The Sidi Hiemx shoe is a great off-road winter boot in many respects but it’s let down by an annoying tension dial and has what could be seen as a major design flaw, both of which would have been easily sorted early in the design stages by someone who rides in the colder and wetter seasons. This makes the premium price a little hard to justify and leads to casual browsing of other options.
The Hiemx is part of Sidi’s new series of winter shoes for both road and dirt and is the most expensive of the off road options. Next down pricewise is the Glacies which is similar to the Hiemx but uses a quick lace closure system under the flap rather than a ratchet. Then there’s the Algor which is a fully enclosed winter boot and finally the Nubes XC which is its slightly cheaper version. The Hiemx comes in four colours and it’s the Angel Delight flashback Peach we have here, plain black, olive and one with a little bit of hi-viz yellow are also available.
The Hiemx is described as being trusted by XC elite riders and engineered for extreme cold trails and for a winter shoe it’s definitely light enough and sleek enough and stiff enough for efficient cross country duties and doesn’t feel like you’re dragging around a hiking boot if you’re getting some miles in through the muck. Fit is roomy, which will come as a welcome surprise to old-school Sidi fans who might be more used to their tight and narrow Italian disco slipper squeeze. The Hiemx conforms to Sidi’s Millennium fit and what that means is essentially more room for your feet. The inside space of the Hiemx was wonderfully spacious and comfortable, even across multi hour rides, particularly handy in a winter boot where tight shoes can restrict circulation and promote chilly toes, sizing was spot on and there was no need to size up for potential Sidi-ness or to fit a thicker winter sock in the shoe.
Hiemx tightening is done by just the one dial using Sidi’s own system that’s been around since long long before the BOA ratchet took over the cycling world. It’s generally a good system in that it sits flush to the shoe so unintended releases by exuberant foliage and bouncing off things that can occur with other systems just don’t happen. The downsides are that rather than grabbing and twisting a large protruding dial like a BOA system the Sidi tensioners requires you to flip up a half-moon shaped tab and rotate it to do any shoe tightening and whilst it might be fine in the summer it’s a fumbling process to use with fat fingered winter gloves. Added to this is dials on both the left and right shoes tighten clockwise which is a minor annoyance if you’re used to a BOA dial that rotates towards the front to tension on both shoes. I’m no ergonomics expert but tightening the left shoe felt awkward and counter-intuitive, and I’m left-handed.
Tension release is performed by two small tabs either side of the dial and you can micro release by pushing just one of them in, but which one that is depends on how many tension clicks you’ve done, sometimes it’s the front one, sometimes it’s the rear, which can be a fiddle. Lift that half-moon tab and push those tabs together and you’ll dump all the tension for when you want to remove the shoe, and there is a positive to that gappy ankle in that the Hiemx is easy to get on and off.
As anyone whose used Sidi shoes off-road before will tell you that the tension dial can fall prey to undergrowth getting wedged in it and sticking the mechanism solid making sure you’re staying in the shoe for a longer than you might like until you can poke at it with something sharp and pointy. Similarly and more seasonally they can suffer with dirt ingestion and get clunky and crunchy with grime and grit, which can make them reluctant to release and spoil the end of a ride, a thorough wash or squirt with penetrating oil will clear them out.
The Dyneema tension cable criss-crosses the foot and stops mid way down the shoe so if you like an extra tensioning device towards the toes you’re out of luck. The upper of the Hiemx is flexible yet tough so that single ratcheting dial has a lot of work to do and another one lower down might please some and spread the load. The whole tongue area and tensioning wire is covered and protected by a durable Ripstop flap that Velcros to the side of the shoe and it does a very good job of keeping water out of that part of the shoe and fending off scratchy foliage.
Whilst I’m mithering about the tension dial, its placement is too close to the Ripstop flap. That flap is pretty thick and sits proud of the shoe meaning the tension dial sits in its shadow and it can be awkward to get to and adjust, especially with thick gloves, doubly so if the flip out tab is resting in the top half of its rotation as it’s hard to get fingers in there to find the ratchet. I’m no stranger to the Sidi tensioning system having had them on a history of road and off-road shoes and this all felt unnecessarily fiddly.
Your foot is held in place within the shoe by the Firmor lateral support band, which stabilises the ankle, and an anatomic heel cup keeps your foot well supported with no heel lift when pedalling hard and it keeps things in place even when walking.
The Hiemx has a nylon and carbon fibre X2NC sole, giving it stiffness index of 7, putting it towards the floppier end of Sidi’s random numbers stiffness chart that ranges from 5 to 12.
This makes them solid rather than outrageously stiff to ride in, which is fine as you don’t always want the most rigid off-road shoe available, especially in winter, where conditions might have you off the bike and walking more often. They’re certainly stiff enough for multi-hour rides without any discomfort from flex, and they’re merely a bit clumpy to walk in rather than impossibly rigid. The sole has a good amount of chunky grip on it, making it a reassuring shoe to walk in, although the tread at the front around the cleat isn’t spaced out so can clog with claggy mud. There’s an extra layer of grip on the mid-foot for a bit of protection and grip during fluffed clip-ins, and there’s a replaceable toe section that accepts a pair of threaded studs should you feel the need for added traction up front. That ability to get spares might come in useful as one of the yellow toe grips has disappeared somewhere.
The whole toe area is reinforced and after a litany of stumbles, kicks, roots and trudges, is showing minimal signs of wear.
The upper body of the Hiemx is made from a sturdy TPU (that’s Thermoplastic Polyurethane), reinforced with a new Gore-Tex ePE eco-friendly membrane, which claims to be weather and water resistant, and windproof. It does do a very very effective job, puddle water can be whooshed through to gleefully watch it run off the shoe without any impact and cow mudded gates can be trudged across without any fear of the outside getting in and this impervious layer combined with the fluffy insides makes the Hiemx a nice place to be. The whole upper is free from much fancy detailing or inserts, the tiny holes seemed to do their job of keeping the shoe breathable without letting any moisture in, so they’re a doddle to clean after a muddy ride, they dry quickly too.
The entire insides of the shoe are lined with a soft, temperature-regulating Gore-Tex fleece, and it’s lovely. Comfortable and cosseting to the foot it keeps things toasty down there in the extremities, and it kept things that way for long rides across single-figure tundra. Toes did get to chill a bit towards the end of the day, though, especially if it had been a frequently puddle punctuated ride.
And now we come to what is Sidi Hiemx’s Achilles heel, literally, and that is the large gappy ankle that lets mud, puddlesplash, rain and everything else in. Whilst comfortably padded and with a pull tab on the rear it’s a firm and wide-mouthed structure that leaves a lot of room around the ankle, allowing quick and easy access to the inside of the shoe for anything winter wants to luzz in. Go through a splashy puddle and while the body of the shoe will happily shrug it off anything that washes above that slops straight into the top of the shoe, the girth of your ankle will affect how much gap there is (I am all sinew and bone down there) but the top of the shoe is still poorly protected against the elements.
There’s always an issue with a winter boot in that no matter how resistant the main body of the shoe is wet and mud from above will eventually get in via any ankle gaps and seep in via sock, tight and leg and many off-road winter boots do their best to get round this with an integral gator of some sort, but the Hiemx is an open invite. Anything that hits above the shoe happily flows in or soaks a sock and seeps into the shoe, both making that nice fluffy fleece lining damp and cold, negating its thermal effectives and totally undermining the water resistance of the Goretex body of the shoe. You could buy an aftermarket cuff like the Grip Grab Cycling Gaitor to cover up this exposure but that’s a bit much when you’ve already put down £300 on the Hiemx. Ho hum.
Sidi Hiemx – Verdict
Front row competition in the cross-country winter shoe field alongside the Hiemx comes from the likes of the perennial, classic and many varied Northwave Celcius shoe that benefits from a cable that criss-crosses further down the boot and has an integrated neoprene collar that does a great job of keeping muck and rubble out. The more recent Terra Artica GTX (https://road.cc/offroad/content/review/shoes/fizik-terra-artica-gtx-winter-shoes-review-11453) is Fizik’s offering which has a fleece lining and an ankle cuff that’s secured to the leg with a Velcro strap but Matt wasn’t impressed with them feeling they weren’t that warm, were too narrow and suffered from water down the ankle despite that cuff. The Endura MT500 Burner Clipless Waterproof Shoe are a little less XC and the orange colour is… challenging (black is also available), but they’re from a Scottish company, so they should know how to make a winter MTB shoe, right? While it doesn’t offer any insulation and uses a speed lace rather than a tensioning dial, Patrick was very impressed by their waterproof capabilities, helped by the wrap-around neoprene double wrap ankle gaiter.
While the action and placement of the Sidi tensioning dial was a minor annoyance for any mid-ride shoe tightening, the lack of any winter protection around the ankle and significant gaps on the Hiemx seem a major design error. Oddly, the cheaper Algor or Nubes XC have better ankle protection, but are secured by a Quicklace hidden underneath a weatherproof zip, so tension might not be as tight as you like, and on-the-fly adjustment isn’t possible. The extended cuff that appears on their Nix winter road shoe could be a very welcome addition if anyone at Sidi is listening.
There’s a lot to like about the Sidi Hiemx as a winter boot, it’s light enough for XC work and despite being towards the lower end of Sidi’s stiff scale didn’t feel unecessarily flexy, it’s roomy and comfy thanks to the Millennium last and warm courtesy of the fluffy insides and the main body of the shoe is very effective at shrugging off weather, wet, dirt, stones and undergrowth. Unfortunately all of this is let down by a tension dial that’s fiddly, especially in thick gloves and more importantly by a gaping ankle hole that likes to welcome winter in.
All the deals displayed on our review pages are pulled from a constantly updating database feed of the best affiliate deals available. The criteria for deciding on what are the best deals is who is offering the lowest, delivered price. In most cases we will be showing the very best deal available online, but sometimes you may be able to find an item cheaper. If you can please feel free to post a link in the comments box below. To find out more about affiliate links on road.cc click here.
