Field Tested: 45NRTH Sturmfist Gloves and Jaztronaut Insoles

45NRTH Collage 2

As you might expect with a name like 45NRTH, as in the 45th Parallel, this company knows a thing or two about cycling in extreme winter conditions. The Minneapolis-based brand was founded under the Quality Bicycle Products (QBP) umbrella back in 2011. 45NRTH’s initial product offerings were tires, but they’ve since branched out to offer products that keep your hands and feet warm and cozy as the mercury drops.

In order to fulfill this mission of providing warm goods for your hands and feet, 45NRTH is employing some space-age materials. Back in 2012, the company started using aerogel insulation in their Jaztronaut insoles. This aerogel offers the lowest thermal conductivity of any solid and the highest insulation value of any existing insulation. It’s the stuff NASA uses to protect astronauts in space.

Like other insulation materials, aerogel relies on air as an insulator. But, unlike your favorite puffy jacket, it doesn’t rely on loft to provide this insulation. Instead tiny nano-sized air bubbles in the aerogel create an insulating barrier between you and the cold. And, because the material is highly compression resistant, its ability to insulate does not diminish with pressure. So, it’s the perfect material to use in high-pressure locations like the soles of your feet and the palms of your hands.

This fall, 45NRTH announced two new glove offerings under the Sturmfist name; both employing a layer of the aerogel insulation on the palms and fingers to isolate your paws from cold handlebars.. The Sturmfist 5 (five fingers) target a temperature range of 15- to 35-degrees Fahrenheit, while the Sturmfist 4 (four fingers, with the pinky and ring finger paired) are aimed at the 0- to 15-degree range.

Sturmfist gloves utilize wind and water resistant Polartec NeoShell fabric for the outer shell material and Pittards water resistant goat leather for the grip surface. Both models also offer functionally awesome and luxuriously comfortable Merino wool lining material. A suede nose whip also graces the thumb of both gloves.

A note about sizing. The size 10 (XL) gloves we tested ran true to size so those with larger hands will find themselves wishing there was a XXL option, of which there is none. Try before you buy.


Sturmfist 5 Gloves – $100

by Justin Steiner

Though the Sturmfist 5 may use the same aerogel grip insulation as Sturmfist 4, its 100g Polartec Alpha insulation targets warmers temps. I’ve found 45NRTH’s temperature recommendations to be a good baseline. At 35-degrees, my hands were on the verge of sweating, but the Merino lining handles moisture incredibly well and the shell material is highly breathable. On the colder end of the spectrum, my hands weren’t toasty, but they weren’t freezing either and my hands tend to run cold. Adding a Merino wool liner glove helped with comfort in the 15- to 20-degree range for me. In these colder temps, the shell’s breathability sometimes left a chill in harsh winds or at high speeds on the road. But, the glove’s breathability is excellent for the slower-paced and higher exertion level of mountain biking, which keep the gloves from becoming a sweaty mess.

On the other hand (har, har!), the palm’s aerogel insulation was incredible. It isolated cold handlebars so well I could hardly believe it. No kidding, if the gloves were warm, the aerogel kind of felt like a heating pad on my way home from work.

Regardless of materials, gloves are only as good as their fit. I’m happy to report the Sturmfists were spot-on for me in size 10 (XL) and run true to a standard XL fit. The fingers were appropriately long for gripping handlebars without being short and binding or long and awkward. Considering the warmth of these gloves, the freedom of movement and dexterity is awesome.

Bottom line; these are the best gloves I’ve used. The quality materials, good fit and incredible dexterity come together in a top-shelf package. Sure, they aren’t cheap, but the price seems very fair to me considering the materials and comfort.


Sturmfist 4 Gloves – $130

by Jon Pratt

Like a lot of people, my hands tend to be one of the first things to get cold on those blustery winter rides. Not so with the Sturmfist 4. The zero- to 15-degree comfort rating is no joke. With 300g of Merino-lined Polartec insulation, and a removable 250g Merino wool glove liner, these mitts are toasty!

I’ve used a lot of winter gloves ranging from five fingers, to lobster claws, to full-on mittens. The four finger construction of the Sturmfist 4 feels just right. I was able to ride, shift and brake comfortably on multiple flat bar configurations and on the Shimano STI drops of my gravel/commuter bike. Obviously there is a little loss of sensation, but nothing as drastic as I would expect from such an insulating glove.

What I really appreciated was the ability to start a ride with both the liner and glove and as my body temperature rose, ditch the liner but still have a soft Merino lining to handle any residual sweat. The glove also extends well past your wrist and features a cinch cord that is functional without having to remove the glove to tighten or loosen it.

I wouldn’t recommend you rock the Sturmfist 4 on the warmer days of winter as I found my hands overheating once it broke through the 20-25 degree barrier, but for those bitter cold days these are definitely my glove of choice.

As an added bonus, the Merino glove liner, with its ribbed palm, makes a great cool weather glove and I find myself leaving them on while driving back and forth from the trailhead. The liners are available separately for $50.


Jaztronaut Insoles – $50

by Justin Steiner

Anyone who has ridden clipless pedals in cold temps is all too aware of the dreaded heatsink effect of the cleat and pedal. On really cold days you can feel the heat being pulled out of your foot. Remember the bit about compressibility? Well, most other insulating insoles I’ve tried simply lose their ability to insulated under pedaling or standing pressure, which leads to cold feet.

With the Jaztronauts, however, that cleat and pedal heat-sink impact was nearly eliminated. There was still a small sense of heat loss through the bottom on my foot, but it was far less than with any other insole I’ve used. I’d say it added at least 10- to 15-degrees of comfort to my Lake MX303 boots. Where my feet would begin to succomb to the cold around 20-degrees with the stock insoles, the Jaztronaut insoles kept me much more comfortable down into the low teens. Although I haven’t had a chance to try them down to zero, I’m certain I’ll be much more comfortable at that temp with the Jaztronaut insoles.

My only disappointment revolves around the lack of arch support. They offer virtually no arch support beyond that of your shoe. But, to be fair, the insulating insoles I replaced didn’t offer any arch support either. Regardless, the $50 upgrade to warmer feet is worth it to me.

The Jaztronaut insoles also come stock in 45NRTH’s Wolvhammer boots, which we reviewed back in 2013. Read the review here.


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