Surly ExtraTerrestrial Tire

The ExtraTerrestrial is designed for mixed-terrain versatility. While it rolls efficiently on pavement thanks to its directional tread, the robust construction and puncture protection make it highly capable on gravel, dirt roads, and light trails.

While it is tubeless-ready, you can absolutely run it with standard inner tubes. The folding bead and durable casing work perfectly fine with a tube setup if you prefer not to deal with sealant.

We recommend using a rim with an internal width between 23mm and 30mm. This range provides the optimal tire profile for stability and cornering grip without causing the tire to feel squirmy or overly squared off.

This tire uses a dual-layer approach: a Kevlar cap directly under the tread to stop sharp debris from penetrating the main contact patch, and a nylon breaker in the sidewalls to prevent cuts from rocks or trail obstacles.

The maximum recommended pressure is 60 PSI. However, if you are running them tubeless, you will likely find better traction and comfort by experimenting with lower pressures, depending on your total bike and rider weight.