Shimano 105 Triple Chainring Octalink - assembly question
 

I pulled the cranks on my 105 triple equipped road bike, disassembled the chainrings and cleaned them. Now for the life of me I can't remember which way the middle and inner chainrings face.

Both are stamped with the chainring size. I've assembled it both ways - with the stamp facing outwards I can't get the front deraileur adjusted to shift correctly. With the stamp facing inwards it works MUCH better but when I was in the little chainring and the middle part of the rear cassette the chain tried to suck itself around the chainring (less rear deraileur tension) which makes me wonder if this is correct.

All the LBS's will be closed tomorrow (I think) or I'd go ask one... So I thought I'd ask you guys.

For reference this is the chainring set on a Fuji Roubaix as seen here:

https://www.bicyclebluebook.com/Sear...81&model=40995

Thanks!

Shimano middle and granny chainring are mounted with the tooth count stamp facing inward. Obviously the large chainring is mounted with the engraving facing outward and the chain drop pin opposite the crank arm. Also, the middle ring should be phased with the big ring so the ramps and shaped teeth are mated properly. Check with Shimano's Dealer Manual (https://si.shimano.com/#/ ) for the specifics of this alignment. The granny ring is "flat" and doesn't have to be phased.

Thanks ! I'll have another look and make sure I have the middle gear phased properly.

Isn't the chain drop pin directly in line with the crank arm to prevent chain from being stuck between arm and chainring?

https://cimg9.ibsrv.net/gimg/bikefor...6926d64278.png

Yes. but many cranksets either don't have an anti chain drop pin or are using replacement rings that don't phase their pin location w/ the RH arm.

As to the inner ring not needing to be aligned/in phase with the middle one- One reason for this phase/alignment between rings is to reduce the chance the chain will not release off the ring during shifts, commonly known as "Chain Suck". So rotating the inner out of phase won't make it not work but might see greater chain suck potential. Andy

ronin, I had to smile because of thnking of all the times I have taken stuff apart and when putting it back together, realizing I screwed up the order or position or whatever.

have only recently started to think beforehand to use phone camera more often to avoid screwups/wasting time

re removing rings--if you use an old rag to wipe down chain regularly, its easy to do a quick chainring wipe at the same time. I do it and it just saves time overall, as the little amount of chain oil and stuff that accumulates comes off very quickly and easily.
Sure, there is a bit in nooks, but I guess that depends on how much of a clean freak you are.

Quote:

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Isn't the chain drop pin directly in line with the crank arm to prevent chain from being stuck between arm and chainring?

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Yes. I guess I didn't word my answer properly. By "opposite the crank arm" I meant it should be aligned with the crank arm. It's there to keep the chain from jamming into the space between the chainring and crank arm if the chain spills to the outside.

Got it. We were saying the same thing! There I was thinking I'd done it wrong all my life ;-)

Ya, I agree that I should have taken photos of how it was assembled before disassembling it... and will do so in the future :)