Wheel questions, I suck at figuring offset

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I am a fan of the newer TRD Pro wheels from the 2021 Tacoma. They are available in a 16" format but I am not sure if they will be a good fit for the Land Cruiser. Can someone please chime in that knows something about offset?

I am running the stock 94 Land Cruiser alloy wheels with a 315/75-16 now.

TRD wheel.jpg


TRD wheel specs.jpg
 
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Can’t remember if the OEM alloys are 4” or 4.5” backspacing... so here’s 2 answers LOL

If 4” backspace, then the outer lip of the wheels will sit 1” closer to the body. Inner lip with stay the same.

if 4.5” backspace, then the outer lip of the wheels will sit 1/2” closer to the body. Inner lip with sit 1/2” further from the body (more inner clearance).
 

on the rocks

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Tacoma's and 4-runners run a high positive offset, google it. The majority of the 80's here run 4-runner and Tacoma wheels resulting in a typical 1.5" spacer or the wheels are too far inward. That's why most here have to run the spacers. Unfortunately not a lot of options on correct wheels for the 80, still. Maybe the 300 series coming with a 6 bolt will change this but it's likely they will run a high offset as well, must have something to do with IFS and pushing everything out.
 

LandLocked93

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^^^This. Most 6-lug/TRD wheels released in the last decade or more require significant spacing to fit right on an 80.
Just for reference, I went with -12mm offset and 4.25" backspace on a set of Vision 84 D-hole (Procomp51-like) wheels.
On 285/75 E-rate the outside edge of the tread is a half-inch inside the fender flare extension, with the sidewall bulge being equal to the flare. Pretty much perfect for my tastes. (can't stand debris flinging up on the sides and windshield, so opted to keep them tucked under).
 
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Here's the easiest way that I have finally figured out how to determine offset vs backspacing. First of all, they are two different measurements even though people will use them interchangeably. Yes, they CAN overlap and coincide with each other, but this makes it easier to imagine.

Offset is the measurement of the mounting flange surface(rim to hub) from the CENTER of the rim. Can be positive or negative. Usually measured in mm +/-
- Positive offset moves the mounting flange toward the OUTSIDE lip which makes the rim sit closer to the frame of the vehicle.​
- Negative offset moves the mounting flange toward the INSIDE lip which makes the rim sit further away from the frame of the vehicle.​
Backspacing is the measurement from the mounting flange surface(rim to hub) to the INSIDE lip of the rim. Usually measured in inches.
- Changes with rim width assuming your offset is ZERO.​

Backspacing:
- Examples -
- An 8" rim will be a total of 9" wide when adding inside/outside rim surfaces. (1/2" + 8" + 1/2").​
- With ZERO offset (no deviation of the mounting flange from center) the BACKSPACING will be 4 1/2" (half of the overall width of 9")​
- A 9" rim will be a total of 10" wide when adding inside/outside rim surfaces. (1/2" + 9" + 1/2").​
- With ZERO offset (no deviation of the mounting flange from center) the BACKSPACING will be 5" (half of the overall width of 10")​
Offset:
- An 8" rim will be a total of 9" wide when adding inside/outside rim surfaces. (1/2" + 8" + 1/2").​
- With -12mm offset (let's call it -1/2") the BACKSPACING will now be 4"​
- An 8" rim will be a total of 9" wide when adding inside/outside rim surfaces. (1/2" + 8" + 1/2").​
- With +12mm offset (let's call it +1/2") the BACKSPACING will now be 5"​
- A 9" rim will be a total of 10" wide when adding inside/outside rim surfaces. (1/2" + 9" + 1/2").​
- With -12mm offset (let's call it -1/2") the BACKSPACING will now be 4 1/2"​
You can follow that math below using this chart and you can see how they are different measurements, but still are connected.
1617633961959.png

Here's a link to a site where you can play with different rim/tire/offset/backspacing options to see how they change.

 
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@OffRoadScott

To use my explanation and the wheels you're looking at here are the numbers:
- Factory rims 8" wide (9" wide including both flanges) with ZERO offset, backspacing will be 4 1/2"​
- TRD 7" rim (8" wide total including both flanges) with +13mm offset (again, let's call that 1/2" or so) backspacing will be 4 1/2"​
These two rims in theory will have the same INSIDE rim lip distance to the frame, but the TRD wheel, due to it being a more narrow rim overall, will look like it is "sunken into the wheel well". Spacers will bring the wheel further away from the center of the vehicle effectively "filling out the wheel well". (- *if the TRD rim had a ZERO offset, the backspacing would be 4" and would be the same as adding 1/2" spacers.)
 

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