Small holes in the center of the tread are generally repairable. Holes on the side of the tread or on the sidewall are fatal to the tire. We’ve cut tires and filled large holes with plugs on the trail to get back to the trailhead. Driving down the road at speed with a large tire plug is a bad idea because the damage can get worse and the plug can easily get dislodged, which will cause the tire to go flat fast. It’s not a good idea for a 4x4 that will see road driving and highway speeds.