Bionic chainring to give you bionic legs?
Aside from being ‘different’ and failing the Internet Engineering test, a big reason that oval chainrings haven’t done especially well is the fact that they have traditionally made front shifting… crap. With the increasing move toward one-by drivetrains, shifting becomes a non-issue- and non-round ‘rings seem to be making a stealth comeback.
The oval rings vary from an effective size of +2 teeth (relative to nominal) where the legs are strongest while dropping back to -2 teeth where they’re weakest. Those forever scarred by The Great Biopace Experiment need not worry: at 90 degrees out of phase with Shimano’s attempt to smooth out riders’ pedal strokes, these ovals have the opposite effect.
The latest -B|Labs’ OVAL- appears to be one of the better-considered of this new batch. Designed for 1×9, 1×10, and 1×11 drivetrains, the chainrings make use of narrow/wide teeth to keep the chain in place without the need for a guide. B|Labs has offset the chainline to allow for quieter and more efficient running on double cranksets (even better running on the centre position of triples). 104mm BCD versions also have threads allowing bolts to thread directly into place. Of course, aesthetics are key- and the skip-tooth looks will strike a chord with anyone who has spent time around old-timey block chain bicycles.
The B|Labs OVAL chainrings will be available in SRAM direct-mount (£55) and 104mm (£45) configurations. With no bolts in the way, the former range from 28t to 36t sizes, the latter run from 32t to 36t. Direct-mount and triple fitments will yield a 49mm chainline; 2x10s come out to 51mm. Shipments are scheduled to begin 5 November.
Photos © WOMB magazine