O.L.D. (Over-Locknut Dimension)

O.L.D. stands for Over-Locknut Dimension.

This is the width of the hub measured from outside of locknut to outside of locknut. It is not to be confused with the axle length, as the axle extends into or beyond the frame dropouts.

The O.L.D. needs to match the available space in the frame between the fork or frame tips.

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Rear Hub Widths & Dropout Spacing

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Rear hubs vary in width (but most new ones are 130mm for road or 135mm for mountain). The hub width (over-locknut dimension) needs to match the space between the rear wheel dropouts in the frame in order for things to line up as they should.

120mm: 5 speed and "Ultra-6". An old hub size not used on new bikes.

126mm: 6 speed and some 7 speed.

130mm: 8 & 9 speed road.

135mm: Mountain 8 & 9 speed and some 7 speed.