Main bearings seal failure question

[aeolian]

Just being curious .
Is any of the two main bearing oil seals prone to fail easier or faster than the other and why is that ?

The flywheel-side seal is subject to
air flow debris ,while the clutch-side one may be subject to bar oil and wood chips .

Any ideas ?

 

[Stem]

clutch/PTO side is subject to more heat than the flywheel side. running chain too tight, dull chain, clutch heat etc are all factors for seal failure.

 

[Wonkydonkey]

All what Rob said
and the bearings fail more on the pto side as well which help the seal to fail at the same time.