BMW HRE FF04 Wheel Fitment Guide
What are HRE Flow Form Wheels?
HRE Performance Wheels' all new line of FlowForm wheels combines the strength and durability of a forged wheel,
at a price point that is near standard OEM cast wheels.
The process begins with a pressure-cast perform, where it is then rapidly cooled. This quick cooling of the metal right after heating (sometimes referred to as quenching) enhances the elastic strength and durability by increasing the metals density
The strengthened pre-form (Fig A), is then pulled from the mold and placed into the flow-forming machine, (Fig B) which operates in a manner similar to a potters' wheel. This process stretches the barrel downward, causing the metal to ""flow"" into the correct ""form"", hence the name, and this process ultimately gives the wheel its final shape (Fig C).
This ""stretching"" process changes the internal grain structure of the aluminum (much like the direction of the grain makes a difference in wood), making it stronger, lighter and more precise than a non-flow-formed barrel, resulting in forged aluminum-like strength.