theoretically, the idler _pulley_ doesnt need teeth at all....it's neither a drive nor a driven gear. the only thing it needs is a tight lateral retention system. When forbidden intro'd the "Race Guide" for the previous Druid and Dreadnought, it provided a tighter lateral tolerance that didn't allow the chain to walk off. a consequence of the teeth is that it creates unecessary friction when the chain is crossed to the high or the low side of the cassette.
May 12, 2023, 5:21 p.m. - tdc_worm
theoretically, the idler _pulley_ doesnt need teeth at all....it's neither a drive nor a driven gear. the only thing it needs is a tight lateral retention system. When forbidden intro'd the "Race Guide" for the previous Druid and Dreadnought, it provided a tighter lateral tolerance that didn't allow the chain to walk off. a consequence of the teeth is that it creates unecessary friction when the chain is crossed to the high or the low side of the cassette.