MTB BSA BB's are typically 73mm. To run a BB92 you need to use a BSA crank. A few 30mm spindle cranks have a spindle length long enough to use in a BB92 shell, like Rotor, Raceface, and E13. PF30/BB30 cranks have too short of a spindle to run a BB92.
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Sorry, I still have one doubt @RS VR6
The frames for BB92 and for BSA are the same, I mean the BB zone