how much air in my tires

i have a 300ex with 20" turf tamers and i was wondering how much air i shoud run with, if you could tell me how much you guys run it would help, thanx
joe

[Razorback]

5 to 7 psi should work. 5 will hook up a little better, while 7 or so will slide a little better, but it might ride a little rougher also.