Front Wheel Bearings

Article courtesy of Steve Koen

Bearings fail for many different reasons. The least often reason is just plain worn out - in fact, very few bearings get to run their entire life and expire from being worn out. The more frequent reasons for bearing failures include over-loading, dirty or incorrect lubrication which includes too much or too little grease, or if the bearing fails after a very short time - then the reason is very frequently, just plain poor fitting. Bearing marketing groups world wide make millions of A$ from training people how to fit bearings correctly. However, they also rake in hundreds of millions of A$ from bearing failures attributable to poor fitting procedures.

The rolling elements in any rolling bearing must have a smooth race over which to run. As Colin suggests, drive the angular contact wheel bearings of our Sprite's front hubs into place by using another outer race (reduced outside diameter to get them out easily) to push the outer race of the bearing into place. If you can, a press is logically the better alternative because a push is preferable to an impact. But if you press, or gently tap the outer race into place, then there is no way that the rolling elements can impact the inner or outer race - known as "brinelling" - and therefore shortening the service life of the bearings. The problem occurs when you wish to remove the bearings from the hub, as the easy way to get to the bearings is to push the inner race which then forces the rolling elements against the outer race, thereby pushing the complete bearing out of the hub. Since this has the potential for damage to the inner race, the rolling elements and also the outer race, it usually means that the bearings can be questionable for re-fitting. Unless the removal procedure has caused no brinelling of either raceway or the rolling elements.

So put it simply - use Colin's tried and proven methods, preferably with a press, or just tapping the outer race without striking the elements or the inner race. Forcing the inner race into the hub can cause it to separate from the outer race, and it can be difficult to fit back in properly without damage ensuing. Use proper procedures and you should have satisfactory service life.

Oh yes, and pack decent grease into the bearing prior to fitting. And keep the entire operation perfectly clean. It doesn't take much grit to start a bearing failure.