Bicycle bottom bracket in different versions
Hardly any part of the bike is for many bikers as inconspicuous and mysterious as the bicycle bottom bracket. Here, the bottom bracket, as the bottom bracket is often called, withstand incredible loads. Among the driving forces acting on the bicycle inner bearing, come even the burden of the driver itself. Fortunately, the days when broken and broken axles were the order of the day are fortunately over.
Due to the permanent further development of the bicycle bottom bracket, you can choose today from a variety of different designs. Amongst other things, the modern standards include multi-toothed roller bearings such as the Octalink and BB, BSA square internal bearings and the Hollowtech II ISIS bearing.
Different standards for different applications
Unfortunately, the different standards that have developed over the years are not compatible. When replacing individual parts, such as the crank, you must orientate yourself on the existing bottom bracket. Often the replacement of the complete bearing with the cranks is less expensive than the purchase of parts.
When buying a bicycle inner bearing, keep a few things in mind. So you have to pay attention to the case widths, which are different from bike to bike. In addition, the thread type and the question of whether pressed or screwed bearing shells play a major role. The data sheet of your bike gives you information about which standard or which bottom bracket you can fit on the bike.
Square bottom bracket
The square bottom bracket is especially often used on older bikes. Until around 2000, the bottom bracket with intrigued square axle was standard, for racing bikes mountain bikes and also all other wheels.
Multi-tooth bottom bracket
As with the square bottom bracket, the axle is integrated in the bottom bracket of the multi-tooth bearing. The crank is placed here on the left as on the right side of the axle. The socket for the crank is designed as a splined tooth, hence the name of this bottom bracket standard.
Hollow axes bottom bracket
In contrast to the splined or square bottom bracket, no axle is permanently integrated in this bottom bracket type. This standard can be seen today on most mountain bikes, cross bikes or city bikes. The axis of the crank is guided here in through the cavity of the inner bearing. It should be noted here which mounting width and housing size is required. You also have to pay attention to the mounting size of your crank.