How many of you wear a base layer? I understand wearing one when you need something to keep warmer. But what is the point when it is warm outside?

I don’t see why you would in hot weather. At least I never do. When it’s cold, a layer of merino wool under my long sleeve jersey is the best thing ever.

Sun protection, and especially when it's dry the fabric can spread your sweat out over a wider area of your body so it's evaporates more quickly. I wear one when I need the UPF.

I wear a base layer year round. In warm weather (up to 100 degrees F give or take so far) it works great for wicking the sweat away from my skin and keeping me comfortable.

For summer I wear a Craft sleeveless baselayer. In winter, I have long and short sleeve merino base layers to wear.

You're not always going to be hot even when it's hot out. A base layer can help regulate temperature.

Also some of my bib straps and jerseys feel scratchy against bare skin.

I live in the south with brutal humidity and I wear a Castelli mesh baselayer and I keep my jersey zipped down about halfway. It works as an evaporate air conditioning system that houses in the desert have. The air is cooled as it flows through the wet mesh. They absolutely work (or I wouldn't wear it). It keeps your skin from getting wet and clammy and sticky and your jersey doesn't get as soaked. They're light and thin, you can literally ball it up in your fist. It's one of those "don't knock it until you try it" deals.

I also ride sportbikes and in the summer I wear a cooling vest under my perforated leather jacket. It's a vest you soak in water before you put it on and it's like having a mini AC system.

Always. Insulated (thin) short sleeve for winter, wicking waffle weave type for summer. Winter is about staying warm and wicking sweat off the body to prevent chills, and in summer about wicking sweat to the outside to evaporate to stay cool. Works much better than a jersey alone.

I wear them. I have a few from Voler and Craft. The Craft mesh is significantly nicer than Voler in fit and material.
None of them keep me dry in the summer, but I still wear them because I like to unzip halfway and take advantage of the cooling feel since the baselayer is wet.

Baselayers do nothing to keep my jerseys dry. If I sweat, I will sweat and it wont magically stay at the baselayer level. I wear clothing that is next to my body for moisture transfer blah blah yada yada, but the technical BS is just that for me- BS. In the end it doesnt keep me cool or dry.
I dont think it makes me measurably warmer though.

Yes. Year round. Bib straps and zipper flaps chafe. Good quality and skin-tight fit are essential.

Always. I have winter base layers and summer base layers and everything in between.

https://www.underarmour.com/en-us/p/...r%20Collection

The compression fit works well for me.

Mostly it's about looking Euro-cool when you unzip and let the jersey fly.

I do have one hot weather mesh base layer, but with my jerseys and my riding conditions, I can't say that I've noticed any improved cooling effect. But others swear by them, so give 'em a try and see what you think.

I’ve learned something today. I didn’t know these hot weather base layers were a thing. Will have to look into adding one to my biking wardrobe, because it’s been stupid hot here, but I still like to ride.

Thanks for the good question, Stanley1!

It's interesting how the same question can get a different predominant response. Other times, this has gotten more of "no way that's stupid' type of feedback.

I almost always wear a base layer, & think one of the main advantages is less dehydration because of more efficient cooling.

Got a couple of those on your recommendation last summer. They're good and could be found for about $18.

Base layers winter or summer are a good thought. Summer riding in Texas can be more than hot. When the temps in three digits the pavement can bake you from below. You need sun protection on your arms and legs and insulation.

I have to sacrifice speed by wearing light colored loose clothing top and bottom and the speed reduction is significant. If its really hot I might wear a light cotton T-shirt underneath and a pair of thin liner shorts under my spandex to protect against heat rash. My wife was looking at me funny last year when I had to get a ride in and it was about 102°F. I had my light weight loose cotton stirrup pants on and a long sleeve white shirt with a cravat under my helmet to protect my neck. She laughed and said you look like your going to go pick water melons in the valley. Yep... I got my ride in...

As to the OP: Yes I wear a base layer when Hot or Cold. I don't like to but I do. Kinda like my helmet...

Yes I wear Under Armor Heat Compression tank tops. At least I think that's what they are called. I like the fact that they help protect against bib straps and zipper chafes. Plus they wick the sweat away from my skin which is a bonus.

Mirror fabric cools wearer by 5* C

🙂

Give it a few years.

The philosophy behind a base layer in heat is vaguely like the fins on a radiator: you are increasing the overall surface for heat transfer by making it three-dimensional.

On the other hand summer jerseys are already designed to do that so it is not clear to me how it is going to add much if you already have a mesh jersey that wicks well. And there is a trade-off of more fabric meaning more insulation and heat retention vs more fabric meaning more surface area for evaporative cooling.

So far I have not used a base layer in heat. If they were $5 I'd buy one and try it out. I recently watched some pro bike races in heat and recall seeing a lot more bare unzipped chests than unzipped jerseys with base layers showing.

It appears that the Tour guys don't wear them.

Some do. It's a personal preference thing.

I really like hydrophobic, skin-tight mesh undershirts. I have a shirts from Craft and Giordana I wear most often, the cheap ones from Amazon are fine too. I'm a particularly heavy sweater and prone to salt-buildup and chafing. On long rides this can become such an issue that I almost need to stop. I find I can can wear mesh undershirts even on the hottest days and they prevent any chafing of my upper body. I don't find they make me much warmer.

I prefer a base layer for comfort all year round and I wear them on the indoor trainer without a jersey too. Assos are my favourites, summer and fall versions. Summer base layers provide additional sun protection too.

IMO it depends on how loose your jersey is. If your jersey is skin-tight, and for hot weather it should be, then adding a baselayer simply increases insulation. If your jersey is loose, so that it's not saturated with your sweat, a baselayer might help if you unzip half-way so you can get air over it. I've tried it both ways. The biggest difference is of course when climbing when there's not as much airflow. The closer your sweat is to airflow, the faster it will evaporate. When I take off my tight climbing jersey, it's dry by the time I get it off.. I ride in a dry climate which can get quite hot.

Part of the reason I asked the question is that I have a base-layer garment that I bought probably 20 years ago. I bought it to help me, I thought to stay warm. When I wore it, in 55-60 degree weather I found that I froze myself. I had thought that it was was for cold weather since it had a long sleeves. Obviously, I discovered that this was intended for warm weather. I hardly wore it since. But after all this conversation I wore it this week on a day when the temperature was 80 and the humidity was very high. Must admit, that it kept me cooler. There is the bulkiness of an extra piece of clothing. But I was surprised that overall it felt cooler.