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It all depends on the year frame and style. Early BMX would have 44-46 T up front but modern frames will only use around 25T or so.
That's not true. Modern bikes are still based around 44:16 nominal. I still run 43-45 and a 16T rear. That's still by far the most common on race bikes.
The smaller cogs on the freestyle-specific bikes cause more drivetrain losses, wear faster, and are more likely to slip on a full-power gate start. Way back the trick-only guys used to use the race bikes, which were built around 44:16.