Kaban

Is it from the inner barrel of the wheel like figure 1 or from the outer edge of the rim like figure 2?

Kaban

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RacerLex

I believe it's measured like your first pic. Check out this link:

http://www.tirerack.com/wheels/tech/...urrentpage=106

SoCalSC4

It's always measured "inner bead-seat to inner bead-seat" like figure 1

Therefore, a 10" wide wheel will actually meaure 11" overall outside-to-outside)
Tire manufacturers are concerned with how the tire sits INSIDE the rim flanges.

Kaban

Thanks for the good explaination guys, and link.

I thought I was going delusion when my wheel measured 11+" instead of 10".