Nubes, the Italian word for ‘clouds’, is an entirely appropriate name for this winter shoe from Treviso-based brand Sidi. You could wear a pair when the skies are clear, the sun is bright, and drifting snow lies deep on the gravel tracks, but you’ll probably end up with frozen tootsies. They’re very low on insulation, which doesn’t inspire confidence in the face of bitterly cold weather.
Instead, these are the shoes to reach for when the weather gods deliver a thick layer of cloud cover that traps a little winter heat. You know, the murky, temperate grey days that define the UK and, increasingly, much of North America too. Days that are miserably wet and cold, yet too warm for full-on winter booties – there’s nothing worse than starting a ride feeling toasty only to end up unpleasantly sweaty.
Despite its MTB-inspired name, the Sidi Nubes MTB/XC is a capable gravel shoe and works well for relaxed road rides too.
(Image credit: Simon Fellows)
Sidi does make a PrimaLoft-enhanced version, called the Algor, for proper cold-weather riding, which my colleague Tim Russon reviewed favourably. I’m reviewing the two-bolt SPD version of the Nubes here, but there’s also a three-bolt road version. Confusingly, Sidi and its UK distributor refer to the two-bolt shoe as both the Nubes MTB and Nubes XC, but they’re the same thing. Despite these ‘send it’-inspired names, they’re just as capable as a winter gravel shoe, as well as a marginally flexible road shoe.
Construction
The Sidi Nubes features a robust, waterproof TPU upper that extends well up the ankle.
(Image credit: Simon Fellows)
The latest Nubes MTB/XC shoes have a truly minimalist aesthetic. Until recently, the shoes were dominated by a large reflective brand logo on each heel, but thanks to a recent rebrand, there’s now just a subtle Sidi logo on the upper forefoot. While I never found the previous iteration offensive, the new design does look more premium. Are they winter shoes, boots or booties? Your choice – I’ll use the terms interchangeably.
The upper is a matt-textured thermoplastic polyurethane (TPU) laminate that’s branded ‘waterproof’ and feels suitably thick and durable to the touch. This is reinforced from the toecap to the heel cup with a thin yet tough rand. There’s very little stitching in evidence, with just two visible seams, one at the heel and the other just rear of the toecap. This near-seamless design should increase the likelihood that the upper remains weatherproof over the long term.
The TPU upper extends quite high over the ankle before being capped with a soft neoprene cuff. This contrasts with similarly priced rivals, such as Shimano’s MW502 and MW702 models, which have a more shoe-like upper bonded to a much taller neoprene cuff. Neither design is superior; both are a trade-off between comfort (flexibility) and weatherproofing.
The upper is sealed with a smooth-running, high-quality YKK waterproof zip that travels diagonally from forefoot to ankle. Once zipped up, the zip slider is enclosed at the top of the shoe by a hook-and-loop tab that also fastens the neoprene cuff.
The nylon/carbon sole is actually relatively stiff, despite its 5/12 rating. The rubberised lugs offer good grip and are effective at shedding mud.
(Image credit: Simon Fellows)
The sole is a nylon-carbon composite, with chunky rubberised lugs at the heel, forefoot, and toe. The toe section is replaceable and has fixings for a pair of studs should you need more grip on super slippery CX, XC, or gravel hike-a-bike sections. Sidi awards the sole 5/12 for stiffness, which is its lowest (most flexible) rating. However, take this rating with a pinch of salt – I can barely flex the sole in my hands, neither laterally nor torsionally, so it’s far from floppy.
Unzipping reveals a fabric, shoe-like internal structure that feels as if it could be pulled from the TPU outer, but it’s actually fixed firmly in place. The entire interior is lined with micro-fibre cloth, backed with what feels like slim foam; strictly speaking, these booties are insulated, but not substantially so. The included insoles are comfy enough but fairly basic. Sidi does not include arch support pad inserts, which is a shame.
The Nubes feature a simple speed-lace system, fastened with a sprung-loaded toggle. You won’t find any Boa or Sidi Tecno dials here, but that’s no great loss. The lace channel is, however, incredibly short; a detail my co-reviewer Tim also noticed. The tongue is soft and well-padded, preventing the lace cord from biting into the instep.
The YKK zip is excellent, and the tongue is well-padded, but note the shallow run of laces, which only extend up the forefoot.
(Image credit: Simon Fellows)
Sidi has attached two nylon webbing loop straps to the front and rear of the neoprene cuff to help pull the Nubes on. The rear strap, about 12mm wide, is printed with four small reflective triangles, an essential touch now that the large reflective logo has been removed. Just below the front strap is a decent-sized patch of reflective material, but otherwise the shoe is as stealthy as it gets. Not necessarily a good look on a winter shoe.
Cleat adjustment is good, with fore-and-aft adjustment via a standard sliding metal plate integrated within the cleat channel. Unlike Sidi’s of old, there’s plenty of scope to position cleats further back if you prefer to get well behind the pedal.
The Ride
Mind the gap! It is impossible to tighten the small neoprene cuff, which means that rain will leak directly into the boots during a downpour.
(Image credit: Jo Fellows)
The Nubes were my go-to shoes during December and January, months cursed with plenty of rain and a little snow but also blessed with the occasional fine day. Daytime temperatures here in the Cotswolds varied from about -2°C to 11°C (28.4°F to 51.8F), so quite a range. Overall, both months were characterised by mild, wet weather with above average rainfall. Perfect conditions for the Nubes.
I try to avoid riding in temperatures below 2°C (35.6°F) because my narrow local lanes, often shaded by high hedges and tree cover, become cruelly booby-trapped with numerous patches of black ice. This low limit is a perfect test for the Nubes; cold but not severe enough to worry a brass monkey.
The heel cups are well-protected, and the fabric pull tabs are a welcome feature. The lack of reflective detail on the rear of these shoes – just those tiny triangles – is a concern for a winter shoe.
(Image credit: Simon Fellows)
Pulling the boots on is easy thanks to the webbing loops and short lace channel; the latter provides a cavernous hole in which to slip a foot. Unfortunately, the limited run of laces only really secures the forefoot; they have very little purchase on the upper mid-foot. The zip closure does a great job of sealing the TPU outer shell, but that’s all it does; it doesn’t provide any tension, and neither does the hook-and-loop on the neoprene cuff. This means there’s no way to adjust the fit around the upper mid-foot and ankle; it is what it is.
There’s no way to adjust the fit around the upper mid-foot and ankle; it is what it is
When reviewing the closely related Sidi Algor, Tim Russon found this a real issue because the cuffs refused to seal around his ‘skinny ankles’ – his description, not mine. My ankles must be as slender as Tim’s because I’m also left with a sizeable gap around the top of the boot. This is not a problem when riding in fair weather on wet roads, when all the boots have to do is fend off spray. However, in downpours, rain runs directly into the boots. Layering the hem of my riding trousers or bib tights over the top of the shoe will ordinarily fix this problem – at least in light showers – but the oversized width of the neoprene cuff makes this hard to accomplish. What’s more, after a dozen pedal strokes, the hem inevitably rides up, breaking the makeshift seal. Trying to ease a tight latex gaiter over the top of the boot is more effective, but still feels precarious.
This isn’t necessarily a design fault; it’s a trade-off. Layering bibs over the top of a shoe like the Shimano MW502 is much easier because it’s essentially a winter shoe with an attached tall neoprene gaiter that fastens tightly around the ankle. However, the neoprene gaiter isn’t as robust or weatherproof as Sidi’s extended TPU upper. Both designs have their pros and cons – so, in the end, it comes down to personal choice. I don’t commute and can generally choose when I ride, which means most of my winter miles are on wet roads, ridden on rain-free days. If you commute or train hard in all weathers, you’ll probably want a shoe that’s less bulky over the ankle and seals more effectively at the cuff. Let’s be realistic, though – no shoe will ever be totally rain-proof.
The hook-and-loop closure on the short neoprene cuff doesn’t provide any tension, leaving a gap between the shoe and the ankle where water can ingress.
(Image credit: Simon Fellows)
Tim also commented that the lack of security at the midfoot promoted heel lift during sections of hike-a-bike. I haven’t found this to be an issue. If anything, the short lace run and loose cuff liberate my ankles, enabling a more natural gait, which is a good thing both on and off the bike.
In my experience, the Nubes are very comfortable to walk in, with just enough flex to allow the foot to roll naturally. The rubber lugs inspire confidence on damp babyheads, as well as on wet café floors, and are spaced generously enough to clear mud well. In the saddle, it rarely occurred to me that the soles felt a little less stiff than I’m used to with my super-stiff carbon-soled summer shoes. I can’t provide comparative power numbers (life’s too short!), but I can tell you that the soles on my giant size 48s are stiff enough to spread the load evenly across the entire metatarsal area. When wearing soft-soled shoes, I can easily feel where the small SPD pedal interfaces with the sole, which, on longer rides, can lead to a hotspot. That’s not the case with the Nubes. Talking of comfort, these shoes feature Sidi’s ‘Millennium’ last, which means they’re not only true to size – quite a departure for Sidi – but also wider in the forefoot and toe box. So, there’s no need to size up a full size, as you may have done in the past.
That said, even if you prefer your summer shoes on the tight side, I recommend choosing a slightly more relaxed fit for winter riding. Looser fit improves circulation, keeping your feet warmer. Everyone is different, but I found the Nubes perfectly serviceable at 2°C (35.6°C), so much so that I wouldn’t hesitate to wear them in conditions a few degrees cooler. At the other end of the scale, my feet were getting pretty warm while climbing hills at 7°C (44.6°F), but not uncomfortably so. I suspect they would have been unbearably hot in insulated boots.
Value and conclusions
The lack of insulation makes these boots ideal for relatively warm winters. Despite the thin layer of snow, this photograph was taken in 3°C (37.4°F).
(Image credit: Simon Fellows)
It’s easy to chase the numbers when choosing cycling gear, yet we should focus on the relevant use case. At a glance, ‘stiffer’ and ‘more insulated’ seem like positive attributes, but both qualities will work against us in the wrong conditions. In the UK and other temperate regions, there’s little call for super-warm shoes that will keep you toasty down to -5°C (23°F) and below. Most of us rarely see that kind of weather, and few of us will venture out in it on two wheels. I believe 2°C to 7°C (35.6°F to 44.6°F), give or take, is a much more realistic weather window for most riders, and a sweet spot for the Nubes.
Unless you’re racing, I see little need for ultra-stiff winter shoes. Gravel trails in January will be wetter, muddier and altogether more technical than in June, which means more hike-a-bike for most riders. You’re going to want a pair of shoes you can walk in.
Gravel trails in January will be wetter, muddier and altogether more technical than in June, which means more hike-a-bike for most riders.
On that note, I recommend SPDs for winter road rides too, unless performance is absolutely critical. Café stops tend to be more frequent in the colder months, as are mechanicals and punctures, so you’re likely to spend extended time on your feet. It’s dull, I know, but SPDs are just more practical in horrid conditions. SPD pedals are usually better built to withstand abuse, and their cleat/pedal interface clears mud and road grime more easily.
The Nubes cost £174/$219, which isn’t small change, but, sadly, these days it’s considered inexpensive for a winter shoe. Shimano’s entry-level, but very good MW502 shoes are in a similar ballpark at £149.99/$225. The Nubes feel a little more robust, but the MW502s seal better around the ankle.
Lake makes some of the best winter shoes on the market, but its most comparable shoe, the MX146 is considerably more expensive at £225/$. It’s a fine shoe though, with a much better closure system than the Nubes or the MW502.
The near-identical Sidi Algor is a good alternative to the Nubes if you are looking for an insulated winter shoe.
(Image credit: Andy Benson)
The obvious alternative is Sidi’s own Algor, which is near-identical but features Thinsulate insulation, which I’d argue limits its usefulness. To extend the Nubes’ operating range, you can always add warmer socks and a Thinsulate insole, but if this solution appeals to you, consider sizing up.
Finally, winter shoes are heavily discounted in the New Year, so you may be able to pick up a pair for as little as £100/$140, which is great value.
