Contec Parts 2015: Bottom Brackets

B o ttom bra c k e ts

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Bottom Brackets

C B B - 1 00      

square tapered, JIS BSA (1,37“) x 24tpi. sealed cartridge bearings boron steel axle different axle widths 280g

0.332.994/3 0.332.995/0 0.332.996/8 0.332.989/3 0.332.997/6 0.332.998/4 0.332.979/4 0.332.999/2

107mm 110,5mm 113mm 115mm 118mm 122,5mm 124,5mm 127,5mm

001695 001695 001695 001695 001695 001695 001695 001695

C B B - 3 00     

ISIS BSA (1,37“) x 24tpi. sealed cartridge bearings different axle widths 225g

0.332.986/9 108mm 0.332.987/7 113mm

003195 003195

0.332.988/5 suitable for MTB/Road

003195

C B B - 5 00       

external bottom bracket for example for Hollowtech II BSA (1,37“) x 24tpi. nylon sleeve, hardened aluminium bearing cups for 68mm and 73mm bottom bracket shell with 3 spacers 105g

TECH-INFO

Bottom Bracket The bottom bracket contains bearings and a spindle which the crank arms are attached to. It is the most heavily used bracket in a bicycle. The force effects even tend to exceed the comparable strain of the crankshaft of a conventional average automobile.

Square taper: You can see by looking at the interface of the bottom bracket to the crank that there are tapered squares. An axial screw connection fixes the crank arms.

There are two types, ISO and JIS which differ by the slope of the wedge and edge form.

Industrial bearings: The spindle has fits where the groove ball bearings are mounted too. This unit is fitted with two bearing cups in the bottom bracket shell. A double sealed industrial bearing ensures a protected bottom bracket.

JIS: The so-called Japanese Industrial Standard normalized a Japanese industry standard and is widely used for Asian machine engineering parts.

ISO: Stands for International Organization for standardization. This is mainly relevant in the European two-wheeler range for older parts.

Multi tooth: This type features many teeth at the ends of the spindle and tapered where it is appropriate. The most common are the eight teeth (Octalink) and ten teeth (International Spline Interface Standard, short ISIS).

External bearings: The bearing cups are placed on the outer side of the bottom bracket shell. The bigger distance between the bearings contributes to stiffness while allowing a lighter construction. It is essential to mount the two bearing cups exactly parallel for an optimum performance and durability.

We recommend that the bottom bracket should be assembled by a skilled person.

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