In spite of not being in sight, the bearings are a fundamental component for the proper functioning of the bicycle since the bicycle’s performance depends largely on them.
They are found in different key parts of it: in the direction, the bushings, the bottom bracket, suspension pivots … and have the function of allowing the movement of rotation between two parts joined by rolling, unlike the bushing friction that they do by sliding contact surfaces. This allows a smoother turn and with less friction so they can turn faster. However, the smaller existing contact surface means that they cannot withstand such high loads.
These characteristics mean that we find different types of bearings for the different turning points that we can find in the bicycle since the functional requirements are quite different: high speed of rotation in the axles of the wheels, high loads and reduced turns in the articulations of the suspension system, axial load direction in the direction …
ISB steel bearings:
Steel bearings are the most common on bicycles since they are very durable as long as proper cleaning and good lubrication is maintained. They have radially located steel balls inside the tracks or raceways.
They are really very effective, and significantly reduce the friction in the turn compared to other systems such as bushes.
These bearings are usually sealed in different ways: the RS / RZ, which is the new generation of ISB Sport rubber seal for bicycle; or the usual ones with rubber (2RS) or metal covers (the ZZ type), the latter made of the same steel as the rest of the bearing.
If the reference includes the suffix SS, it indicates that both the balls and the steel are made of stainless steel type AISI 420.
RVMax ISB bearings:
For the area of the suspension, some suitable bearings have been developed to support certain load levels, without this implying a significant increase in weight or size. These are the VMax series bearings that have been specially designed for the entire joint of the main swingarm, linkage and shock absorber, to withstand reduced turns.
Its main feature lies in its special “full ball” design, which consists in the suppression of the usual inner cage that separates the balls and allows the insertion of as many balls as possible. The tracks of its rings are deeper in order to obtain a greater lateral support for the torsion and the multiple forces associated with the pivots of the bicycle, especially for the mountain.
This series of VMax bearings have up to 35% -40% more load capacity than standard ISB series steel bearings. Its sealing by rubber caps on each side, identified as “2RS”, they provide maximum protection against external pollutants and maintain the original lubrication.
ISB ceramic bearings:
We call ceramic bearings those bearings in which the usual steel used in its manufacture is replaced by a ceramic material either in the balls for hybrid bearings or in both the balls and the tracks for the full ceramic.
Normally located on the front and rear wheels, ceramic bearings are in a position to provide a remarkable improvement in efficiency, maximizing the performance of the bicycle itself.
Its main advantages over standard bearings are, on the one hand, a higher operating speed and on the other, a longer service life under the same conditions of use. Its low coefficient of friction (up to 10 times less than in steel bearings) due to the lightness of the balls, provides extremely smooth operation generating less heating, less wear and therefore prolonging its durability.
Ceramic balls, being lighter, generate a lower centrifugal force that results in less friction and allows the bearings to move faster since they require less energy to maintain speed. The ceramic is very resistant to oxidation, so its useful life is also superior to that of steel bearings. Ceramic balls retain their rolling characteristics for a longer time and do not have the same maintenance need as steel ones, functioning properly even with a very small amount of lubricating oil.
The higher degree of hardness of this type of bearings requires a more demanding surface finish than in steel and in the case of hybrids, ceramic balls much smoother and more resistant, they are microscopically polishing the steel tracks improving their finish and producing a smoother roll. Hence the expression that ceramic balls “clean” the tracks and require a period of shooting.
In the series of hybrid bearings of ISB under the following SC, stainless steel rings are the perfect complement to protect the bearing avoiding corrosion and deterioration caused by the most common external pollutants such as water, dust, mud…
Bearings for ISB steering:
The direction of the bicycle is the mechanism housed between the fork and the frame that in turn houses the bearings that allow the rotation of the fork tube allowing the lateral movement of the front wheel and therefore, the change of direction of the bicycle.
To know what type of bearing we should use, it is necessary to know that there are 2 types of directions depending on the way of joining it to the frame and the type of power used. The so-called “roscada” (threaded)and the “no roscada” (threadless) or ahead where the fork tube is completely smooth, without any thread.
When talking about the different types of directions ahead, reference is made to the different ways of accommodating the bearings in the frame, depending on how it is constructed, to the “steering pipe”.
• Conventional sterns in frames without internal space to accommodate the cups in which case the bearings are mounted in the outer cups.
• Semi-integrated sterns in frames that do allow to accommodate the direction cups and in turn the bearings.
• Integrated sterns in which the bearings are mounted directly, without resorting to the use of cups.
These bearings have a special design different from the conventional one that visibly incorporates light chamfers both inside and outside, whose measurements are determined by the different grades. Therefore, in order to choose the most suitable bearings for our steering, it is necessary to take into account the measurements of the inner diameter, the outer diameter, the height and the contact angles with each of the chamfers.
If we take for example the bearings MH-P08 45º / 45º of ISB indicated for the sterns ahead, the first 45º measurement refers to the internal angle and the second 45º to the external angle. Of all forms, this information is usually recorded on the outer ring of the bearing itself.
The bearings that are mounted in these types of sterns are usually sealed, which avoids recurrent maintenance since the grease remains inside, avoiding the wear of the balls and lengthening its useful life. The sealing protects them in addition to the usual pollutants, temperature, dust, humidity, etc …
Although the bicycle market includes a large number of measures for different types of sterns, the ISB brand offers a wide selection of measures and contact angles that place it among the favorites of the most demanding specialized workshops.