Asuming you have 4 tires and 2 axles, you need at least 8000/4= 2000 lbs maximum load a tire.
Found with google LT 195R15 Loadindex 106/104 wich is maximum load a tire single 2050 lbs , and Dual 1984 , so for dual load axle ( 1 axles with 4 tires on it) to less , and for tandemaxle so 2 axels and 4 tires total , eanaugh to law but a bit poor .
But if you never load it fully , it would be enaugh.
When you load it to the max , minimum of 10% reserve would be nice for unequall load R/L , little overloading.
So that would mean a loadindex of 108 would be needed with 2205 lbs maximum load.
These are the things you have to take in to account when searching for tires.