[jeffschevelle]

I have concluded that the rivets on the Z16 wheel were really just a workaround to make two wheel component pieces work together that were not really designed to be used together.

The different Z16 outer rim (versus a regular drum brake 14x6 outer rim) had to be used in order for a wheel with the Chevelle wheel offset to clear the 11" rear brake drums. A 65-67 Impala C-code 14x6 has the wheel center set deeper in the rim (so the outer rim is further out toward the side of the car), so it cleared the 11" rear brake drums no problem. But If you try to bolt a 66 Chevelle SS wheel (which is the same offset as a Z16 wheel) on a Z16 rear axle, it will not go all the way on before the wheel is wedged onto the brake drum. The "disc brake" style out rim was necessary to provide the additional clearance for the rear drum.

But that outer rim and the regular 65-67 Kelsey Hayes center wheel piece do not have enough contact for a full weld like you find on a regular pre-68 14x6 wheel. Notice in the pics how the "legs" of the center piece protrude out into the air where the outer rim bends outward. There is very little contact patch between the two pieces there. So I think the rivets were the only way to achieve the attachment strength required.

So that fixed the problem at the rear, but the rivets then created another problem at the front. They hit a regular 11" front brake drum before the wheel is all the way on! So that then led to the special Z16 front brake drums, which have an area machined away so that the rivets clear the drum.

Ad hoc engineering at its best!!