Check this.

http://bike.shimano.com/media/techdo...9830608867.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.