Sidi HiemX Gore-Tex shoes- Could this winter boot actually be the ideal UK multi-season option?

Sidi is one of the best-known shoe brands out there, and there was a time when it was the only footwear to be seen in. Times change, however and in recent years it has started to be overtaken by others, in part due to its polarising narrow fit

This is now changing, with a new last in use and the Hiemx is part of this 'comeback'. We have previously tested the Sidi Nix, a similar shoe designed for road use in winter, but could the mtb version make for the ideal all-season gravel boot?

Construction

The first thing you notice is the styling; it's far from the usual Sidi formula and features a mix of subtle, earthy green tones and a very modern-looking matte finish. They are ankle-high boots and feature a flap covering the tongue and retention system section, made from robust rip-stop material, which is joined to an ankle cover. All of this is designed to keep mud and water out of the shoe. I had the black and green olive colourway on test, though they come in three other colour options.

The upper combines a mix of reinforced textile, TPU, and a Gore-Tex ePE membrane. The membrane is designed to be both waterproof and breathable, and it’s paired with a soft, fleece-lined Gore-Tex liner to help keep your feet warm. Much like a waterproof walking boot, there are no gaps between the tongue and the rest of the shoe, though it is a flexible and reasonably soft material, so it shouldn't bunch up and cause discomfort when you tighten up the retention dial.

Regarding retention, the Hiemx utilises the Italian brand's long-established high-density dial System with Dyneema cables, which provides a precise and secure closure. It’s easy to adjust the fit, and the dials hold tight even when the shoes are muddy or wet, and though it looks similar to the ubiquitous Boa system, it works in a slightly different way; you turn the dial to tighten, and press the two side buttons to release. There's no way to make minor adjustments with the release mechanism, so it's a case of releasing the pressure and retightening as required, which is easy to do, even in full finger gloves, thanks to the little flip panel, which makes closure easy to do on the move.

The X2NC sole blends nylon and glass fibre for stiffness, which Sidi gives an arbitrary rating of seven. I say arbitrary, as there's no standard for shoes, but it provides a good indication of where it fits in a range that goes up to 12. The outsole is much grippier than older race-style Sidi mtb shoes, with a soft-feeling material and replaceable toe caps. The boot also features a reinforced toe section, making for a robust boot that should stand up to plenty of off-road hammer.

Weight, fit and sizing

My shoes weighed in at 482g each in size 44, making them mid-weight for a winter mtb shoe and lighter than the Sidi Algor, which has more insulation and is designed for colder temperatures. To be honest, though, weight isn't one of the key criteria for me in a boot designed for dealing with the elements; still, the fact that they aren't super heavy does make them a more versatile option compared to heavier-duty winter boots.

Sizing is an area that Sidi has often been criticised for in the past, offering shoes in long, traditional Italian-style narrow lasts, which were efficient and very supportive, but only if, like Cinderella, you could get them on. The Hiemx features its latest Millennium fit, which means they are wider with a roomier toe box. I found them to fit well with no unwanted movement or rubbing, and the fleecy lining gives the boot a snug feeling. Although there is only one closure, it closes up nicely and provides ample support, not quite as locked-in feeling as a pure race shoe, but much better than other winter boots I've used.

Sidi offers the Hiemx in sizes ranging from 40 to 48, but not in half sizes, unlike its racier offerings or different widths, such as those from brands like Lake. They came up true to size, too. I'm generally a 44 in most brands, and that was the case here as well. The insoles were well-shaped for me, with a medium arch height that suits my feet. However, if you have particularly flat feet or high arches, you may want to invest in something more tailored to your specific needs.

The ride

When first putting the shoes on, they feel a little stiff, but they soften up nicely after a few rides. They aren't as easy to get on as a normal shoe; the higher ankle makes it a touch more difficult, but not enough to be a problem and pulling on the loop at the back really helps. In fact, I'd take the extra second or so to get them on if that means warm, dry feet anytime.

The retention system does a good job of closing the boot around your foot, creating a snug fit. On the first few rides, I was aware of slight bunching on the tongue section, but this eased off after time. The velcro cover does a good job of keeping mud and water out, and tightens down well, though it's worth making sure you press the velcro closure down along the length of the flap to ensure it stays in place. The high ankle is pliable and comfortable, and fits ok. The Velcro flap tightens it up a little when you close the main flap, but I would prefer it to tighten a bit more to achieve a closer fit and keep water out.

Out on the trails, the HiemX is instantly comfortable. The fit is secure and supportive without feeling overly tight, and the fleece-lined upper keeps feet warm up to around 12-14°C, making it ideal for autumn, winter, and early spring UK rides. The shoes handle damp or frosty conditions well, though, as you would expect, they are less suited to hot summer days.

The combination of a stiff sole and snug fit gives a confident pedal feel, with efficient power transfer and minimal foot movement. Over nine months of testing in all sorts of weather and trail conditions, I found them to be durable and comfortable across a surprising range of temperatures and weather.

It's the versatility of the Hiemx that I really like, especially for early morning or evening rides, or for when the trails are a bit damp. The extra height on the ankle and the Gore-Tex lining keep most of the water out (Some will always come down your shins in a downpour and into the shoe), and for splashing through puddles and general off-road riding, they keep you warm and drier than you would be in a racier shoe. They feel efficient and not too heavy either, which means they feel much like a regular shoe on the bike, too.

Value and Conclusion

At £299.99 / $344.99, the Sidi HiemX MTB shoes are priced at a premium, but the quality of build and the versatility of performance justify the cost for me. They offer a great fit, durability, and comfort across a broad range of temperatures, making them a solid choice for UK riders who encounter varying weather conditions. I've found that I use them a lot more than I expected, and for much more of the year than a really heavy-duty winter boot.

Overall, the Sidi HiemX shoes are ideal for riding in cooler to mild temperatures and will comfortably see you through most of the year’s riding, excluding the hottest summer days. If you're the sort of rider who likes to get off-road, whatever the weather, year-round, then these could be the shoes you didn't know you needed.