As indispensable and overlooked as the gilet, the undervest is the only piece of cycling kit that comes with me on every single ride, year round, in hot, in cold, in wet, or in dry. While one could be forgiven for assuming an undervest lives out its life as an insulation layer, the undervest serves a critical, more fundamental purpose: as a wicking layer.
If you’ve ever had the misfortune of carrying a gallon jug of water, you will have noticed that water is not particularly light, nor particularly dry. If you’ve suffered the further indignation of having said gallon jug of water poured over your head after making a pithy remark, you will have noticed that the introduction of water to your clothing makes them both heavier and less warm. As cyclists, these characteristics don’t do much for us in the way of making our sport easier from the perspective that sweat is made up largely of water and thus has a tendency to make the clothing we’re wearing both wet and heavy. Enter the base layer, whose specialty is not so much in keeping us warm, but keeping us dry.
If I’ve understood physics correctly, these magical fabrics are designed to maximize the capillary action of fluids by sucking the water in our sweat away from the skin and towards the outside of the fabric where it can either evaporate or at least stop touching us. Even though the fabrics in our jerseys and bibs are heralded as being able to perform this task on their own, they are busy doing other things as well, and I find that using a layer dedicated to this purpose improves the effect greatly.
To be fair, though, the thought of wearing an undervest – or any additional thread of clothing for that matter – is far from inviting when kitting up in the middle of Summer. This is where DeFeet really shines with their multiple weights of undershirts, each targeted at a different temperature range. From the cooler months of September, through Winter and on into Spring, the Un-D-Shurt tank base layer is my go-to garment, keeping me dry but also adding a bit of warmth to stave off the cool air around Puget Sound. Once the mercury starts rising, however, I switch to the Un-D-Lite, which is much more lightweight and purpose-driven towards wicking rather than also insulating.
With both of these pieces, they are so stretchy, soft, comfortable, and good at keeping your skin dry, I never even notice I’m wearing them. I’d like to meet whomever figured out how to make this stuff; their brains must be so big, I bet you can spot it when you look in their ear.
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Good article, Frank. I've been wearing my Un-D-Wool for a while and love it. It's replaced my Descente base layers. Granted, I don't regularly wear a base layer unless the mercury drops below 50F...
@Chris
I agree; that is the config I wear for the most part all the way down to 0C, after which the LS Jersey comes out...But I prefer a layered approach to a ride over going with thick gear. The -5C to 0C window is very frustrating for this reason because I generally need the LS Jersey in that range, but its overkill with a gilet. That said, I'll throw the LS Jersey on sooner if the ride is a mellow one.
I also always dress to be cold the first 15 minutes of a ride; if I feel comfortable when leaving the house, I'm overdressed. Once the blood starts flowing, your temperature rises and you'll be shedding layers which you'll then carry around the rest of the ride.
@Cyclops
Hmmm, that sounded intriguing but I'm not totally convinced... not enough to shell out 60 quid on a base layer anyway.
Slightly concerned that they don't appear to have done any actual studies to back up this claim, just relying on what people say. (And also that their website confuses the word effect for affect, but that probably says more about me...)
Apart from that, the claimed effect on the affected areas is achieved when used with an unzipped jersey because it requires wind to cool it, which then has me wondering why it should be a base layer rather than a jersey. Particularly as they claim the material is more abrasion resistant than kevlar.
That means they could make a long-sleeve jersey which was cooler than anything else, won't tear and will prevent road-rash... but they haven't.
I'm perfectly willing to test one out for them. They can even stick a thermometer up my arse if they promise to get a professional to write their web copy.
@ChrisO
I hear you there. I've been testing out the UnD Ice here on Maui. It's a pretty constant 55-60% humidity and 20-25C in the shade. I'm not a dedicated user of base layers in hot weather like Frank is. In general, when climbing in the heat, one layer is hot enough, two seems crazy. This is when you really need to be cool, when climbing, when generating all the excess heat. When you are sweating you now have two wet layers of clothing on.
Once riding at speed or descending all that wet clothing does cool the body, but is it better than one light jersey layer? In the low humidity western USA it might work better.
I'm still testing the UnD Ice against my Craft and Santini italian stallion net base layer and will come up with a more definitive review. For now I remain unconvinced any base layer cools during climbing in humid weather.
@ChrisO the contention that there is an affected area necessarily infers that that there is at least some effect which does go some way to the argument as to their efficacy, no?
excellent and TIMELY advice..i am all over this
will buy and try, as its been a record year for heat out here, >100 for over 20 days, the record hottest year in the dust bowl years of 34 was 22 days...so, go figure...and we are just hitting august heat now
its been so hot, i didn't think i could dress for it, but perhaps i can
thanks
Every one seems to be overlooking the most important aspect of wearing a base layer under one's jersey: it just looks so f*ing pro!
@frank
@frank
On Frank's recommendation last winter I got a set of merino armskins and kneekers. They are indeed the business. I was good down to 0C, and only my hands were the real problem below that. DeFeet also makes some pretty nice oversock things. Will have to try their wool gloves, how low temp-wise would those who have used them say they go, and do they layer well?
@CanuckChuck
I'm with you and quite frankly a little shocked I didn't lead with that. Here's my original leading photo, but my neck looks just a bit too pasty and my right shoulder too washed out.
@DerHoggz
Because I can't resist the urge to post this pic of me on the Kapelmuur, you'll see I've got the DeFeet arm skins on as well as their overshoes and their thin wool gloves (even though I slipped my road gloves on over them.) I also have their thicker weight gloves but haven't really used them enough to know who cold they stay awesome to.