Can someone give me a quick lesson on offset?

2017 TRD Sport, lifted 2.5 inches running factory sport wheels 17" x 7.5". From what I can find the factory wheels have an offset of +30. The wheels I am looking at are 17" x 8.5" with an offset of +10. So is it as simple as the new wheels will stick out 20mm more than the factory wheels?

I have looked at different articles on the internet and I am still confused. Thanks in advance.

 

The wheel would poke 30mm.

That backspace might not work with your lift.
Stock is 5.43; 17x8.5+10mm is 5.14"

 

https://www.tacomaworld.com/threads/wheel-backspacing-and-offset-info.102992/

 

https://www.tirerack.com/tires/tiretech/techpage.jsp?techid=101

 

The new wheel would stick out 32.7mm out further then your stock wheel. The aftermarket wheel is 1inch wider half of that goes towards the outside and half to the inside. An example would be if the oem is 17x7.5 +30mm and aftermarket is 17x8.5 +30mm then the aftermarket wheel would be 1/2 and inch further out aswell as in towards the knuckle/ control arm. 1/2 inch equals 12.7mm plus the -20mm of difference between the oem offset equals 32.7mm further out and 12.7mm inward

 

The 20mm plus half of the 1" difference in width. 1"=25.4mm divided by 2=12.7 12.7+20=37.5mm.

 

12.7+20=32.7

 

Probably the best tire/wheel calculator out there.

https://www.rimsntires.com/specspro.jsp

 

You are correct must have been a typo.

 

That is a fantastic help. Thanks!