Aftermarket 20" rims

[Gadwall]

I have a 2011 Sierra SLE with the OEM 20" chrome wheels and am toying with replacing them with aftermarket wheels. My question is what is the OEM offset if I want the same look with the aftermarket rims? I do not have 4x4 and its not lifted; so, I really just want the rims to sit as far as possible to the outer edge of the fender wells. I do not want the tire outside the wells. Also, how do you determine if you should go with a 20x9 or 20x10 rim size? And just to be certain: the OEM wheels are 6x5.5 on the lug pattern, correct? Thanks.

[LTZ2014]

You'd want a 20x9 and also a high positive offset I think stock is like +31mm.

 

 

 

[cparks555]

You'd want a 20x9 and also a high positive offset I think stock is like +31mm.

X2