I wouldn't bother. I'm a car guy, and super cheap, but used tires are like a used mattress. You just don't.
I might make an exemption for snow tires. Since they won't be used at high speed and low miles anyway.
I, too, am really curious why people are recommending not to buy used tires. It's not like my car is going to get tire-bugs from used rubber. My last two sets of tires have been used, each with 50%+ of the tread left... they've worked fine for me.
Am I missing something here? What harm can come to my vehicle from buying used tires?
Used tires are not the deal you think they are.
50% tread? Even if you paid a 75% discount from new price I wouldnt touch them.
-You say 50% tread. From what? did you measure depth to the indicators or the groove? Do you also know that tread depth is commonly understated by mfg's? That 50% wear may really be 65% compared to a new tire.
-Rubber degrades with time, environmental and uv exposure, even when not driven.
-Used tires are more likely to be older models, and tires are under rapid development recently, with better stability, better manufacturing and improved rolling resistance.
-You don't know the usage. A tire may have been abused on potholes and you may not be able to see the damage. More likely to have a blowout.
-You're missing out on the best part of a tire's life. Tires perform best in passenger cars when they are new with 50%+ tread. The ride is smoother, easier on the car. They perform better in the wet with full deep grooves.
-Labor. Buying used tires simply means you need to mount/unmount and balance more often. This is already a significant expense when considering new tires, and it doubles when you think about used tires.
Used tires are false savings unless you need to get a car on the road to sell it or something.
I just purchased new tires for my car myself (pirelli cinturato p7 all season plus 205/55/16)
$413 from Sam's and had a friend mount balance them for a $10 lunch.
Driivng a car on new tires makes it feel new again.