the seal slips on the outer race - why this design?

[hcoles]

Application - Rear wheel bearing 1989 Porsche 911
Original SKF bearing was a dual row angle contact ball bearing. PN 305988 42mmx80mmx42mm The seal slips on the inner race.

I got a "replacement" FAG 527243CA - the seal slips on the OUTER race. In other words the seal is moving. My question is why do they do this? What application indicates having the seal move with the inner race?

In this application debris can build in the tight area next to the moving seal - therefore I think this is not a good application of the outer slip type seal.

Please comment if you can.
Thanks,
-Henry

 

[unclesyd]

It looks as though the FAG seal will take a little more internal pressure than the type D seal shown at the Dynaroll
site. This could be a decided advantage on certain gear boxes.
This design would also tend to prevent debris from contacting the edge of the lip seal, not so in the D type seal. This would do the same a the add on shield we used to prevent debris from contacting the seal lip and migrating to the rubbing surface.

 

[hcoles]

Russell,
if it wasn't for the debris/possible rubbing concern you are probably correct... my concerns could be not an issue but at least I would say it was reasonable to question it expecially since it is different than OEM. There is probably a chance the FAG is superior.. but I don't know the other specs. on it like ball tolerance/what type of grease/etc.

Since the company will take back 2 FAG's (one was installed and they know that) I'm going that route and installing the conventional "D" seal SKF.

-Henry