With the exception of one product, the entire line of Kogel Bearings runs on hybrid ceramic bearings. Hybrid means that the balls are made of a ceramic material, but the races or rings are made of a hardened steel. This is different from a full ceramic bearing, which would have both the balls and the races made of ceramics.
Two types of ceramic materials
There are two materials that are common for use on bikes: Silicon Nitride, a dark grey material and Zirconium, a bone colored material. Kogel makes all balls out of Silicon Nitride because it is harder than Zirconium, but we have seen both materials used for balls. The latter is slightly more flexible and therefore more suited for the rings. Silicon Nitride would be too brittle and could break under pressure.
- Silicon Nitride is hard and can be polished smoother than any metal. This makes it perfect for ball bearings.
The first major problem with full ceramic bearings is that the installation is quite tricky. The bearings are fragile and they crack easily. Think of turning the handles on your press a quarter turn too far and you’re fishing broken parts out of your frame. In the world of Kogel, it means we can install bearings in a bottom bracket in our assembly, but there is no control on how the bottom bracket will be installed in the bike. Unfortunately we still have customers that think a hammer and a wood block are OK tools to work on expensive bikes.
Hitting a pothole
Full ceramic wheel bearings would be an amazing way to reduce friction in hubs. After all, since there are no chance for parts to oxidize, there is also no need for grease. In most bearings, the grease is the main source of friction.
The problem here is that wheels take hard impacts from potholes. A hard jolt that makes your hands hurt on the handle bars also sends a huge shock through the hub bearings and could crack the races. Since Kogel Bearings is a US based company, I would rather not be involved in a law suit with someone that had his or her wheel freeze up because of a jammed bearing.
- Seriously, Kogel Bearings has zero interest in putting one of our customers in a situation where their front wheel stops on a dime due to a broken bearing ring.
One exception to the rule
The one product that we do offer with a full ceramic bearing is the ‘Not for Instagram’ pulley set. Derailleur pulleys do not take any impacts, we can install the bearings in our factory, perfect! Since the bearings do not contain any grease, they seem to spin forever.
I hope this article gave you some insights in the choices we need to make to bring you the best and above all, safe ball bearing products.