39412-20629 Timken Aircraft Wheel Bearing Cup, Class 2, Code 629 | McFarlane Aviation 3941220629

Please confirm the 39412-20629 bearing cup’s compatibility with your aircraft using this document:

• Timken Wheel to Seal Kit and Bearing Cross Reference section of McFarlane Aviation catalog

Because Timken uses the same part number for both the automotive and aviation versions of these bearings, many people mistakenly use the lower quality automotive bearings in their airplane. It is critical that the FAA-PMA Class 2 version be used for aircraft applications for two reasons:

• They are a higher class of bearing with tighter tolerance and have been subjected to more stringent quality control procedures. Due to the smaller diameter of aircraft wheels, at a given ground speed the bearings rotate at a much higher RPM and require the tighter tolerances to prevent premature failure.
• Example: At a 70 mph touchdown speed (equivalent to highway speed of a car), a typical 17 inch diameter airplane tire is rotating at 1384 RPM, whereas a typical 27 inch car tire is only rotating at 871 RPM. So even though the aircraft bearing is only subject to intermittent use, some of the performance demands are much higher than a typical automotive application.

It is a violation of FAA regulations to use non-approved automotive bearings on certified aircraft.

Product Details:

• Class 2 aviation grade FAA-PMA approved bearing cup
• For Goodyear, Cleveland, and McCauley wheels
• Manufactured by The Timken Company