When the glaciers retreated from the last ice age, Surly collectively toweled off, slapped on some Brut, and beheld a vision of a single speed future. To that end, we offered single speed products when those were hard to find, expensive, or both. One of our earliest sets of bits was a pair of 1x1 mountain hubs designed to work with a single bmx freewheel. They were pretty cool. From…