Odd Wheel mounting flange?

[Kansas T]

I got a set of 4 15x8.5 Vector wheels, and one has an odd mounting flange on the back side. Everything else looks the same. The wheel on the left is like all the others, the wheel on the right has a recessed mouning flange.

(the brown center is recessed about a 1/4 inch into the wheel)

I was told that they came off of a '78 El Camino. I've never see a wheel with a mounting surface like this. What is it for? I'm afraid if I try to use it I wont be able to get it tight without damaging the wheel or the hub. Does it require some kind of spacer? Anybody else using a wheel with this kind of mounting flange?

 

[Kansas T]

ttt

 

[Kansas T]

Anybody seen this??

 

[ChrisCairns]

Originally posted by Kansas T
Anybody seen this??

Those are nice looking wheels from the front.

Did you try getting out the ole micrometer and measuring the thickness of the center section on each wheel. It almost looks as if the one wheel has been machined to remove that "star" mounting surface like on the untouched wheel.

 

[Kansas T]

I didn't get a micrometer out, but it looks to me like it was cast that way.

 

[Kansas T]

Thought I'd try this again, maybe somebody knows. Another local TR owner found a set of wheels with the same backs as this pic: http://home.swbell.net/gjaws/whls4.jpg
Anybody else seen this? What can be done to make the wheel work on a TR?