Castelli eschew the insulation-plus-shell construction of conventional winter cycling gloves for their Diluvio gloves, instead using a full neoprene shell similar to those used in wetsuits.
Stitches are solely external, interior seams are welded, nylon linings inside and out provide some abrasion resistance for cycling use, and the palm and finger area is covered in tiny rubber dots for grip.
Despite the minimal 3mm-thick material, the Diluvios are amazingly warm even in just-below-freezing temperatures – but only if you wear them properly. In diving, wetsuits are only warm because the body can maintain a heated layer of moisture right next to the skin and it's no different here.
When we donned the Diluvios right before heading out on a cold day, no moisture built up and our hands stayed dry but they invariably froze. But if we put them on while our hands were still warm, they stayed that way and quickly thawed out again if we briefly had to pull the gloves off mid-ride for whatever reason.
The thin material and skintight fit makes for pretty decent bar feel – so much so that we even managed to type part of this review while wearing them!
The key to the Diluvios' impressive warmth is also the source for our biggest complaint, though. Even Castelli readily admit that the neoprene is wholly unbreathable, so while your hands stay warm, they get clammy in a hurry. This also makes them very slow to dry after washing, since machine drying is a definite no-no.
Unfortunately, buyers shouldn't consider the Diluvio to be a lifetime prospect. The keen white scorpion logos have already started to crack on our test gloves after just a few weeks of use, some of the rubber dots on the palm have already come off, and there's no snot wipe.
Like all neoprene, the tiny bubbles infused into the rubber that lend the material its convenient properties will also eventually outgas after a couple of years.
Okay, so the Diluvios won't last forever and your hands get pretty sweaty in them – but they're great on race day and man, are they toasty.