Wheel backspacing and offset defined:

BigRogers · 2013-03-12T02:08:12+00:00

Intent of this thread is to try and help others learn, as well as teach myself (if the math is correct) how to determine backspacing and offset of just about any wheel. Layout and terms of the wheel: So using this link for my reference http://www.toyota-4runner.org/3rd-gen-t4rs/33980-stock-oem-4runner-rim-offset-backspacing.html#post288655 This 16” 3rd gen 5-star measures the wheel width as 7”, this makes a wheel center 3.5”. The backspacing is 4.625". This is achieved by measuring the distance of the backside of the wheel to the mounting surface as shown above. If I understand correctly the wheel offset is calc’d by subtracting the wheel center from backspacing (Bs-WC=Offset). Doing the math that would leave this wheel to have a positive offset of 1.25" or 28.5mm. Positive offsets are when the backspacing is greater than the wheel center (4.625”>3.5”) Now throwing wheel spacers in, a 1.25" spacer subtracted from the initial backspacing of 4.625” brings the relative backspacing to roughly 3.375”. This would create a negative Offset as the Wheel Center is now greater than the Backspacing (3.5”>3.375”) Let me know if you see any math or methods that are incorrect and I will edit to make right.

Thread starter BigRogers
Start date Mar 12, 2013

Luke325i

New member

Dec 30, 2018

Awesome thread. Thanks. So using this guide the following wheels appear to have a backspacing of 5.43" :

Here are the wheels i want to put on my 3rd gen which, according to the first post, has a backspacing of 4.63".