Making An Insulated Running Shoe


By Joe Grant.

In the trail running off-season this winter, I’ve been riding my fat-bike a lot on dirt and snow. One of the challenges I’ve found with winter riding is keep my feet warm. Compared to running, my feet get very little stimulation on the bike so it’s hard to generate much heat to keep them from going numb. While there are a few clipless riding boots suitable for extreme cold temperatures, they are both expensive and have limited (specialized) use. While great for riding, clipless boots don’t allow for the versatility of a standard shoe, where I can ride to the trailhead, head up the mountain on foot and return home all while using the same pair of shoes and minimizing changes in gear. I found it near impossible to keep my feet at a manageable temperature without getting off the bike and running to warm them or opting for a full insulated boot (like a bulky pair of Sorels).


When running in the winter, I can usually get away with a Gore-Tex shoe since as long as I’m moving my feet stay warm. I’ve found this to be true even in extreme temperatures of -35F. However, on slightly more technical routes (that do not demand an actual climbing boot) I move slower, making it more difficult to keep my feet warm.

A route such as Kiener’s on Longs Peak in Colorado has a long approach from the trailhead, isn’t very technical, but is slow going in winter conditions. I don’t want to bring two pairs of shoes, one for the approach and one for the climb, so I get by in my Gore-Tex running shoes and cold feet. I knew there had to be a better solution to address both my needs for winter riding in extreme cold and run/climbing non-technical winter routes.

I first heard of a company called Forty Below, based in Washington state, while preparing for the Iditarod Trail Invitational a few years ago. They came recommended to me from runners and bikers who had done the race before. Forty Below makes highly insulated, neoprene, waterproof overboots designed to tackle extreme cold temperatures. Their primary focus is on mountaineering and arctic expeditions while also providing solutions for winter bikers and ski tourers. The main issue I had with the offerings on their site was that the overboots cover the entire shoe, including the sole, rendering the shoe tractionless unless used with crampons or other removable traction devices. This would not work for me for two reasons: in bad conditions with a lot of snow, I would be on and off the bike a lot alternating between pushing and riding, so I would need grip to hike and it also made the overboots useful only for riding if I were to use them on clipless riding shoes. I wanted something more versatile, so Joel at Forty Below proposed I get SuperGaiters to glue on to my shoes and build a shoe more specific to my demands. This turned out to be the ideal solution for me as I could combine the runability of my winter running shoes, with a warm, waterproof, insulated upper.

To build the insulated boot, I chose to use the Inov-8 Oroc 340 shoe for its aggressive, spiked outsole and warm, plush upper. I’ve run many winter miles in this shoe and knew it would be the ideal candidate for this type of project. In choosing a shoe, I would suggest picking one with aggressive traction for good purchase in snow and possibly with metal dobs such as the Inov-8 Oroc models, Icebug shoes or Salomon Spike and SnowCross. Alternatively, you could add screws to the sole of your shoe, but since this shoe will become a dedicated winter boot, I find it best to go with a spiked option. In most conditions, the metal studded shoes make microspikes unnecessary, therefore eliminating the need for extra gear.

I size up a half-size (sometimes even a full size depending on the model) for winter footwear to accommodate thicker socks and allow for better blood circulation.

The gluing process is fairly straight forward and well explained on the Forty Below website. After trimming the gaiter to fit the edges of the shoe exactly, I used the recommended Barge Cement glue to attach it to the shoe. This process is a bit tedious, applying and reapplying the glue over several days, giving it adequate time to dry.

After the gaiter is glued on, the next step is applying Plasti Dip around the exposed edges of the neoprene that come into contact with the sole of the shoe to create a rubberized rand to help with wear and tear. I had never used Plasti Dip before and while it’s nasty stuff, using it to repair or reinforce weak points on shoes was a minor revelation. Rocks or snowshoe straps will often create abrasion on my shoes that I can now easily fix using a layer of Plasti Dip and reapply as needed. It also gives the gaiter as nice finish and bond to the sole of the shoe.

The finished product might look a little bulky, but the shoe maintains all of it’s running properties, while benefiting from waterproofness and insulation. The added thickness of the neoprene on top of the foot makes the use of crampons more comfortable on a flexible shoe. The SuperGaiter greatly expands the applications of a standard running shoe for high altitude running (such as Russian Skyrunning races) and on non-technical winter peaks.

So far, it hasn’t been cold enough in Colorado for me to really give feedback on the temperature ranges I can stay comfortable in with the boot, but they have withstood a few hikes at -10F without trouble.

The down side to the Forty Below SuperGaiter is that it is not cheap, so I would only suggest getting a pair if, like me, you have a lot of use for this type of shoe. Other options to consider are using Forty Below’s cheaper gaiters (such as the Light Energy Shorty Overboots or the Simple Slipper Overboots) and cutting the sole out before gluing. Winter surf or fly fishing booties could also be cut up and customized to fit on shoes, but wouldn’t have the benefits of the wide velcro opening to get in and out of the shoe easily.

To sum up, if you’re looking for an option to weatherize your running footwear for extremely cold environments, consider giving the Forty Below SuperGaiter a try.


By Joe Grant:


6 thoughts on “Making An Insulated Running Shoe

  1. No, they aren’t particularly heavy. I haven’t weighed them, but they feel and run like a running shoe despite looking bulky. The flexibility of the shoe is unchanged.

  2. Hi Joe! Just back from Rovaniemi, Finnish Finland where I ran the Rovaniemi 300k. 4 days in – 20 to – 27 degrees! I used the Inov8 X-talon 212 with the 40 below gaiters. It worked wonders to protect my feet from the cold. However, they didn’t last. The gaiters started to un-glue on the sides on the 3rd day of intense use…. I think the pressure to make the gaiters held on the sides is too high on a small size like mine. I have to find a way to improve this as it’s an amazingly comfortable solution. I can’t imagine myself hiking in heavier boots. I will contact 40 Below and see whether they have any tips or solutions. Cheers!

    1. Hi Rachel! Great job on the Rovaniemi race! Wow! Sounds really tough and that’s some serious cold weather. I’ve had similar durability issues on running shoes because on the shoe flex. Even though the glue bond is strong, the repeated flex of running breaks it down over time. There are two alternatives: replace the glue-on gaiter from 40 below with one of their regular overboots. You apply the same method to glue them to your shoes, but cut strips out of the bottom to let the tread through. For example with the 212’s you could leave a pretty large strip through the arch that connects both side of the overboot and will just keep everything in place. You’ll probably still have some areas that come unglued, but won’t risk completely losing the gaiter. Another option is to invest is a fully gaitered shoe such as the Salomon XA-Alpine, Scarpa Atom Evo or LaSportiva Crossover. The advantage is the shoe is ready to go without needing any extra work. The disadvantage is the tread isn’t as aggressive as on the 212’s and the insulation is more minimal. If you get any of these shoes in a full size bigger, you won’t limit circulation, can wear thicker socks and that might just be enough to keep your feet warm in those conditions. When I ran the ITI 350, I used an inov-8 roclite 280 (high top) with regular mountaineering gaiters. My feet were never cold even in -35 (I did bring 4 extra pairs of dry socks to ensure my feet stayed dry and warm and I could change in an emergency). Hopefully, 40 below will help you out and you can find a solution that works! Cheers!

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