Abstract: A safety clamp to be locked onto a rim while a tire is being mounted and inflated thereon using a retaining ring, the safety clamp having a rigid frame with peripheral portions overlying the rim and ring assembly and the tire, and the frame supporting plural locking members which are expanded to underlie the rim and the tire bead and lock the clamp thereto when a central rod is lowered, but the locking members being retracted when the central rod is raised thereby to release the safety clamp and permit its removal.