It is probably safe to say that most cyclists are not strangers to arm warmers. But what of their hot-weather cousins, the arm coolers? Those are a rarer beast. Worn with short sleeve jerseys, arm coolers are lightweight sleeves designed to protect from heat and sun. In intensely hot weather, wearing them is supposed to keep you cooler than cycling with bare arms or in a long sleeve jersey. So, do arm coolers work? Having tried the versions from DeFeet and Rapha, I believe they do. Here is more about them.
Sun Protection: SPF 50
Fabric: olefin/nylon/spandex blend
Country of Manufacture: USA
The DeFeet ArmSkins Ice are designed for both sun protection and abrasion protection. They are made of a rather thick, densely woven fabric that evokes medical compression wear. The texture has a striking silky sheen to it when new, though it subdues after some use.
The ArmSkins Ice come in two sizes: S/M and L/XL. I fit the former. Pulling these on for the first time, the fabric is so dense it feels almost reluctant to stretch. But once in place, having these on is comfortable and non-constricting. For me the length is sufficient to overlap with cycling gloves.
The ArmSkins are constructed as seamless tubes. To stay up, they use a roll-top design instead of elastic or silicone grippers. The roll tops work fairly well to keep the sleeves in place, though on long rides I do adjust them occasionally. Personally I like the roll-top: Unlike silicone grippers - it does not pinch, squeeze or chafe the skin on my upper arms, especially on long rides in hot weather.
Developed for temperatures over 80F and well into the 100s, the fabric of the ArmSkins Ice is described as being activated by air-flow, the "densely packed fiber molecules" causing "rapid heat exchange. If I understand correctly, the claim is that the material does not just protect the skin from outside heat, but actually sucks and expels heat from the body. According to DeFeet, the dense weave also offers abrasion protection in case of a fall or scrape - more so than a leather jacket. A technical discussion in this review describes how all of this works in greater detail.
In use, the ArmSkins Ice feel cool to the touch, even in intense heat and sunshine. But moreover, once in a while I get the sensation of cold flashes along my arms. This happens in the absence of any breeze, but it does happen more when I ride fast, which probably means it is caused by increased air flow. To feel a chill on my arms in 90F heat and direct sun is quite something. I cannot comment on the abrasion protection, but the cooling properties of this garment are impressive. Wearing the DeFeet ArmSkins Ice feels like having an air conditioning system wrapped around my arms.
Sun Protection: SPF 50
Fabric: polyester/elastane blend
Country of Manufacture: Turkey
The Rapha Arm Screens are made of a stocking-thin fabric. They weigh next to nothing and, crumpled-up, will easily fit into the meagerest of jersey pockets. Pulling them on, the material hardly registers between the fingertips.
The Arm Screens are shaped, with bonded seams running along the inside of the arm and articulated elbows. Reflective logos sit just above the wrists.
The sizing (XS-L) is similar to Rapha's arm warmers - which is to say, they run small. However, they are also very stretchy, so there is some leeway. I am a US woman's size 4 with arms of average thickness and below-average muscle tone. I can fit into the Small, but the Medium feels more comfortable - with no sausaging effects and with length to spare. For those unsure about their size, I would suggest erring on the larger side: The longer length will ensure there is no gap between the Screens and your cycling gloves.
The Screens stay up with the help of elasticised bands, which are as thin as the rest of the fabric. There is no silicone gripper and, compared to other designs, the hold is gentle - not pinching or squeezing the skin at the top. But the bands have worked well for me so far. For example, they kept the Arm Screens in place for over 15 hours straight on a recent long ride. The fabric feels delicate, though after some weeks of rough handling I have not snagged it yet.
The "proprietary stretch Swiss fabric" used to make these is a polyester/elastane blend with "coldblack technology to keep the fabric cool against the skin." It has also been subjected to "anti-microbial/anti-bacterial treatment." Beyond this, Rapha does not elaborate. But whatever the technology is, it works. Wearing the Arm Screens pretty much feels like not wearing anything at all. I do not notice them on, other than that my arms feel cooler. Compared to riding bare-armed, I do not feel the heat or the burn of the sun's rays against my skin. Perspiration does not gather on any parts of my arms and removing these after a long ride, they are dry. The Rapha Arm Screens protect from sun and heat, while feeling weightless and comfortable on all-day rides.
Identical in price point and SPF rating, the arm coolers from DeFeet and Rapha offer different technologies to deal with intense summer weather. A benefit specific to the DeFeet ArmSkins ICE is their added abrasion protection. A benefit specific to the Rapha Arm Screens is their weightlessness. Perhaps an obvious caveat - but both tend to get dirty in use, so do not expect them to remain bright-white for long.