What is Out-Gassing? (Clear Coat Bubbles)
Tiny air pockets naturally occur in all cast aluminum wheels.
During the curing process, trapped air can escape through the clear coat, leaving small bubbles or pinholes.
This is a normal characteristic of cast wheels and is accepted throughout the wheel industry, including OEM manufacturers like Toyota.
Where do they show up?
Typically, only in cast wheels.
Most noticeable on machined, clear-coated finishes because the clear coat highlights imperfections.
Rarely seen on forged wheels.
When should a wheel be rejected?
(Zone A = Wheel Face, Zone B = Spoke Windows)
Reject the wheel only if one or more of the following applies: Zone A (Wheel Face)
A bubble is larger than 1.0 mm
There are more than 5 bubbles between 0.5 mm and 1.0 mm
There are more than 8 bubbles smaller than 0.5 mm within a 25 × 25 mm area (they are densely clustered)
Reject the wheel only if one or more of the following applies: Zone B (Spoke Windows)
A bubble is larger than 1.5 mm
There is more than 1 bubble per window
There are more than 10 bubbles smaller than 0.5 mm within a 25 × 25 mm area (they are densely clustered)
If none of these conditions exist, the wheel meets Wheel Pros' finish standards.