Anodized aluminum parts are common in the bicycle world. Anodize is a very thin coating on the aluminum to protect and/or beautify the parts. The most common anodize for machined parts is Type II or “Color Anodize”. This is the pretty coating on the attractive and colorful parts. Type I is also used, but more often on cast parts. Then there’s Type III (aka “Hardcoat” or “True Hard”) which is used more in military and industrial settings. Type III is called “Hard” because the surface is much harder and more wear resistant than the Type I or Type II. It’s more common for industrial and military because it does not color well, and is generally not as attractive.
Why does it matter?
At WickWerks we use the “Hardcoat” or “True Hard” for it’s amazing abrasion and wear resistance. It is a little more expensive, and it does not have color options (other than black), but it provides a superior level of protection intended to extend the life of the WickWerks chainrings. Read the full tech post about anodize, here.