4 replies to this topic

[munter]

I think there are two types. Do they relate to the body type, i.e. split rear window or single piece window?
 

[Bill from NH]

The ones on the right were a factory option for a few years. They were cast (aluminum) and held on by the factory knock-off hub in the middle. They had a tendency to loosen up and fall off, so GM took them out of production.

 

I recall about 1980, I was behind a '70s red Vette roadster at a stop light in Londonderry. When it reached about 40 MPH the right rear tire came off and went 35-40' up in the air & rolled 200-300' away. The car came to a safe stop, but it was a good thing it wasn't going at highway speeds.

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[Dave Crevie]

The ones on the right in the picture were the optional turbine wheels. On the left are the Halibrand wheels usually used on the Grand Sports and other race only cars.

 

The wheels that fell off either had the knock-off not properly tightened, or the wheels and hubs improperly installed right-to-left. The knock-offs are rotationally sensitive. Properly installed, they automatically tighten during forward motion of the car. Reversed right to left will cause the knock-offs to loosen. The few race Vettes I worked on never had problems with wheels loosening. Also greasing the conical contact area of either the knock-off or wheel could make them loosen while driving. It is the friction between those surfaces that makes them tighten up; In the illustration below you can see that as the wheel rolls, the weight of the car keeps the contact between the wheel and knock-off at the bottom, and as the wheel rolls the knock-off is tightened because it essentially turns at a faster speed than the splined hub.

 

[Flathead]

I assume you are referring to which Revell issues had each of the shown inserts, in which case the ones on the left were issued with the earlier split window release; the others were with the single opening rear window slot cars. Rest of the chrome trim was different between the two issues also.

[munter]

Thanks, Flathead; you assumed correctly. Your information confirms what I suspected but couldn’t be sure of.

Much appreciated indeed.