alright.... i'm in the market for new 20s... I have a 2004 Screw Lariat...
I'd like to know the perfect offset and backspacing to where when i run a 275/55/20 the outside edge of the tire is flush with the edge of the fender well. Help please!!

 

Your OEM wheels are 7.5 inches wide with 5.5 inches of backspacing. You can use that as a guide. Maybe some members with 20's will post some pics of their setups.

 

Guitarman,

The tires that you mentioned are just under 11" wide. Mine(285/65/20) are a little over 11". They hang outside the wheelwell about 3/4" on 8.5x20 wheels with 5.5" backspacing. Pics in the gallery.

JV

 

this may not be much help but i plan on running my 8.5" x 20" wheels w/ 6" of backspacing with about a 305/60R20 toyo mud terrain...if i did the correct calculations, they should stick out about 1/2" on the sides.

 

thanks guys.... i'm just in the wheel market and i dont know much about offset and backspacing.