4/7 drop and 18” tire size?

[15RCSB]

Hey everyone, new here just purchased a 15 rcsb Sierra. Belltech 4/7 drop on the way, curious about 18in tire size with the drop.

 

cant seem to find anything but 17” and 20”+ topics, what’s the ideal size for an 18” and a 4/7 drop, thinking 265/55r18 or possibly 60, factory is 265/65R18? 
 

 

[14 Silvy]

I put a 4/7 drop on my buddies 16 regular cab and it had the stock 18's with 265/65/18 on it. Now it has 22's with 265/40 front and 305/40 rear.

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