How Can Figure Out The Backspacing On 20x9.5 20mm Offset Wheel

[Lincoln30]

I've changed my mind about the 285/55/20 BFG and want to go with the Nitto 305/50/20 which is the same diameter but wider tire. Since I don't have the truck yet, I'm concerned about fit/backspacing. I will do a 2" leveling kit and would someday like to move to a 305/55/20 tire (33").

[hubbycap]

Backspace of the wheel would be determined by measuring the overal width of the wheel, probably 10.5" (9.5 + about an inch for the flange thickness) and dividing in half = 5.25". The offset of the wheel is 20mm or about 3/4" from the center of the wheel. Since you expressed the offset as a positive number, add the offset to your 5.25" = 6". This does not allow for the inch or so that the tire extends beyond the flange.

[Lincoln30]

Thank you, that's what I needed to know. I'm not sure if the offset is positive or negative but now I know how to calculate it once I find out.

[c4cruiser]

Backspace is the distance from the wheel mounting flange to the inside edge of the wheel. Offset is the distance from the wheel mounting flange to the wheel centerline.

 

A Positive offset is where the flange is closer to the front of the wheel centerline and a negative offset is where the flange is closer to the backside of the wheel past the centerline.

 

Wheelwidth plays a part in the two measurements, as does the location (and thickness of the mounting flange) of the wheel center within the wheel rim. For a given wheel width, if offset changes, so does the backspacing.

[Controller]

http://www.1010tires.com/WheelOffsetCalculator.asp

 

See the above link, this will tell you how far your new wheels will stick out.