Fourth Season Skills is a series of articles about riding bicycles in the winter. Topics will include everything you need to know about equipment choices, clothing, riding skills, and how to stay warm. Even in the harshest temperatures. I will draw on my many years of experience living and cycling in Northern Minnesota. I have commuted by bike in all four seasons for 12 years. I am a veteran of the Arrowhead 135, one of the hardest winter races in the world. I am a winter camper and winter camping instructor.

Feet were definitely my weak spot when I first started to ride in colder weather. Colder being defined as anything below the freezing mark. I can’t count how many times I came home with toes that were numb. Then enduring the painful process of bringing warmth and feeling back to those toes. I mean real pain. Laying on my bed trying not to scream, whimper or cry as warmth returned to my toes. Anyone that has experienced this pain knows what I’m talking about.

I spent the year of 2006 training and preparing for my first attempt at riding the Arrowhead Ultra 135. A winter adventure race known for it’s brutally cold temperatures. I knew I had to figure out the feet thing before I could even think about pulling up to the start line. Even though it was only 10 years ago, a lot has changed since then. In 2006 there was very little information available on-line about riding a bicycle in winter. The first commercially available fatbike, the Surly Pugsley, had only been on the market for a year. Up until then, winter biking meant riding a road bike in temps in the 30’s and 40’s Fahrenheit. The bicycle industry made “winter gear” and clothing. Most of it was worthless for keeping you warm in anything colder then the 20’s Fahrenheit. The common response for keeping feet warm was to buy shoe covers for your summer biking shoes. In reality, these lowered the temperature your feet would stay warm in by, at most, ten or fifteen degrees. I needed to prepare for temps as low as -30degF and be able to keep my feet warm for 24-35 hours.

I finally sought out information posted on the internet from people who had ridden in those temps in similar events similar to the AH135. People like Mike Curiak and Dave Gray. Dave was the man behind the design of the Pugsley at Surly. He had ridden the AH135.

There is one thing I learned from this investigation. It can be summed up with two words. Remember these two words: Air Space.

You must create an environment for your feet to stay warm in. This is done largely by giving your toes airspace in whatever type of footwear you decide to wear. It can be a pair of hiking boots you get on clearance for $50 like I did. Or it can be a pair of 45NRTH Wolfgar’s for $450. 45NRTH may not appreciate me writing this, but either option will work just as well at -30degF if you fit them properly. If you have the means to buy the Wolfgar’s they are a great option.

Let’s back up a bit. The problem with using your summer shoes for winter riding is the fit. Presumably most people buy a summer bicycling shoe, whether it be a cycling specific shoe or “tennis shoe”, to fit snuggly with a thin to medium thickness sock. When temperatures drop, the prevailing thought is to layer two socks or wear a thicker sock to keep your feet warm. There are two problems with this.

1. The whole reason for layering or wearing a thicker sock is to provide more insulation. What provides that insulation is the loft of the sock. Or you could think of it as the fluffiness of the thicker sock. It’s the loft that holds the warmth next to your skin. However, if you cram your foot with that sock into a shoe that already fits snug, what happens to all the warmth holding loft? It gets compressed. Once compressed it loses it’s loft and it’s warmth holding properties. It no longer insulates.
2. When you cram your foot with thicker socks into an already snug shoe the fit is much tighter and ends up restricting blood flow to your foot. Less blood flow = colder feet.

I can’t remember how many times I’ve heard cyclist say they can’t understand why their feet get cold so quickly even when they wear thicker socks. They blame it on their shoe covers. They think the shoe covers they bought are not working. In reality it’s the snug shoe fit that is preventing their feet from staying warm.

In cold weather conditions you need to wear shoes, or preferably boots, that are at least one size bigger then what you normally wear. Even better for extreme cold is a boot at least two sizes bigger. I remember Mike Curiak saying he wore a Lake Winter Cycling boot that was five sizes bigger for temps in the -40 to -50 range in the Alaska endurance races he did.

It’s the extra air space that allows the full loft of your socks to insulate your feet.

Here is the system I use:

On my feet I wear a simple polypro liner sock combined with a Smartwool Hiking sock. This is the only thing I wear for socks whether it’s 50deg F or -30deg F. That’s an 80 degree temperature range. With the exception of a vapor barrier, I don’t add any other layers as it gets colder.

The vapor barrier I use is made by Integral Designs. A plastic bag will work nearly as well. I will wear these layered between the liner and the wool sock. I won’t ever use these for rides or commutes under an hour long. On longer rides in temperatures below zero degrees Fahrenheit it traps any moisture from your feet inside the VB sock. By not allowing the moisture to pass through to your wool sock it keeps that all important insulated layer completely dry. Wetness will rob heat from feet. Moisture also decreases the loft of your sock thus decreasing the insulating properties of that outer sock layer.

I will wear my summer shoes in dry conditions down to a temperature of about 35degF. In wet conditions up to 50degF or any conditions below 35degF down to about  zero degF I wear my Lake MXZ302 Winter Boots. Essentially I wear these boots from November until April in the climate I live in. Back in 2006 when I bought my first pair of winter specific cycling boots, the Lake MXZ301, it was the only winter boot on the market. 45NRTH wasn’t even a company yet. A few years ago I replace the 301’s with a newer 302 model. Since then they have redesigned it and released the 303. I bought one size bigger than I normally wear. If I understand it correctly the 45NRTH winter boots are sized so you buy the same size you wear in the summer. The required “air space” is built into the fit for each size.

When the temperatures drop below the zero degree mark Fahrenheit, as they often do in winter here, I switch to platform pedals and a pair of insulated hiking boots I bought on summer clearance for $50. Two sizes bigger then my normal foot size. The boot fits snug in the heel. The bigger size gives me generous “air space” in the toe box. I’ve taken this boot down to -32degF and never got cold toes.

The insulation provided by the wool sock combined with the air space in the toe box provides an enclosed area that maintains the heat and warmth my feet put out. A windproof insulated boot keeps the heat in that air space intact and does not allow it to be pulled out. Obviously you would not want to wear a ventilated summer boot. It would allow all the heat to be moved away from the foot.

For longer rides below 20degF I will add some warmth to the toe box with a chemical activated hand warmer. I’ve found hand warmers work better than the toe warmers. These type of warmers require oxygen to keep them activated. The air space provides this.

In really extreme cold with windchills in the -30degF range and colder I will add an outside wind protection layer. I use a product made for downhill skiing. It’s a neoprene front of the boot cover. It says it will add 20 degrees of warmth. I’ve found that to be accurate.

If you get nothing else from this article, just remember it’s the “Air Space” in the toe box of your footwear that allows you to maintain warmth. It’s not the price of the boots or the number of socks you wear that determines how warm your feet will be.

Stay warm and happy biking.