Neil G
Old School Grand Master
GrahamJohnWallace":25x1dhrp said:I do remember Shimano Biopace BITD, my Muddy fox came with them. Does anyone know why there was a return to round rings if Biopace/oval rings were that good?
The Shimano Biopace rings were next to useless. The rings were oriented the wrong way round so that the gear was lowest during the power stroke and highest at the dead-spot. They did a lot of damage to the reputation of elliptical gear systems.
EggRings are correctly oriented and the ellipse is rotated at 90 degrees when compared to Biopace. The minor axis of the ellipse needs to be lined up to the dead-spot. However the exact position of the dead-spot can change with the type of bicycle. EggRings can also be made to be much more elliptical than Biopace ever were.
Still doesn't get the issue solved though, surely if egg rings are the future and that good then why don't we see them on production bikes, I mean how expensive is an oval chainring to make?