masi61

I bought a used Dura Ace 7800 crank on eBay that was the drive side only (right side) with the intention of matching it up to an orphaned 172.5 non drive side crank arm. The price was low and I thought I could use it on one of the inexpensive bikes I'm fixing up.

Just yesterday I had the 7800 crank off my Veritas titanium bike and looked and saw where there is a thin nylon flanged bushing/spacer on the inside of the drive side crank where it contacts the outboard bearing.

Then I looked for the spacer thing on my used 7800 eBay crank and realized that it is missing the spacer. So I set out today to get a better look at some tech documents that can shed some light on whether this part is optional, or necessary in this spot. My initial google search has come up empty. Could anyone share a link that would show an exploded diagram for this crank with all the small parts and part numbers listed? I seem to recall seeing some German Shimano website where they have archives of the Shimano "tech docs" on older, out of production Shimano parts.

Also, does anyone have any suggestions on how to obtain this little spacer/bushing if it turns out to be an essential part?

Thanks for any help. And in the mean time, I'll keep looking.