Q: Nail in tire. Been driving with it. Slowly leaking. Left to park for now. Is the tire unrepairable to a point?

Hello, thank you for writing in. The tires need to be evaluated a little further before we justify getting a new one put on, or patching it. Take a look at the tread, and make sure it is evenly worn and still ample. If the tire was older, consider getting a new one. The second consideration is that the tires will develop fit spots after sitting for an extended period of time. If this is the case, you may want a new tires, or 4 new tires if extremely worn and flat. Newer and fresher tires will bounce back from a flat spot better than an older and weathered tire. They will also respond to the patch better. Take a good look at the condition of the tire in question, and then at all of the tires.