cyclezealot

A couple days ago, Craft lite sleeveless weight undershirts were on sale.They are designed to 'keep you cooler.' Weave in fabric to push moisture up through a Coolmax Jersey.
Wore it two times so far...not sure, what I think..?
Sort of suspect, I fear it did not make me cooler..Couple more wearing on hotter days, before I make up my mind.....
Anyone here , wear Hi tech undershirts for hot days..
Do you think they helped to keep you cooler..All winter long I wear cycling undershirts to keep warmer....To keep cooler, Undershirts..? What do you think..Did it help...

xanatos

I'm no scientist, but a few things I would suggest as valid points:

1. Polyester (and other synthetic materials often used in jerseys) dry faster. I.e. they allow water to evaporate quicker. Now since the evaporation of water is an endothermic reaction (requires energy), this absorbs heat and cools your skin. Think of when you come out of a shower. This is the reason your body will feel cold (well, this plus the fact that most people shower with water warmer than room temperature)

2. Cotton (and most materials) also allows water to evaporate. However since cotton takes a long time to dry, at the end of a bike ride, your shirt may stay wet for quite awhile. So even after your body has cooled down, you will start to feel cold if you stay in the wind because water is still evaporating. Whereas even during my sweatiest times, my cycling clothes will dry quite quickly when I'm outdoors.

3. Due to 1. and 2., you definitely want to wear those synthetics during the winter. They are evaporating faster (which does cool you), but staying drier is much more important to keeping warm when you're sweating in the winter.

Does this answer the question? Hmm no. But it seems that various quick-drying syntetics let you cool as you cycle (as they evaporate more rapidly), and leave you drier when you want to be (shortly after workout).

-xan-

ultra-g

Seems like just another reason to spend $30. Hi-tech underwear.

If I had $30 to waste I'd definitely get it, but since I don't and I don't think Nike will ever give me a sponsorship deal, I'll wear my jersey with my nipples showing.

slvoid

Depending on humidity, if it's very low (a dry heat) a cotton shirt will hold onto moisture so it doesn't evaporate too quickly and keep the shirt cooler longer. (Hikers in the desert wear long sleeve cotton shirts to keep the sun off and their bodies cool).
But if humidity's high, then all bets are off and you might as well go synthetic.
During the winter however, dry as it may be, any liquid moisture tends to freeze or at least rob your body of heat as it evaporates. You'd want something synthetic to wick the moisture out as water vapor not a liquid.

cyclezealot

When I bought the undershirt,the clerk( a cyclist himself) said good investment...I think I understand the principal of the undershirt...But, unsure yet whether a second layer has no insulating factor. Try it on a warmer day.

dafydd

I would tend to dispute that to some degree. At the very least, it depends upon weave and cut. Ever wear Dickies pants during a nice humid summer? Might as well be wearing trashbags. Nylon and acrylic socks give me jungle rot, i try to wear as naturals on my feet as possible. Synthetics are warm, but many/most do not do wick.

Coolmax and Gore products do breath/wick well. But in terms of jerseys, i haven't found much difference between wool and coolmax. wool might take a little longer to dry but it doesn't give you chills as it does so. i do use coolmax socks for riding, mainly becuase it's hard to find short thin wool socks.

xanatos

dafydd, that's a very good point. I recently got some leg warmers by DeFeet that are 100% polyester, but actually don't seem to wick or dry that fast. So weave is a very important factor I think. However the problem with weave, is that it can be hard to tell how good a product is at wicking/drying until you've tried it.

cyclezealot

This Craft shirt does have an unusual weave in the material..Think many use a similiar product on really hot days alone and no jersey, particularily like under bibs. ..Maybe I will give that a try on a really hot day, when otherwise I would scrap the idea of a ride.

countryrider

I use Under Armour, and it works very well. It's wicking ability is good, and it keeps me cool. If you wear a jersey, get HeatGear in your normal size. It should be tight, that's the way it's designed. If you don't wear a jersey, but wear just a shirt get the Loose Gear. From what I know it has the same parameters as Heat Gear. It is just loose fitting as the name implies. If you order it, you may want to try a size smaller than normal, and order it from Eastbay.com I am not doing a solicited ad for them. They have an excellent return policy, and will get you the size you need if you find it fits improperly. Their shipping has also been fairly quick for me, but they are only 4 hours away in Wausau.

lotek 

I used a coolmax (kucharik?) sleeveless undershirt when I rode Hotter N' Hell
last year, and I do think it helps.
I wear one when I'm doing anything more than 10 milers here in texas
(we've been creeping towards the 100s all week).
If you notice, all the tour riders wear em even when its really hot,
gotta be doing something for em.

Marty

Flaneur

When I first started cycling, the old guys all wore undershirts, as an added layer of protection, in the event of a fall. The idea being that the two layers slide against one another and you lose less skin. I don't fall off much (and I'm not sure how I could adhere to the principle more fully without offending the underwear nazi!)but I still wear undershirts, regardless of temperature and humidity. Since the mid 80's this always means Helly Hansen 'Lifa' polypropylene vests, long or short sleeved- white in summer. I like them because:

-they seem to work at least as well as newer fabrics, and I never give up on a product until a superior one has proved itself.

-they crush down real small for touring.

-they rinse and dry with ridiculous speed (and can be worn wet, at a pinch).

-they're really thin and go under any kind of tight fitting garment, with ease.

Only drawbacks are they don't look good in a country club and they don't react well to careless (hot) washing programmes.

You crossover guys might be interested to know they are just as good in the French Alps (winter) and the Californian Sierra (july). They aren't so popular these days, but you still see them, like a lot of good products that marketing has overlooked, in faraway corners and strange bivouacs.

SteveE

I wear a DeFeet undershirt all year 'round. It seems to keep me warmer in winter and cooler in summer. I sweat alot and it keeps the moisture off my skin. Even in the summer it can be pretty chilly in the morning around here. Plus there is often coastal fog near the ocean. Last Sunday, after we had reached the top of a long climb and stopped for a regroup, my jersey was soaking wet but my skin was relatively dry because of the wicking action of the undershirt. I didn't freeze on the 4 mile descent down to the valley because the moisture wasn't next to my skin.