I have often wondered why there is a spacer between the two roller bearings in a Mini hub. is it a "left over" because one is needed when ball-races are used ?
On prewar front stub axles there was a substantial inner roller-race and a smaller outer one. The nut holding it all together was tightened until there was no play, and then backed off sufficiently to insert a split pin. No spacer between the bearings !
One way to put this is these wheel bearings work back to front to 'conventional' wheel bearings.
On a 'conventional' set it, the axle is 'dead' and the hub spins around it, so the pre-load (or play) can easily be set with the nut.
On all FWD Hubs, this is reversed. The Axle is 'live' and the Hub is 'dead'. Additionally, the Live Axle also has to lock to it the Drive Flange and hold it in tight alignment, so the nut here, must be done tight. If there was no spacer, the bearing would simply be overloaded and locked.
Thank you. One less thing to ponder about in the bath.
ahhh but the rear?
Yeah, I have no answer on that only to make them stuff up proof.
In fact, thinking more about this, if anything, the way the Mini is done, with a spacer here, that pre-sets the pre-load, as set by the bearing manufacturer's is a better way of doing business, rather than have no spacer and rely on mechanics, some of who would do it in accordance with the recommendations and others who think they know better.
Many modern cars actually now use Hub Units in which, you don't even see the bearing or grease it. These Hub Units are in theory like our wheel bearing assemblies, only taken to the ext level or 2.
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