I'll admit I've mostly been mindlessly scrolling this thread to this point, so I'm not 100% sure what others have said, but removing the valve stem core will deflate a tire in seconds. You might want to unscrew slowly, to avoid the core launching across the parking lot as the air pressure behind it will likely send it flying, but once it's removed a tire should be completely flat in 15 seconds or less.

[–] SchmidtGenetics 2 points 3 hours ago* (last edited 3 hours ago) (1 children)

https://youtu.be/0E-z3DTdpKU?si=lyUke-C2csZ2diUv

It’s not a few minutes, why the obvious lie?

Anyone who has actually tried this know it’s not that fast.

[–] MrMcGasion 1 points 2 hours ago

Yeah, the speed of the rock/bb in the cap will vary a lot depending on how far it depresses the valve stem core, and the tightness of the thread on the cap. Minutes seems absolutely unrealistic though; at the rate of the video you shared that's probably a good 6-8 hours. I'm sure with some optimization (larger "rock" to press the valve in further and a maybe some cuts in the the thread to allow faster release of air), you could get that down to the hour or two range, but you'd also risk someone finding it easily as the noise of escaping air would be quite a bit louder.