33x12.50 Toyo MT PSI?

Anyone running these on a 20x12 wheel? If so what psi do you recommend? I am currently running it around 50psi..

 

A lot of people use the chalk test, draw a line across the tires tread surface, drive around and check to see if the chalk scrubbed off. If there is still chalk visible on the edges, lower tire pressure and try again. This ensures a even contact patch, and the tires will wear better. With tires that wide, you could run higher pressure than the chalk test to get better MPG, but the tires will wear faster in the center. Typically the front tires require more pressure due to supporting more weight, but it all depends on how our truck is loaded.

 

this

Here's a Ehow article if you need even further clarification

http://www.ehow.com/how_6948382_chalk-tires.html

 

Thanks guys! This website is unreal! I'm new to trucks and appreciate the help! Jeff at Maui off road set it to around 50 psi.. Just wanted other opinions.. Mahalo!!