The War-Wheel was a massive battlecruiser used by the Sontarans. The ship looked like an axle with two wheels on its ends. It was armed with two space cannons, carried Sontaran shuttlecraft and was captained by an Admiral.
Sontaran Commander Steg intended to open a wormhole above Sentarion and send a War-Wheel through it to Ruta III, where it would kill the Rutan Queen. The Seventh Doctor closed the wormhole and trapped the War-Wheel inside. (PROSE: Shakedown)