Race Face Narrow Wide Single Chainring - 104mm - Green. BBB CompactGear Chainring 38T Shimano Fit - BCR-31 9/10 Speed 110mm. Race Face Narrow Wide Single Chainring - 104mm - Orange. We arrived at an optimal 10% ovality and 112.5° clocking, which can be achieved in both regular and flipped Super Boost positions by following the orientation callout on the rings.