By the way, if you buy your tires from Costco, in addition to 2% or 4% off (executive membership + Costco Visa), they will install them and do wheel alignment for you, which is included in the price of the tires.
They also have absolutely free for everyone Nitrogen fill on their parking lot. Never pay extra for that stuff.
They warranty and pro-rate damaged tires also, like a lot of tire shops. I typically don't use them simply because they're busier than a tire shop these days in my area, but the deals can be good if they have the tires you're looking for. I have 3 tire shops and a Costco within a few miles, so whoever is available and cheaper lol. I generally use a friend's shop as they are a confirmed drop ship shop for Tire Rack. I order the tires, they show up there and I drop the car off.
I don't think I'd ever get my alignment done by Costco though. Two of my friends own race shops and they both have serious alignment hardware. One of them has the only Bosch 3D laser alignment machine in the area; it can detect a bent frame. Getting my ~10yr old AST shocks rebuilt there next week, which obviously requires an alignment.
Nitrogen is more stable, but in reality, the benefit is minimal.
The results show that nitrogen does reduce pressure loss, but the reduction was only a 1.3-psi difference from air-filled tires over an entire year.
