I've done a study!! Sort of. Maybe not quite up to drug trial standards, but still, I used a control (my left hand) and the test object (the right). And the results are in.
From top to right, here they are:
First point to make, is that glove sizing seems bizarre. I definitely do not have "large" hands, at least not for a man. I used to work in construction, some of our labourers had hands almost as big as their shovels - that's what I'd call large. These days I teach guitar to teenagers. Some of the 14 year old girls have hands bigger than mine. But I still ended up getting "large" gloves. Maybe the sizing is across all ages, and includes children's gloves?
So if you're shopping for gloves, try them them on if possible, or buy from somewhere with a decent returns policy.
The first set of "gloves" are actually silk liners, as recommended here. They made the gloves
a little warmer, in every case. But not by a huge amount. What was noticeable was how much bulk they added, considering they are very thin. If you're going to use liners,
on a bike, it's the equivalent of going down a size (I had two pairs, size 8 and 9, of the Skytec gloves).
As well as "subjective" testing - "do my hands feel warm/cool/cold/freezing/I can't tell I've lost all feeling" - there was some "objective" testing. Also known as taking the gloves off the moment I got back in the house and asking my wife to tell which was warmer.
2nd set are some
Altura gloves. I don't think they're really intended as cold weather gloves, just maybe "cool" weather. Right one with silk liner, left one without, my right hand felt a bit warmer, but still uncomfortable. Around 3/4/5 degrees centrigrade.
3rd set are those Carnac crab things. These are "medium", but are still a bit tight. They go on, but don't leave me with as much dexterity as I'd like. And I'm not a fan of the two fingers together arrangement. They were nowhere near as warm as I'd hoped. A little warmer than the Altura+liner, but not much. Because they are a bit small, I never tested with a liner.
4th set are Skytec Argon builders gloves, as recommended here. The warmest so far, and a little warmer if there was a liner in one. But still not as good as I'd hoped. I bought two pairs, I'll return one and keep the other for actual DIY, gardening etc.
5th set are Decathalon ski gloves. As far as I could work out from the chart in the shop, these are the lowest temperature rated (down to -11 deg C). There are these:
https://www.decathlon.co.uk/p/adult-warm-ski-gloves-gl500-green/347696/c219c382m8937395
They were warming than any of the others, and the liner seemed to make a bigger difference than it did with any of the others. To be clear, I tried them against the Alturas, and the Skytecs, with and without liners. I also tested them having the Decathalons on both hands, but a liner only on the right hand. I wonder whether there's a perception thing going on. That if one hand is comfortable, but the other is cold, you feel the difference more. Whereas if both hands are cold, you don't feel the difference as much. Anyway, the liners seemed to make a bigger difference here.
So, that's the results.
Couple of considerations:
This was on a bike with drop bars and STI shifters (Ultegra 9 speed triple). So dexterity matters more than it might on a flat bar bike. I could handle the controls fine with all, but didn't really like the Carnacs.
Temperature was in the low single figures, might even have been just above freezing where I was cycling.
The ski and builders gloves don't have gel pads or similar on the palms. I could feel the difference, and on a long ride might get problems. But on these 14 miles rides it was fine. Worth pointing out that I don't "need" gel as much as some people might. My position is fairly upright, and I've put a huge amount of work into setting up the bike for comfort (saddle lower than bars, short stem, Nitto noodle bars, long lay back seat-post, etc. etc.). If you rely heavily on padded gloves, bear that in mind.
