There are a number of variations of the wheel bearing. Basically, as a rule of thumb, ball-bearings are used when the load is low and if there is enough space, needle- or roller-bearings are for when there is a higher wheel load and only little space. At the bottom left of picture 6, you can see the adjustable tapered roller bearing, which has already been described here. Next to it is the one for the driven (front-) axle, which is decribed here. Now, one could be of the opinion that a lot more variations are not possible. Far from it, if e.g., you consider the price of repairs.
Some manufacturers, thus also the customers, try to save money when buying new parts. If the supplier is also trying to save money, the situation arises which is shown in picture 4. In this case, the wheel bearing and the brake-disc form an inseparable unit. This means, that if the wheel bearing is worn out, the brake-disc must also be replaced. Now, one could possibly replace the wheel bearing on one side only, not however, the brake-disc only on one side. Thus, bearings and discs on both sides. What's even worse, is that this also applies to the more frequent wearing out of the brake discs as well!
Just imagine, new brake-discs for over € 500. This recommendation cannot be over-emphasized: Before buying a new car, go to the spares department and find out what the prices are like for a few typical replacement parts. One can also get information from the respective forums on the internet.
Indeed, we're not quite finished with interim solutions. In picture 5 you can see a snap-connection between the brake-disc and the wheel bearing. You need special tools to be able to release this in such a way that it can be properly seated again. As with a lot of repair jobs, this is an example of how a single repair job can neither be reasonably nor expertly carried out. By the way, the workshops are presented with attractive offers from the suppliers, to automatically replace the wheel bearings on both sides (picture 6). Most do-it-yourself mechanics are probably not aware of this and would find it difficult to take advantage of such opportunities anyhow. 09/12