Does anyone know what the purpose of the ring behind the spacer is? I have a new 6703 crank and may have lost the ring. It wasn't in the bag the spacer and cap came in. So if I install the crank without the ring what impact will it have? I think the ring is a new feature of Shimano cranks. A 7803 crank I have doesn't have a ring under the spacer.
The Shimano part number for the ring is Y-1F3 1600, I assume any Shimano dealer can order one for me. I haven't found one online yet.