Bear in mind the ceramic ball bearing.

The everyday steel ball bearing has had competition from the ceramic bearing for a number of years, not least because ceramic ball bearings are considered to be more durable, light-weight and speedier. But these advantages come at a cost; ceramic ball bearings are complicated to manufacture and, therefore, more expensive than their steel counterparts. It might be then, that for the sake of economics, the standard steel bearing will suffice depending on what you need your bearing for. Below is a brief outline of the different types of ceramic bearings and what advantages they can offer.

Hybrid Ceramic Bearings

There are two types of ceramic bearing and the hybrid combines steel and ceramic. The inner and outer rings of the bearing consist of steel whilst the actual ball bearings inside are made of ceramic. The combination results in lower mass and higher stiffness compared with a pure steel bearing. A ceramic ball is about 40% less in mass than a steel ball of the same size. This results in reduced friction, less ball skidding and lower moment from gyro-spin which collectively results in a lower operating temperature for a given speed, and higher limiting speed for a given size. Stiffness of the bearing increases by up to 15-20% which makes hybrids especially useful in applications such as high speed machine tool spindles. Tool spindles are more accurate when using hybrid bearings as the increased stiffness improves strength and reduces the risk of deflecting under load.

Other advantages of the hybrid include a smooth surface finish and high hardness which mean they need less lubricant and are more forgiving of partial lubrication than steel bearings. Ceramic is also chemically inert so it won’t corrode, and nonconductive, preventing electrical pitting damage when used in electric motors or the like.

Full Ceramic Bearings

Full ceramic bearings are exactly what they sound like – bearings made entirely from ceramic. They are lighter than steel bearings, roll faster because the bearing races are smoother and are extremely durable. They’re also entirely chemically inert and nonconductive and they aren’t very sensitive to moisture. Most full ceramic bearings will need very little, if any lubrication.

Ceramic bearings are generally considered to be more efficient and preferable to steel bearings in a lot of contexts, but the problem at the moment is the price of these bearings which make going ceramic financially unviable for some. If you’re going to buy ball bearings on a small scale for a recreational activity like biking, skateboarding or roller skating you might want to invest in some ceramic bearings as you don’t need them on mass. In industry, many companies simply can’t afford to purchase ceramic, although it is hoped that the manufacturing process will improve in the next few years and make it cheaper to go ceramic.

Ceramic bearings aren’t always the best option however so you must be careful to assess each individual case before installing them. For example, in normal-speed applications where true fatigue spalling of a raceway tends to be the failure mode, the hybrid ceramic will significantly decrease life expectancy. In this instance a steel bearing would be the best bet. It’s always best to have a chat with the manufacturers of the bearing before you make a purchase so you make an informed decision.