Offset and Tire size

[ducatijosh]

Hello, I'm trying to wrap my head around backspacing an offset. If the tire sticks out further than the wheel why is backspacing always mentioned in lift kits rather than offset?

a 17x8.5 0 offset wheel will have 4.75" of backspacing
a 17x9 0 offset wheel will have 5" of backspacing

Technically the same 12.5" wide tire should be in the exact same spot on these wheels though right? Since the tire sticks out further than the wheel why does backspacing matter?

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[Chunky White]

The wheel can rub on suspension parts and is smaller in diameter than the tire so its range of travel if on a different arc. The tires rub on fenders, frame etc.

backspacing is the difference from the inside of the wheel to the rear and of zero should put the center part of the wheel in the center of wheel versus positive which moves the wheel inwards or negative which moves the wheel outwards

sorry I am typing out my ass but thats my thougts

 

[Kevin_D]

https://www.carparts.com/blog/wheel-backspacing-vs-wheel-offset-charts-and-table-included/

You're welcome.

Kevin

 

[Discount Tire]

If you haven't already, here's a good thread to review:

https://www.jeepgladiatorforum.com/forum/threads/backspace-and-offset-how-do-they-relate.32829/

Equal backspacing will always have the same clearance towards suspension components. In your example, the 9 with 0 offset will sit 1/4" closer towards the suspension and 1/4" further outwards compared to the 8.5 with 0 offset. Here's a visual, orange is the 8.5 ET0 and blue is the 9 ET0.

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