Tiffen M1/M2 gimbal pan bearing friction: PRO gimbal bearing compatibility, lubrication best practice, and bearing precision differences.

2020From a Facebook group: The Steadicam Group

The M1 and M2 gimbals share the same bearing size as the PRO gimbal, making PRO pan bearings a direct replacement; operators reported noticeably quieter, smoother operation, better lock-offs, and elimination of fishtailing after the swap.
PRO bearings use a white nylon cage with precision spacers and tighter tolerances, while Tiffen bearings have a metal cage; some new M2 units exhibited rough noise and squeaking during dynamic balancing.
The Tiffen manual recommends 5–10 drops of oil, which appears to be excess; PRO recommends dry or at most one drop; one operator achieved marked improvement by degreasing and applying a single drop.
Spin-down tests on the same M2 gimbal showed the Tiffen bearing coasting approximately 1:00–1:04 minutes after an identical impulse, while the PRO bearing coasted 1:14–1:18 minutes.
According to the PRO gimbal designer, the large bearing diameter (chosen for stiffness and centering) amplifies any friction; the PRO bearing was selected for its expensive, high-precision materials and specific preload to minimize breakaway torque at the start and end of pans, as high-speed capability is irrelevant to the task; hybrid or ceramic balls, cage material, and exact bore and grip-insert tolerances are critical.
Early Model III gimbals used a large threaded nut to preload the pan bearing; early and later M1 series units are reported to perform noticeably differently; replacement M1 pan bearings cost approximately 350 USD when available.

Bearing performance depends on gimbal model generation and preload history.
Lubrication practice varies between manufacturers and may differ from printed guidance.