So i have to buy new rims for my Dodge ram 2500 -97. I have 37x13,5'' tires and only 8'' rims right now. The only place i could find that sells rims wider than 8'' is summit racing, but i was sort of confused when i read the specs for 2 rims that i was interested in.

So rim nr1 has these specs

Wheel Diameter: 16 in.
Wheel Width (in): 12.000 in.
Backspacing (in): 4.375 in.
Offset: -54.00mm

Rim nr2

Wheel Diameter: 16 in.
Wheel Width (in): 12.000 in.
Backspacing (in): 4.375 in.
Offset: -25.00mm

How is it possible that they have different offset when the backspacing and width is the same?

Anyone have any idea what measurements i should have? I don't know what offset etc i have right now but the tires are grinding the control arms when i turn the wheels too much..

Also, center diameter of the wheel, is it important to have the exactly right diameter when you have such big wheels?

 

Hope this diagram explains it, It's the way it's made. You can have the same measurements but still have a larger offset.




http://www.crawlpedia.com/wheel_dimensions.htm