usually radiator elements omni collinear was made by copper or brass tube and wire.
aluminum wheels cause a lot of probelms etcflat tires ,easy denting, poor performance get rid of them soon as possible
The bad thing about aluminum wheels, is they do not forgiveThe metal will fracture if you force bend it, it is designed to be tooled or heated and manipulated under pressureYour trusting your life to that rim, so don't take chances.
Aluminum tube is used for constructing bigger antennas such as for 2 meters or higher wavelength bandIn case of 2.4 Ghz antenna your wavelength is so short so that using a tube is mechanically impossibleYou have to use a flexible wire that will not easily brokenThis is why for these small antennas brass and copper are usually used.
