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118mm Bolt Circle Diameter, 5-Bolt chainrings

118mm Bolt Circle Diameter (BCD), 5-Bolt chainrings on this page:
SR: 40-tooth | 52-tooth

Back to master list of available chainrings

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Bolt Circle Diameter is the diameter of the circle formed by the centers of the chainring fixing bolts. With 4-bolt cranksets, this is easy to measure. 5-bolt cranks are more difficult.

If you are unsure about what size chainring you need, Wolf Tooth Components has an excellent guide to measuring your rings.

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SR Apex-5 40-tooth 118 BCD chainring. Used, $30.00/each

Works on several 1980s Campagnolo cranksets

Here's the other side of the ring

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SR Apex-5 52-tooth 118 BCD chainring. Used, $45.00/each

This ring is drilled and tapped for an SR alloy chainguard. That's what those five small threaded holes on the ring's perimeter are for.

Front side

The back side

Close-up showing that it is an Apex-5 ring as well as the amount of wear on the teeth.