Shimano 105 crank issue.

[g19]

Check this.

http://bike.shimano.com/media/techdocs/content/cycle/EV/bikecomponents/FC/EV-FC-5603-2440A_v1_m56577569830608867.pdf

Can somebody tell me about #5 a ring what this is.
Is this the dust shield cover of the BB?

I can't figure it out.

The #'s 11 & 6 i understand, but the #5 remains a mistery.

I want to make sure because i'm building my bike and would not like to see me assembling things wrong.

The funny thing is that i have bought a complete new set and there was no #5 rings at all.
To make it worse my old 105 10sp that was on a bike from new also didn't had it when i removed it.

Could the pdf from shimano be wrong or perhaps an old group.

Do let me know as you answer is greatly appreciated.

[bike4ever]

The #5 piece is a very thin, black sleeve like piece that is probably pressed against the cups (#7 & #10). Generally this piece is stuck onto the cups. You do want this piece.

[DebW]

There could be a difference in spacers between an installation on an English vs Italian bottom bracket shell (68 vs 70 mm width).

[g19]

Thanks girls,

The original dust shields have a tiny instep on the inside of the shield.
I doubt that this is what shimano see's as the #5.

I do have and had a 68mm BSA BB (my new as well as my old 105 10sp crank).

Is there a technical reason for it to use as it becomes more and more a puzzle to me.

Could this set-up perhaps have been outdated and that the .pdf have not been updated yet?

Does anybody have actually one of these rings on there BB/frame or are we all talking all theorie here.