Hollow Technology wheels
 

How do you tell if they are hollow or not, I've heard the spokes are flat on the back and the steel valve stems give it away. Mine are 18" X 8.5 & 10. Any help appreciated...I'm trying to sell them. Also any Idea what they are worth?? Good shape, not great.
TIA
Coz :p

Yes, that is how you can tell the difference but if your fronts are 8.5" wide, they are not Porsche wheels. The factory wheels where 8" and 10".

You could weigh them.

Check out this previous rennlist thread:

Topic: Performance differences between hollow spoke and non-hollow spoke...

My 17" Cups have a part number on the back of the rim; I'm sure the 18" should as well. I also recall that someone in previous posts (archive search) has posted the partnumbers for the solid and hollow rims.
Edward