Wheel width will play a factor in the specs needed to get your desired result. A 10" wide wheel will need a higher offset than say a 8" wide wheel to sit (stick out or not) the same. So as an example lets say that you have an 8" wide wheel that sits perfectly flush with the fender. The offset is -0- (so 20x8 with zero offset). If you want the same exact fit with a 9" wide wheel you will need to find a wheel with an offset of +12mm to sit flush with the fender. Lets say you want a 10" wide wheel and you want the same exact fit, you will need to find one with a +24mm offset. So with that said find a set-up that you know the specs of ( width, back spacing and offset) then do the math from there. Without knowing the specs of the truck pictured it's hard to say. If I had to guess I would say that the wheels are probably 9" wide (assuming thats a 35x12.5 tire) with an offset of about -10 ish
Here is a pic of my truck, it's not the greatest but its all I have right now. The wheel specs are 20x9 -6mm. As you can see they stick out slightly.
You will also have to factor in the fender flares. If you have flares that stick out 1.5" you will have to add that to the wheel specs to get the same fitment.
As an example on my truck. If you wanted the wheels to stick out past the flares exactly the same as they do now without the flares you would need a wheel with an offset of about -38mm (vs the -6 and assuming a 1.5" flare). Or step up to a 10" wide wheel and go with an offset of about -26mm.
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