Cleaning the Chain & Old Worn Dura-Ace Cassette - Part 3 -- Another three gears and some special teeth...

On this 15 tooth gear, three of the teeth are different from the other 12 teeth.

These three teeth shape is different and there's a special shape to the width of the teeth also (the bottom tooth in the red box is narrower towards the lower portion of the tooth).

I'm not sure how it works but I think this is the special design that Shimano uses to make shifting gears smoother and more efficient/reliable...

This spacer is needed between some of the gear (not all)...

Between the 15 and 16 tooth gears is one of the places...

Also cleaned the largest gears (23 teeth & 21 teeth).

These two gears have two places on them with the three special teeth, 180 degrees opposite each other.

Placed the gears in order on the holder.

Spacer, then the next gear...

What I've cleaned so far.

A few more to go...