Billet Aluminum
Billet wheels are very similar to forged as far as strength and weight but are not as common due to the enormous amount of waste created to make a single wheel. If you're after exotic designs, logos or internal patterns for your wheels, billet is your only option. The wheel starts as a solid hunk of aluminum and can be crafted into whatever your imagination can come up with, but it also comes at a price.
Billet wheels gained popularity in the chopper world. |  |
Forged Aluminum
The most common type of aftermarket wheel is made of forged aluminum because of its high strength-to-weight ratio and relatively low cost. The forged wheel's life starts as a rim blank that is then machined to the desired size and shape by a CNC mill. Most forged aluminum wheels fall in the middleweight class, although there are a few out there that sneak into the heavyweight category due to bolt-on bling and more intricate designs.
 | 
Many performance focused sportbikes use cost effective forged aluminum. |
Carbon Fiber
Resting comfortably alone as the lightest wheels available are carbon-fiber wheels. Carbon fiber is very strong and extremely lightweight, but is also the hardest to produce-which makes them the most expensive of the bunch. Despite the significant weight savings over any other aftermarket wheel, they are comparative in strength but dramatically more in cost.
 | 
Kent Stotz's 500-plus horsepower racerruns carbon fiber hoops. |
Conclusion:
An aftermarket wheel's styling enhancements alone will change your bike's attitude, and a performance- focused wheel will bring a smile to your face as well. Upgrades aren't cheap. But for knockout looks and a better-handling motorcycle consider it money well spent.