my guess is there was probably a ton of force since the door got pulled from nearly closed to fully open (actually past that point, obvi) at like 70mph. it made an absolutely horrendous sound and i had assumed the door actually folded since it was moving so fast. I think the only reaso it survived is because it thankfully smashed up against a gigantic nylon clamp that i had on my farm jack instead of just smashing directly against the fender