SO I just got new Goodyear's put on my 95 accord. Cool, right? Well I also went to a junk yard and bought this rim and got the tire place to put one of the used ones (still is okay shape) on the rim I just bought. But now the POS has leaks out 10 PSI in just a few days. Now I'm not sure if they just damaged the tire when transferring it or if I got a bad rim. Right now I can't figure out if I need just a new tire or a new rim and tire. I really need a full sized spare on board for my peace of mind as I'm about to set out on a loooong drive. What ya think?

 

Bring it to any garage that replaces tires. They should have a tub with water that will allow them to dip the tire/rim in enough to look for any bubbles.

 

Yea I guess that's the obvious answer. I'll prob do that tomorrow. Would a rim have to be 'obviously' damaged in a severe way to make a tire leak? Either the tire was damaged or wasn't mounted right, or I bought a bad rim, I can only conclude. I mean the rim looked dirty and crusty... but idk.

 

Depends.
With rims they can fail from stress fractures. I've failed steelies. Induced a load to cause the hub to hoop welding to crack causing a leak. Aluminum if there is cracking may cause leaks as well.
If the tire bead is corroded the tire will not have an air tight seal.
Bad valve or corrosion/cracking around the valve seat.