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We've seen a few questions come up recently regarding this topic so we thought this write-up may be useful for those considering aftermarket wheels. This is a high level overview and the examples shown are not specific to the Bronco 6G fitment.

Mods feel free to sticky if found beneficial.
_______________________________________

Offset and backspace are essentially two different ways of looking at the same thing. They determine the location of the wheel and tire assembly when bolted to the vehicles hub.

Offset is the measured distance between the hub mounting surface and the wheels center line.

With X being the determined offset, the hub mounting surface on positive offset wheels is X amount forward from the wheel center line. The hub mounting surface on negative offset wheels is X amount backwards from the wheel center line. The hub mounting surface on 0 offset wheels is the wheel center line.

Backspacing is the measurement from the hub mounting surface to the back edge of the wheel.

Ford Bronco Wheel Offset and Backspace | How do they relate? 2021 Bronco wheels offset backspace


***Typically speaking, the higher the offset/backspace, the more the wheel will tuck inwards towards the suspension or away from the fender. The lower the offset/backspace, the more the wheel will push out away from the suspension or towards the fender.

For Example:

*If the offset on a 9" wide wheel is +12mm, the hub mounting surface will be 12mm forward from the wheels center line. Measuring from the hub mounting surface to the back edge of the wheel, the backspacing is 5.5"

*If the offset on a 9" wide wheel is -12mm, the hub mounting surface would be 12mm towards the back of the wheel from the wheels center line. Measuring from the hub mounting surface to the back edge of the wheel, the backspacing is 4.5"

Here's how to calculate the backspacing using the rim width and offset:

First - add 1" to the rim width and then divide by 2 to find the wheels center line (you have to account for the wheel flange which is why you add 1" to the rim width) . Second - convert the offset which is in millimeters into inches. There is 25.4mm in 1 inch so divide the offset by 25.4. Lastly - add the converted offset to the wheels center line if the offset is positive for the correct backspacing. Subtract the converted offset to the wheels center line if the offset is negative for the correct backspacing.

For Example:

17x9 +12mm offset

*9" rim width + 1" = 10"
*10"/2 = 5" (wheels center line)
*+12mm offset/25.4 = 0.47" (0.50" rounded up)
*0.50" + 5" = 5.50" Backspace


17x9 -12mm offset

*9" rim width + 1" = 10"
*10"/2 = 5" (wheels center line)
*-12mm offset/25.4 = 0.47" (0.50" rounded up)
*0.50" - 5" = 4.50" Backspace

***Please note that the wheels center line is the backspacing for 0 offset wheels.

Check out our TIPS & GUIDES Section at discounttire.com for more helpful write-ups!

Here's an offset/backspace chart for quick reference:

Ford Bronco Wheel Offset and Backspace | How do they relate? 1607714222731
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AcesandEights

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Timely post. Thanks.
 
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For those that keep sticking up for Ford's absurd positive offset note that at 8" and 8.5" widths The Bronco Offset isn't even on the chart...
Can you explain further what you mean by this, and the implications for us as buyers?
 

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For those that keep sticking up for Ford's absurd positive offset note that at 8" and 8.5" widths The Bronco Offset isn't even on the chart...
Good call out, the chart doesn't cover all offset/rim width options. It is a good reference for aftermarket wheels which typically utilize lower than stock offset.

If the factory wheels are 8-inches wide with +55mm offset, the backspace works out to ~6.6-inches of backspace

If the factory wheels are 8.5-inches wide with +55mm offset, the backspace works out to 6.9-inches of backspace.
 

ATLBronco75

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Can you explain further what you mean by this, and the implications for us as buyers?
Finding off-road wheels with stock offset is next to impossible. The vast majority of the off-road wheels you see out there are 0 offset.
 

Adumb

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Finding off-road wheels with stock offset is next to impossible. The vast majority of the off-road wheels you see out there are 0 offset.
Thank you. This is over my head, and that's ok. To the mall I go.
 

mspeter

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Compared to zero offset, high positive offset allows for wider a-arms, ~2” longer front halfshafts/better max CV droop. Hopefully more than a couple of +55mm offset choices from the aftermarket.
 

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Finding off-road wheels with stock offset is next to impossible. The vast majority of the off-road wheels you see out there are 0 offset.
What this information does not discuss is scrub radius. Yes, most aftermarket wheels have zero (or close to it) offset but that is needed or desirable for stability and due to typically taller tires. A wheel needs to "stick out" more when the tire is taller to keep the steering functioning properly. Look up scrub radius.
 

accord77

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We've seen a few questions come up recently regarding this topic so we thought this write-up may be useful. This is a high level overview and the examples shown are not specific to the Bronco 6G fitment.

Mods feel free to sticky if found beneficial.
_______________________________________

Offset and backspace are essentially two different ways of looking at the same thing. They determine the location of the wheel and tire assembly when bolted to the vehicles hub.

Offset is the measured distance between the hub mounting surface and the wheels center line.

With X being the determined offset, the hub mounting surface on positive offset wheels is X amount forward from the wheel center line. The hub mounting surface on negative offset wheels is X amount backwards from the wheel center line. The hub mounting surface on 0 offset wheels is the wheel center line.

Backspacing is the measurement from the hub mounting surface to the back edge of the wheel.

Ford Bronco Wheel Offset and Backspace | How do they relate? 1607714222731


***Typically speaking, the higher the offset/backspace, the more the wheel will tuck inwards towards the suspension or away from the fender. The lower the offset/backspace, the more the wheel will push out away from the suspension or towards the fender.

For Example:

*If the offset on a 9" wide wheel is +12mm, the hub mounting surface will be 12mm forward from the wheels center line. Measuring from the hub mounting surface to the back edge of the wheel, the backspacing is 5.5"

*If the offset on a 9" wide wheel is -12mm, the hub mounting surface would be 12mm towards the back of the wheel from the wheels center line. Measuring from the hub mounting surface to the back edge of the wheel, the backspacing is 4.5"

Here's how to calculate the backspacing using the rim width and offset:

First - add 1" to the rim width and then divide by 2 to find the wheels center line (you have to account for the wheel flange which is why you add 1" to the rim width) . Second - convert the offset which is in millimeters into inches. There is 25.4mm in 1 inch so divide the offset by 25.4. Lastly - add the converted offset to the wheels center line if the offset is positive for the correct backspacing. Subtract the converted offset to the wheels center line if the offset is negative for the correct backspacing.

For Example:

17x9 +12mm offset

*9" rim width + 1" = 10"
*10"/2 = 5" (wheels center line)
*+12mm offset/25.4 = 0.47" (0.50" rounded up)
*0.50" + 5" = 5.50" Backspace


17x9 -12mm offset

*9" rim width + 1" = 10"
*10"/2 = 5" (wheels center line)
*-12mm offset/25.4 = 0.47" (0.50" rounded up)
*0.50" - 5" = 4.50" Backspace

***Please note that the wheels center line is the backspacing for 0 offset wheels.

Check out our TIPS & GUIDES Section at discounttire.com for more helpful write-ups!

Here's an offset/backspace chart for quick reference:

Ford Bronco Wheel Offset and Backspace | How do they relate? 1607714222731
So in plain English please what the biggest size tire I can fit lower then the Badlands trim. meaning base, big bend and black diamond non-sasquatch 17 inch rim Discount Tire thanks Tire Rack did not know
 

buzpro

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So in plain English please what the biggest size tire I can fit lower then the Badlands trim. meaning base, big bend and black diamond non-sasquatch 17 inch rim Discount Tire thanks Tire Rack did not know
Bottom line, in plain English: NOBODY can tell you until they get their hands on a Bronco
 

Dads_bronze_bronco

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Good call out, the chart doesn't cover all offset/rim width options. It is a good reference for aftermarket wheels which typically utilize lower than stock offset.

If the factory wheels are 8-inches wide with +55mm offset, the backspace works out to ~6.6-inches of backspace

If the factory wheels are 8.5-inches wide with +55mm offset, the backspace works out to 6.9-inches of backspace.
I thought we had it from @LEGEND that the Sasquatch 8.5" wheels were 30MM offset, but OK.

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