Check the "On Duty" tab; it will show you the minimum.
The community, on the other hand, wants higher. Back in the day of Gates, CR 90+ was asked of you.
OK, but if I am CR 84 does that make me a Tier 5 player? Obviously I have to get the armor, etc.
When people look for a T5 player, they want that person in T5 items to be able to tackle the content flawlessly. They know that having a CR of 84 mean you don't have the required gear, as higher tiers of gear boosts CR.