Overdriven pulley how much is too much?

This is where book smarts and theory crash head-on with actual experience and reality .
In theory by the smartest folks on the planet, in their field, thought the Stage seal was good, the Challenger's crew experience proved different .

That was a known weak point, flaw, and known piss-poor design. Engineers couldn't make managers spend the money to fix it, and instead insistend on using up inventory on hand and then also didn't listen when told there was no way in hell it would be safe after the cold soak the parts got.

Theory always wins. It explains why things behave the way they do. When they disagree, there's always other variables not being considered.