up faster than white. However, if the black is fitted loosely and there is wind then it cools faster than white.

I read this as saying that if you're using a loose fitting messenger bag, over say a tightly drawn back pack, and you're moving along quickly on your bike instead of walking down the street, then the fit of your bag and amount of wind you're generating will produce a cooler ride.
doomkin is offline   Reply With Quote
Old 06-27-07, 12:31 AM   #10
schnee
Senior Member
 
Join Date: Sep 2005
Bikes:
Posts: 3,367
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
A messenger bag is not 'fitted loosely' to the contents, and doesn't have the same airflow. Also, bag contents do not have the same heat regulation systems of humans (i.e. they don't sweat). The situations aren't the same at all.

Be very careful of taking a scientific conclusion for one thing and applying it too broadly.
schnee is offline   Reply With Quote
Old 06-27-07, 12:34 AM   #11
danish
left treadle forward
 
danish's Avatar
 
Join Date: Jan 2006
Location: east kensington, phila.
Bikes: <strikethrough>BFSSFG IRO</strikethrough>, 197X Raleigh Record Ltd conversion, Java SS
Posts: 407
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
just don't put mayonnaise in your bag and you'll be fine.
danish is offline   Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off



All times are GMT -6. The time now is 07:28 PM.