This past Friday I did two bicycle related things I’d not done before. First time on a single speed mountain bike and first time on a fat bike. What is a fat bike? A fat bike (or snow bike) is a bike with REALLY wide tires. 3.5″+ wide. Surly has two models in their lineup, the Pugsley and Moonlander. Salsa has one, the Mukluk. What are the benefits of really wide tires? There are several. First, the wider tire has a larger air volume. Larger air volume means the tire can act as a suspension of sorts, absorbing impacts with any number of obstalces. Second, the tire is run at lower pressure, as low as 8 psi. This allows the tire casing to deform as it encounters obstacles, again acting as a suspension but also increasing traction as more of the tire is in contact with the ground at any given time. Third, the contact patch is larger. The larger the contact patch the more float the tire has and the easier it rolls over soft surfaces like sand and snow. The larger contact patch also lessens the impact to the trail. Combine all these benefits and it equals serious FUN.
I was riding on the west side of the Estrella mountain range, where the roads are mostly sandy, occasionally as deep as beach sand. Off the roads the surface varies from hardpack to 4″ – 6″ riprap. Topography varied from flat to rollers much like those found around the buttes at Papago Park. The Pugsley I was riding rolled over all these surfaces with relative ease. While deep sand required more effort, the tires did not bog down like an ordinary 2″ wide mountain bike tire would have. I was especially impressed with the ride quality over 2″ – 3″ gravel, the aired down tires made it feel as if riding an ordinary bike on hardpack, quite smooth. Another terrain where the wide tires excelled was riding over channels in the sandy soil as much as 12″ deep and two feet wide created by rainwater draining to lower elevation. An ordinary bike tire impacting the sharp edges of the channels would have cut in like a knife slowing the bike significantly. The nearly 4″ wide tires however, rolled over and through these channels quite easily. I’m pretty sure I had a big goofy grin on most of the ride and every time new terrain was conquered I’d often laugh with amazement. I was also amazed that I really didn’t miss a geared drivetrain much, 32×19 was a pretty good ratio for a fun roll through the desert.