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Discussion Starter · #1 ·
I am building up a Cervelo Soloist and just finished installing the BB and Crankset. This is a first for me.

The BB is a old Shimano DA 7700 octalink which is in excellent condition - I just finished re-lubing it and it works great (smooth).

After finishing the install, I noticed the outer chainring (50 tooth) is 5 or 6 millimeters beyond the outer arm of the front der cage. I can't figure out why!

The BB bearing cup on the drive side is tightened with the face of the cup's head flush against the outer edge of the BB.

The non-drive side bearing cup is also tight - some threads are exposed beyond the BB but that is normal as a nut threads onto those threads.

The crank arms are tightened with the retaining bolts and the heads of the bolts are flush with the outer face of the crank arm which is normal I believe

Any ideas what is causing the issue? Am I over-looking something.

Thanks in advance.
 

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A pic might help but I'm assuming the the big ring lies outside of the FD cage when it is shifted to the big ring, otherwise what you describe sounds normal to me. Does it shift OK?

What crank are you using? Is it the right bottom bracket for that crank? I'm a Campy guy since about 2005 but I don't recall a compact crank with 7700 Octalink. Your spindle may not be long enough for your crank. Other thing to check is the stops on your derailleur, the tiny screws that limit how far in and out your derailleur can swing.
 

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Discussion Starter · #3 ·
I think I found out what the problem is.

The bearing spindle on a Octalink BB has 8 thin ribs on the end. The crank arm has 8 thin slots which need to align with the ribs.

I looked and the ribs and slots are not aligned, therefore the crank arms do not fully engage with the spindle.

Tomorrow is another day - I will remove the crank arms and line them up correctly! I will sleep better tonight:)

Thanks anyway.
 

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I think I found out what the problem is.

The bearing spindle on a Octalink BB has 8 thin ribs on the end. The crank arm has 8 thin slots which need to align with the ribs.

I looked and the ribs and slots are not aligned, therefore the crank arms do not fully engage with the spindle.

Tomorrow is another day - I will remove the crank arms and line them up correctly! I will sleep better tonight:)

Thanks anyway.
Unless you've done dozens and dozens of times NEVER install an Octalink crank w/ the bolt and cap on. Remove them so you can be sure you're lining up the splines correctly. I hope you didn't tighten your crank bolts to the proper torque w/ the splines not engaged correctly...if you did you ruined your crank.
 

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Also make sure your crank isn't for an ISIS bottom bracket as it looks a little like Octalink.
 

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Also make sure your crank isn't for an ISIS bottom bracket as it looks a little like Octalink.
I was just going to say the same.

OP has yet to tell us what the crank is.

Was Octalink only Shimano or did others make compatible cranks?

There's also this from wiki. So another possibility is that OP is using a v2 crank on a v1 spindle. Coincidentally this would result in the crank being 4mm further out.

The Octalink system uses a spindle with eight splines. The splines provide a contact area between crank and spindle for an interface. Octalink exists in the marketplace in two variants, Octalink v1 and Octalink v2. The difference between the two can be seen by the depth of mounting grooves on the bottom bracket spindle. V1 spline grooves are 5 mm long, while V2 are 9mm long. 105, Ultegra 6500 and Dura Ace 7700 cranksets mate to version one bottom brackets, while later mountain bike designs use the deeper-grooved version two. The system is proprietary and protected by Shimano patents and license fees.
 

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Discussion Starter · #7 ·
Lined up the splines and slots and tightened bolts to the recommended torque. Front der now shifts correctly. Great!
 
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