Does any one know what the wheels on a 3rd gen are made from, specifically what grade of forged? aluminum? Any help would be greatly appreciated.

 

they are casted out of aluminum i believe

obviously not very good grade because at under 70k miles one of mine had cracked all the way through the spoke by itself while just driving. the 93 wheels are a bit thinner than the 94s and some crack.

 

Not sure what aluminum alloy, but they are squeeze cast and unusually strong for their weight.

There were some defective castings initially that cracked, but you would be hard pressed to find a better quality wheel anywhere even today. I think they were made by Enkei - but not sure.

I'm still amazed that they put this quality of wheel on as a stock item 11 years ago.

 

The spare is made by enkei.

 

Probably 356 alloy - curious as to why you need to know?

 

Actually the original FD wheels were not defective in casting, they were under-designed. I saw in one of the RX-7 books a pic from the back of the wheel and after seeing it you can easily identify the "weak" type. The redesigned wheel has more material where the spokes meet the hub. I wish I could find the same pic online but I cannot.

 

RX-7 performance handbook by Mike Ancas shows the two types of FD wheels. There is also a thread in suspension / wheels / tires which has pics of each type.

 

Squeeze-cast or Pressure-cast aluminum. They maintain a pressure during cooling to prevent air pockets from forming inside the metal, thus making it much stronger.

Differences in casting. Easiest way to tell the difference is on the backside of the wheel where the wheel touches the rotor hub. The thin one has 5 nearly square voids between the bolt holes. The thick one has 5 bell shaped voids between bolt holes. I have a picture, but not sure I can post it.

Tim

 

Hope this works.

Tim

 

I was thinking of making skinny's out of 2 of the spare's I have for drag racing. The guy that would do the welding wanted to know the alloy, I suppose for the filler rod. I'm not sure I want to take this project on yet though.

Tim, Thanks for the pic, you can see it quite clearly, there seems to be a big difference between them.

 

That's it! Thanks Tim.

 

Ahh, makes sense.