If you're wondering why our bikes are made with steel frames, Mission Bicycle has a great article about steel vs. aluminum.
TL;DR: Steel really is the best, strongest, and most durable material for a bicycle that's meant to get you from A to B.
What's particularly important for us is the part about durability. When a high-quality steel frame is taken care of, it has no defined expiration date. Steel can take a beating, rebound to its original shape, and keep going.