Shimano 5500 crankset arms not in line with each other
 

Hi there!
I need help for a new build.
The frame is a vintage Chesini the group is Shimano 105 - 5500 (9 speed, yellow).
The BB is completely new and genuine for this groupset,the crankset is used but in god's condition.
The problem is that the two crankarms when installed on the BB are not in the same line and I don't get it why.
(Sorry, I cannot attach pictures as I am a new member on this site)

Hope you guys have some ideas,
Thanks in advance

​​​​​​​Dávid

When you get 10 posts post a picture so we can see your problem. Roger

That should be an octolink which will let you install the arms on wrong, being one notch off means unaligned. Was dumb enough to do that once on a customer's bike which made for a funny moment and a bit of ridicule.
It may have a self extracting crank bolt, which would make it easy. just unbolt and reinstall. If you have to use a crank extractor you'll need an octolink specific one.

Octalink bottom brackets and cranks will indeed let you install the crank arms out of line. You have to watch for two possible errors:

1. You installed one arm one notch out of line. Cure: remove and reinstall exactly at 180º apart
2. You didn't get the splines on the crank arm and bottom bracket spindle aligned properly and the splines didn't "nest" fully. Cure: remove and be sure the splines interlock correctly.

Octalink misalignment would mean your arms are some increment of 45 degrees off, since it has 8 splines.

https://cimg5.ibsrv.net/gimg/bikefor...40ed1fa97d.jpg
https://velobase.com/ViewComponent.a...66801&Enum=115

Thanks for the answers.
The thing is that the difference is much smaller than 45° , I removed the arms, checked the BB and it really seems to me that the two sides of the BB are not perfectly aligned (I measured exactly). Is it possible that this particular BB has a factory problem?

P.s. I will make some other posts so I can upload some pictures for you to see

I would be concerned that the splines are "messed up". There was a reason they went to V2 from V1.
Likely an "installer" problem.
What happens if you have the arms at 3 & 9 o'clock and stand on it?

So when installing these cranks the first turn of the bolt is loose and you can align the cranks then. Wiggle them till you find the slot and then tighten. Then the bolt should tighten up as it pulls the crank on.
Your idea of the crank splines not lining up is almost certainly wrong. More like the crank is buggered from installation or not lined up correctly. 45 deg is not correct it is much less between splines.

Bull.
360/8 = WHAT?

@csibi_david If you post in your gallery in your profile, others can see and post in this thread.

Ok so I thought there where more splines and you can sit it against a spline which would leave it less than 45 which the op said it was.
No need to be angry.
Was the rest of the post ok.

It was a waste.
Read posts 5 &7.

Yours where very informative.

Somehow its built wrong. I would suggest getting a pin spanner and removing the outer lockring then the bolt and not removing the arms. See if the splines are actually lined up. I've seen these installed where it was a slightly tight fit so it was assumed things had been lined up and instead it was off by a few degrees and the bb cut slightly into the crank splines. Because it wasn't all the way it was possible to pull the crank and reinstall properly. But you want to look. If this has happened and it cut too deep that arm is garbage. If this isn't it, I've never heard of the arms or bb being milled wrong but anything is possible, I have seen other cranks bent out of straight by BMXers but that seems equally unlikely for road cranks

The only "other" thing I can think of is if the arms are from different models/brands and don't "index" with each other.

That's exactly the situation I described in my post above. When I had a couple of FC-6500 Octalink cranks, I would always remove the autoextracting retaining ring and bolt so I could look at the interface as I assembled the arms onto the spindle. I was remarkably easy to butt the splines up against each other rather than nesting them correctly is you didn't watch.

blamester & Russ Roth are on the right track.

In my experience with Ultegra 6503 triple Octalink cranks, the One-Key Release makes removal with an 8mm Allen wrench easy.

It is with reinstallation where the one key release can make you think that the splines are fully lined up when they are not. So csibi_david - I believe with your 5500 crank the first thing you should do is to back off the 8mm Allen bolt and examine the spines on the back of the crankarms and also the BB axle splines for gouging. Hopefully they are not damaged.

For proper reassembly I have found that an 8mm Allen socket mounted on a sliding T-bar offers the necessary tactile feedback to apply even, 2-sided pressure to the bolt as it is snugged down. A short Allen wrench does not. I apply grease to the threads in the hollow axle in order for the One Key bolt to turn smoothly. Grease on the splines I believe is optional. As you start the threading the first turn or two with the T-bar onto the spline, you can wiggle the crankarm slightly forward and back to gauge if the splines are mating or “riding high”. If it is the latter, it will clunk down then you will feel that the splines are now squarely mating up on a sort of 8 point taper. Your T-bar with 8mm Allen socket can now be used to safely advance the crankarm with even pressure until it bottoms out. If you do it this way you will feel the greased threads and know that you have done it correctly, no torque wrench required.

The opposite crankarm installation is identical. You can visually tell if you are one spline off in which case Bill Kapaun is correct and that would be an obvious macro mismatch of 45 degrees from horizontal (drive side to non-drive side).

If you do the technique I outlined above where you wiggle the crankarm side to side when you first start to attach the 8mm One-Key release bolt, it will drop onto the splines correctly and you can pretty much see from the get go that any wonky-ness (if there was any to begin with) has now been dealt with and the arms are completely tight on their splines and in line with each other.

I hope this helps.