In first grade at St. Pius X School, Sister Thomas gave my class a free period each week to reflect upon our sins. Inspired by a library book about sea animals, I sometimes spent it daydreaming about riding a walrus, which I admired for its immensity and the fact it could swim faster than cars were allowed to drive in my neighborhood. It conjured a feeling that was equal parts ponderous and agile; atop a walrus, I would be nimble among obstacles, yet able to plow through anything unavoidable.
Almost 40 years later, I get exactly the same feeling riding a fat bike in the Bridger-Teton National Forest near my home in Jackson, Wyo. With tires five inches wide, a fat bike is tank-like rather than tottering and able to roll over almost anything in its path. The shape of its frame — similar to that of a mountain bike, but with a wider fork and hubs to accommodate the ginormous tires — makes it agile enough to negotiate flowy, single-track trails through the trees. In the snow.
The purpose of a fat bike’s fatness is to allow it to stay on top of compacted snow. (For the purpose of this story, at least. Fat bikes can also be ridden on sand.) Compacted snow means many things: trails groomed for Nordic skiing, trails groomed specifically for fat biking, snowmobiling trails, trails packed down by snowshoers, and even snowy roads. Depending on how heavily compacted the snow beneath is, a fat bike can handle about two to three inches of fresh snow without “wallowing” — when tires, which can be studded or not, wash out because they can’t get any purchase.