Sealed rear hub bearings

[philthehill]

In the latest edition (March/April) of Minor Matters, Technical Tips there is a recommendation by Andrew Bywater for the use of sealed, packed for life rear hub wheel bearings.
I would advise against using a sealed bearing for the following reasons - if the sealed bearing is fitted the standard oil seal will have no access to lubrication for the seal lip and there will be no provision for the axle oil to cool the seal. If there is no oil around the standard seal it will fail.
It is no good filling the inner cup of the seal with grease as that is not a sustainable solution.
If only sealed bearings are available the seals can be removed to make a open bearing which will allow the rear axle oil access to the lip seal.

[svenedin]

I haven't received my copy of Minor Matters yet. What was the justification for using sealed bearing? The Minor suppliers e.g ESM do not sell sealed rear or front bearings.

Stephen

[philthehill]

As I read it the justification for fitting the sealed bearing was the additional protection given against oil leaking onto the brake linings.
Unfortunately - fitting the factory hub seal or a double lip seal is mentioned in the article but it does not recognise what will happen to the seal if it does not have lubrication i.e. a dry neoprene seal on a dry axle tube will overheat and fail.
If a sealed for life bearing is to be fitted I would suggest that the original factory seal is removed/omitted and the outer face of the bearing sealed into the hub casing to prevent any oil progressing past the bearing outer face and the inner face of the hub.

[Mervin]

"sealed, packed for life rear hub wheel bearings."
I've always been very skeptical of that statement, not only for bearings.
They never define "life". A bearing that can be further lubricated/greased, e.g. by axle oil, will have a far longer life than a "sealed for life" bearing.
Possibly a poor example, but TomTom declare their navigation devices (some) have lifetime map updates. Then after a time declare the device has reached end of life and no further updates/support.