Although Sams Club sells great tires, their tire installation service is terrible. On the two occasions I had them install some tires, both times they performed an inadequate job.
The first time I had them mount some tires was in 1995 where I bought a set of snow tires. Shortly after installing them the car began making clicking/thunking noises while turning. The boot on the drive axles was torn, so I assumed it was the noise of a failing CV joint. Over a few weeks the noise greatly increased and I had to hobble the vehicle to a suspension shop to presumably repair the drive axles.
When I got there, the mechanic put it on the lift and told me what the real problem was. Apparently the had forgotten to tighten the lugnuts on one wheel! The wheel was working it's way loose off the car. I could have been killed! The aluminum rim had sustained some damage and I had to have the wheel hub repaired because one of the lugs broke off. Too much time had elapsed between the tire installation and the repair job that it would not be practical to take this matter to small claims court.
In 2002, I threw caution to the wind again and had them install 2 new tires on my car. Luckily nothing went horribly wrong except for the fact that they did not bother to inflate the tire to the right pressure and they did a crummy job balancing it. I had to pay a tire shop for a rebalance.
In summary, the tire installers at Sams Club are probably minimum wage unskilled labor that do not have the proper experience or attention to detail that makes them qualified to perform service on such an important part of a car's safety.
Do not trust these people with your car!!