# base layer and hot weather



## Devastazione (Dec 8, 2011)

I've been using my Gore Bike Wear Oxygen shirts straight on my skin,does adding a tank top makes sense ? Not wind proof,not fancy,just the basic thank top Gore sells. I will resume my riding in semptember and temperature are still in the 25/35° celsius here. What say you ? Less sweating ? More sweating ? Dryer ?


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## joeinchi (Sep 24, 2010)

Anything over 25C (77F) and I'll use only a single layer.

I would only add a layer to increase warmth. I can't see how a tank would improve dryness and keep you cooler, though, there are many claims to that effect.

Body hair and humidity also play into such a decision, so it's hard to generalize. The best answer will come from trial and error to see what works best for your conditions, physiology and, of course, level of effort.


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## duriel (Oct 10, 2013)

I vote for a nice close shave, very cooling.


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## Devastazione (Dec 8, 2011)

'nuff said,you just saved me 34 Euro worth of gear I won't be using. Besides the late september hot weather the worst part is the tarmac still steaming out the whole spring/summer eat,so 25 feels actually 32 on the road.


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## JCavilia (Sep 12, 2005)

joeinchi said:


> Anything over 25C (77F) and I'll use only a single layer.
> 
> I would only add a layer to increase warmth. I can't see how a tank would improve dryness and keep you cooler, though, there are many claims to that effect.
> 
> Body hair and humidity also play into such a decision, so it's hard to generalize. The best answer will come from trial and error to see what works best for your conditions, physiology and, of course, level of effort.


Here's a discussion from a few weeks ago that might be informative. Or not 

http://forums.roadbikereview.com/general-cycling-discussion/nike-dri-fit-t-shirt-vs-cycling-base-layer-347433.html


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## El Scorcho (Dec 14, 2005)

I have 4 different base layers that I use during the summer, I started wearing them to keep my nipples from being sheared off by my bib straps. (bloody nipples are bad)

I can't tell the difference between the Defeet and the Giordana but the Craft and the Assos hot summer are great. I never ride without them so I don't have any real comparison to just riding with a jersey.


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## mikerp (Jul 24, 2011)

It depends on the base layer, some help, some do nothing, some do harm.


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## Marc (Jan 23, 2005)

mikerp said:


> It depends on the base layer, some help, some do nothing, some do harm.


It depends on where you live too.

If it is so damned humid that sweat all but ceases evaporating at all during summer (read most of the US midwest during summer), even a $700 Assos baselayer ceases to be anything more than another sopping wet rag on your body.


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## Adim_X (Mar 7, 2011)

I'm with El Scorcho, the base layer protects the nips from the bib straps.


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## mikerp (Jul 24, 2011)

Marc said:


> It depends on where you live too.
> 
> If it is so damned humid that sweat all but ceases evaporating at all during summer (read most of the US midwest during summer), even a $700 Assos baselayer ceases to be anything more than another sopping wet rag on your body.


Yes and No, being in Florida I see a high level of humidity year round, I can be working on the house yard and soak any regular outdoor clothing in short order. While on a bike I am seeing a good deal of wind which aids immensely with evaporation, it's like standing in front of fan vs. being in a room without any air movement. The heat/sweat only starts to be an issue when at a stop light/etc. As to Assos baselayers I have found them to be better other items, I guess I've been lucky as none have cost me $700.


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## Marc (Jan 23, 2005)

mikerp said:


> Yes and No, being in Florida I see a high level of humidity year round, I can be working on the house yard and soak any regular outdoor clothing in short order. While on a bike I am seeing a good deal of wind which aids immensely with evaporation, it's like standing in front of fan vs. being in a room without any air movement. The heat/sweat only starts to be an issue when at a stop light/etc. As to Assos baselayers I have found them to be better other items, I guess I've been lucky as none have cost me $700.


Here in Nebraska in high summer, you can have all the wind you can stomach...and it won't make the sweat evaporate, and you won't be any cooler.


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## El Scorcho (Dec 14, 2005)

Marc said:


> It depends on where you live too.
> 
> If it is so damned humid that sweat all but ceases evaporating at all during summer (read most of the US midwest during summer), even a $700 Assos baselayer ceases to be anything more than another sopping wet rag on your body.


I've lived in the desert my whole life, I don't know how you guys live with that humidity stuff. The humidity here was quoted as %4 one day last year, that's the lowest I've ever seen. Normally we are around 18-25%, maybe this is why I am such a proponent of the baselayer. Well, that and liking to keep my nipples.


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## skinewmexico (Apr 19, 2010)

El Scorcho said:


> I've lived in the desert my whole life, I don't know how you guys live with that humidity stuff. The humidity here was quoted as %4 one day last year, that's the lowest I've ever seen. Normally we are around 18-25%, maybe this is why I am such a proponent of the baselayer. Well, that and liking to keep my nipples.


Low humidity here, and I don't get the base layer thing. I want the sweat on my skin to evaporate, and cool me down, not my outer layer.


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## joeinchi (Sep 24, 2010)

There's a pretty good explanation written by JC in that other thread:


JCavilia said:


> http://forums.roadbikereview.com/general-cycling-discussion/nike-dri-fit-t-shirt-vs-cycling-base-layer-347433.html


What it comes down to is surface area. Say you spill a drink on a countertop and there's a small puddle. If you drop a paper towel on it, the liquid is absorbed and spread throughout the towel increasing it's surface area and rate of evaporation. If left alone, the puddle would retain its size and take longer to evaporate.

I think the concept is easier to understand with cold weather apparel. I'll often use a medium weight base layer to keep warm but it also keeps me cool by soaking up sweat and spreading it over a larger area. Pair that with a breathable shell or vest and the sweat evaporates pretty quickly and prevents you from overheating.

Unlike fall or winter, though, the cooling effect of moisture transfer is diminished by the discomfort of higher temps and presence of humidity. It's a sound theory but, for many, it's simply more comfortable to use a single, breathable layer on those warm weather rides.


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## JCavilia (Sep 12, 2005)

skinewmexico said:


> Low humidity here, and I don't get the base layer thing. I want the sweat on my skin to evaporate, and cool me down, not my outer layer.


In very low humidity, it doesn't make much difference. Essentially all of the water will evaporate from the skin, with or without a base layer. In humid conditions, wicking the water into a network that greatly increases the surface exposed to the air will increase the evaporation rate. In very hot and humid conditions, probably the best setup is a single layer, but made of a wicking material and fitted close to the skin.

YMMV. I have lived in both climates. I grew up in the desert (Reno) but now live in the humid Northeast (New England -- though I spent several years in the even more humid mid-Atlantic (D.C.)). I wear a base layer most of the time, but a single light wicking layer on the hottest days.

And to the OP, IME you don't have to spend a bunch of money to get effective stuff. All the wicking synthetics work similarly. However, a close fit is essential, so I alter the cheap underlayers I get from Sierra Trading Post, so everything fits perfectly.

BTW, 25-35 C is _perfect_ cycling weather in my book. Diff'rent strokes.


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