This post should help you out.

 

I remembered talking about this before so I searched for all my posts under my profile. When I found the thread I copied the address and went to the "post a reply" (not the blank on the bottom) and hit the HTTP button. I typed "This post" into the blank then hit OK and then pasted the link and hit OK. Easy as pie.

 

All alloys are mostly aluminum with differing percentages of other metals. The key is going with as light a mixture as possible that works with the geometry of the wheel to give enough strength.

I'll go out on a limb and say "light alloy" is nearly the same stuff as the rest with a little marketing swing. It probably is a pretty light wheel though if they make the "light alloy" claim.

Cast wheels (~90% of all of 'em) are just liquified alloy poured into a mold. Standard is "gravity" cast - which means no additional pressure is applied to decrease the porosity of the metal. This is the least expensive method.

Then there are various methods of pressure casting. It is a bit more involved and usually ends up with a stonger alloy because of less porosity. These are a bit more expensive generally and lighter weight.

Spun wheels (pretty rare right now) are usually cast normally but look like just the face of a wheel with a thick ring around the outside. Then a machine spins the wheel casting while another wheel(s) forces the material into shape. This further decreases porosity and adds strength/loses weight.

Forged is the buzzword right now because it offers about the best strength to weight ratio per unit of metal. Theis is when a chunk of aluminum alloy is smashed into a mold using thousands of pounds of force. These are generally the expensive wheels but are very highly regarded.

Bottom line - if acceleration/deceleration is highly important to you, you'll get your monies worth out of a light wheel. Just make sure you're getting a reputable wheel from a reputable company because regardless of manufacturing method, there are plenty of poorly designed and manufactured wheels out there with great marketing behind them.

The quality of the wheel starts with the spoke design and how it maximizes efficiency with the alloy mixture/manufacturing process used. It ends with the finishing/coating process and the specs that match it correctly with your car.