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These Dexshell Thermlite socks keep your feet completely dry, and so long as your shoes are roomy, they’re comfy too. Unfortunately, they really only delay the point at which your feet go numb, rather than stop it from happening. More of a problem is that, in some cases, they actually speed the chills up.

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The issue is their bulk – it’s kind of like wearing two pairs of regular winter socks at once. If you ride clipless and need everything tight, or your flat shoes already fit snugly with normal socks, they can constrict blood flow. We found that leads to painfully cold feet quicker than the same shoes with regular socks, despite our feet staying dry. 

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That bulk is a result of their design which, in isolation, seems ideal. The Porelle waterproof membrane has a soft liner made from a merino, acrylic and nylon mix, while on the outside your damp course is protected by abrasion-resistant nylon. You look like you’re wearing ordinary socks instead of, say, rubber gloves on your feet, which is nice. Given that it’s actually possible to inflate these socks like balloons, that’s a plus.

Despite the waterproofing and thickness, the extra bulk can constrict bloodflow and lead to colder feet

The Dexshells are well-made and durable, and there’s terry loop cushioning along the sole for comfort. It all adds up to reasonable if not exceptional warmth – the second syllable of ‘Thermlite’ is there for good reason – and considerable thickness.

The inside has a soft liner made from a merino, acrylic and nylon mix

Decent elastication means that, despite a boxy cut and slightly saggy look, they stay up without problem, and the height is good for staying above splashes or fords that would cover shoes or boots. Stand right in the river and not a drop gets through. The cold still does, though.

Despite the baggy fit, they stay put well

The Porelle is breathable but surrounded by all that material (and wet shoes) it struggles to deal with internal moisture. Inevitably your feet sweat, and the result is a slightly clammy feel. 

Basically, our best results were damp numb feet with these socks, versus soaking numb feet with regular ones. The Thermlites work perfectly in theory – they really are waterproof – but in practice the benefits are marginal. 

Though dry, your feet are still surrounded by freezing water - the outers are real sponges; I weighed the pair at 243g wet, against 100g dry. The wind remains far better at stealing heat from this water than the Thermlites are at keeping it in. 

They're waterproof, but act a bit like a sponge when wet and get much heavier

If you ride in roomy shoes and enjoy strong blood flow to your extremities, the DexShell Thermlites could work for you. Otherwise, you actually risk finding only marginal gains for a price 2-3 times that of quality thermal socks – or getting colder even quicker than normal.

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