We answer a lot of mail regarding aluminum parts and alloy parts. There are some who feel that alloy parts are not aluminum or that alloy is weaker and heavier. The terms are quite commonly used, although technically incorrect, interchangeably. Aluminum in its pure form is highly ductile. This means it is easily shaped by bending. Aluminum is alloyed with other elements such as copper, magnesium, silicon, manganese, and zinc. When alloyed, the mechanical strength of aluminum is enhanced.

The Aluminum Association has determined standard alloys. These alloys are designated using a four digit number such as 6061 or 7075 followed by a temper designation such as T3 or T6. T3 means that the alloy was solution heat treated, cold worked, and then naturally aged (age hardened). A solution heat treatment followed by artificial aging is indicated by T6. The "most pure" aluminum alloy commercially available is 1100. This is used in low grade cooking utensils.

The alloys used to make GPM parts and accessories are 6061-T6 for suspension components, and 7075-T6 for chassis plates and other strength critical parts.