I run 36" GY Wrangler MT (16.5" humvee tires and I am running@ 9oz of STEEL BB's in mine. Why steel BB's? denser, don't/can't clump up when you get moisture in your tire from the air compressor at the gas station and when I get a flat I unseat the bead and put a magnet in and pull them all out at once until the plug/patch dries and then put them back in.
IIRC basically a quater of a cup of steel BB's and you will be fine.
FWIW I have done this for years.
Here's a write up I did:
"Axeheads are supposed to be sharp, but you are one blunt tool."
If you love wealth more than liberty,the tranquility of servitude more than the animating contest of freedom, go home from us in peace. We seek not your counsel nor your arms. Crouch down and lick the hand that feeds you. May your chains sit lightly on your shoulders and may posterity forget that you were our countrymen.
A government big enough to give you everything you want is big enough to take everything you have.
Calling Illegal Aliens "Undocumented Immigrants" is like calling drug dealers "Unlicensed Pharmacists"
Nemo Me Impune Lacessit
"No one provokes (attacks) me with impunity".
"Your right, the Tea Party and the OWS are the same, just like the America Revolution and the French Revolution were the same. The only problem is the American Revolution ended with Liberty, Freedom, Justice for all and a shining light upon a hill. The French Revolution ended with lynchings, guillotines, murder and socialism. So yeah, I could see how one could confuse the two..."