The chainrings on my new bike have broken or missing teeth. What is going on?
‘Missing’ teeth is another Shimano innovation, near every other company now emulates. The odd missing tooth facilitates faster downshifting because it makes it easier for the chain to move onto a smaller chainring. Similarly, ramps, pins and twisted teeth facilitate upshifting into a bigger ring. Thanks to Shimano’s engineering ingenuity, Shane McGowan-like twisted or missing teeth do not prejudice the chainring’s primary responsibility which is to turn the chain.
