Octalink V1 Fitting

[simpatexys]

Hello fellow Retrobikers, trying to tap in all the knowledge this forum haves with the following conundrum.
I've got a NOS DA7700 Crank (FC-7701) I know that it takes a Octalink V1.
Recently I purchased a BB5500 and went about trying to fit them, but it seems that the BB splines are too thick to fully enter the crank!!! Now, I've checked Sheldon Browns page and the spline length on this BB match the V1 version and 105 always had Octalink V1 fitting I've also contacted the seller of the BB and they swear they've sold hundreds of them and no one ever complaint. The engagement only happens for about a millimeter between the BB splines and the crank so I'm kind of losing the plot here.
Is it maybe the cranks spline gaps that are needing a bit of filling, maybe the cast came out too thick and left some unwanted extra material in there?
Any thoughts?

 

[mdvineng]

They are supposed to cut their way into the crank arm when fitted for the first time, so that they are a real snug fit.

 

[simpatexys]

Re:

Really! I had a feeling about that but was afraid of forever damaging a NOS crank.
You've been through this I guess... Any pointers on installation?

 

[ishaw]

Re:

I had a similar issue using m950 cranks and an m952bb. Both were v1 splines but I could not get them to work together, the BB simply wouldn't fit and I didn't want to force it.

I ended up finding an m950 BB which when compared to the m952 looked exactly the same, but it fitted???

My advice on fitting is to remove the self extractor bolt covers so you can see it all line up properly, then tighten/torque the bolts up and finally fit the covers once you are happy.

 

[simpatexys]

Re:

I've even had a BB-7700 NOS and still there was no engagement or meshing. I really think the casting might be defective on this

 

[mdvineng]

Re: Re:

Really! I had a feeling about that but was afraid of forever damaging a NOS crank.
You've been through this I guess... Any pointers on installation?

Line it up and then torque to the correct setting and all will be fine.

If it slides on it will always be loose, crap design, which is why it was short lived.

Never had any issues with square taper in 35yrs and currently trying hollowtech2 on one bike and one bike still on octalink v1

 

[syncrosfan]

This is a very interesting thread as I've had the same problem with a set of NOS Sibex Titanium cranks which I acquired a little while ago. The BB axle interface is Octalink V1 by all accounts, however the spline engagement is about 1mm before they bottom out without applying extra force. I have taken off and installed my fair share of XTR M950 and 952 cranks over the years and all of them engaged way more than 1mm when just being set on the axle with hand-force alone (obviously those cranks weren't NOS). I was kind of freaked out by the engagement issues of those cranks to the splines (shoddy machining? not a V1 spline?...) this thread sheds a light on the possible issue of NOS crank to Octalink interface. I'll follow this eagerly, to see if just cranking them up to the factory spec (which was pretty high as far as I remember) will take care of the interface issue.

 

[simpatexys]

Re:

Syncrosfan, I'll try and keep you posted.
You cannot believe how happy I'm to hear that this is not ONLY happening to me! Thinking about giving the crank splines spaces an extremely careful sanding, it seems they are off by about 0.3mm. Now I just need to find out which ones have the extra cast material so I don't end up F%$£ing up the NOS crank :?

 

[syncrosfan]

Will look forward to see some updates.

 

[mdvineng]

Re:

This is copied from another forum that posted a similar question and the answer is

Other than the obvious visual lining up of the splines before you push them together, I don't do anything special when installing Octalink cranks. I've only used Octalink on mountain bikes, so I can't comment on the compatibility of the cranks and bb you're talking about, but I've always found it to be very simple to get the cranks on the bottom bracket spindle with the ones I've used. Grease the splines liberally, eyeball the alignment, and push the cranks onto the spindle with your hands to get them started. They won't go on too far with just your hands pushing, but you should be able to feel that the splines are aligned properly, as there's a distinct feeling as you push them on that the splines are engaged and are sliding together. Good luck-

So once at that stage fit the bolts and torque up