Use these bolt spacings to identify your crank and its smallest chainring.
These cranks have equivalent pcds between 69 and 74mm.
The minimum size of an Oval depends on its ovality - it is greater for ovalities more than 20% and smaller when less than 20%. The minimum number of teeth for 1-bolt cranks may be estimated as follows:
minimum Oval = minimum round 1 - ( 0.004 × ovality )
© Chris Bell