Meaning of offset on Toyota rims (1 Viewer)

[Living in the Past]

I have aluminum alloys for the pre-Tacoma, 2nd gen 4Runner and 91/92 land Cruiser. Some have no marked offset, some have 8MM, then the LC are marked 10MM. Think the no offset are the oldest. 8MM are mini truck/4Runner. My guess is the 8MM and 10MM are based off the original non marked alloys. My question is which way is the offset. I roughly measured the LC alloy at 4.25". For what ever reason the LC uses a tapered lug nut while mini truck/4Runner use the shank style.

 

[Living in the Past]

Thought this would be a easy question? Was able get to a wheel with no offset and measure it. Offset was just over 4 1/2". 10 MM is around 3/8" which tells me the offset cast into the wheel is less backspacing not more. 1" wheeler spacers should work with 80 series wheels on my FJ62 but probably need 1 1/2" to run the no offset rims. Probably pick up some 1" wheel spacers and see what is the greatest backspacing will work to keep the wheel inside the wheel well as much as possible.

 

[studawg]

Was able get to a wheel with no offset and measure it. Offset was just over 4 1/2".

You mean "backspace was just over 4 1/2"?

Another way of looking at it is on a 15x8 wheel, for example, with 4.5" of backspace, you know the offset is going to be zero because thats right in the middle of a 15x8, which are actually 9" wide edge to edge, (bead to bead is 8"). A 15x8 with 4" backspace is going to have a negative offset of about 12.5 mm.

 

[cruiserpilot]

New rules for old school thinking. Metric measurements. The offset or backspace is not the same anymore for single vehicle. So
with the variation of wheel widths, and also depending on diameter there is different offsets.
This is the most accurate I've found, and for the poor souls who are stuck in an SAE world it gets tougher.
You have to learn how to convert metric millimeters into inches.
Look below as example the 9" wide rim, needing 3.5" BS - you would look for a wheel with a -38 mm offset.
Clear as MUD?
And since I just reread your original post, offset is always measured from the rear mounting face of the wheel.

 

[studawg]

You have to learn how to convert metric millimeters into inches.
Look below as example the 9" wide rim, needing 3.5" BS - you would look for a wheel with a -38 mm offset.

View attachment 1337774

Yes that table shows exactly what I just explained.

1" = 25 mm

A 9" wide rim with 3.5" of BS can have no other offset besides -38mm. Because a wheel listed as 9" is actually 10" wide, half of that is 5", 5 minus 3.5" is 1.5", and 1.5" converted to millimeters is 38.

 

[cruiserpilot]

The chart saves on the math. Its really handy when pouring over hundreds of rims on websites looking for
wheels.