These are for a B737-300. My guess is that the -200 limits would be pretty similar. ( I could of course be outrageously incorrect in that!!)
Braking action Good =35kts ( >.4)
Braking action Med/good =30kts ( .39-.36)
Braking action Medium = 25kts ( .35-.30)
Braking action Med/poor = 20kts ( .29-.26)
Braking action poor = 15kts ( <.25)
Boeing suggest a max
windspeed for taxying of 65kts, I think some Ryan drivers misread that as a min forward speed for taxying
??