THM Clavicula Crank install help needed

Discuss light weight issues concerning road bikes & parts.
marchitect
Posts: 52
Joined: Mon Sep 14, 2009 10:10 pm

by marchitect

I have about 6500 miles on my THM Clavicula (Road bike crank). I've had zero problems until just recently.
The drive side bearings have come loose. To tighten them I need to remove the crank.
The Clavicula was so incredibly hard for me to install originally I am not looking forward to doing it all over again to re-tighten the bearings.

People say to "TAP" the crank into place. Are they serious?!?!? Tapping with a rubber mallet didn't work for me. The proper word is pound with the mighty force of God.
Also, the sexy but uneven surface of the crank makes it very difficult to pound in with a mallet.

Should I just put soft towels on the crank and pound it to death with a rubber mallet to get in into the BB assembly?
That just seems ridiculous, but I'm not a pro bike mechanic. Maybe if I had a pro do it, they would use the same force and not worry about it.

If people can provide assistance on how to best get the Clavicula crank back into place that would be greatly appreciated.

Thanks Thanks Thanks !!

Simon BP
Posts: 1275
Joined: Tue Jun 17, 2008 7:46 pm
Location: Denmark

by Simon BP

grease is a good thing.Put it on the alloy bits on the axle, and on the inside of the bearings. That helps a little. But for God sake, don't use a hammer of any kind on those cranks!! Use your palm to hit it into place. And keep the crank aligned with the bearings. If you start to get off alignment, it just gets harder.

by Weenie


timzcat
Posts: 315
Joined: Thu Sep 30, 2010 5:50 am

by timzcat

Put it in the freezer for an hour.

Simon BP
Posts: 1275
Joined: Tue Jun 17, 2008 7:46 pm
Location: Denmark

by Simon BP

U are kiddin, right?

sedluk
Posts: 409
Joined: Mon Sep 07, 2009 3:10 am

by sedluk

He is serious, metal gets smaller when it is cold & bigger when warm.

xnavalav8r
Posts: 2643
Joined: Mon Jan 21, 2008 12:09 pm

by xnavalav8r

The cold idea isn't a bad one. I installed my Claviculas in my garage during the winter and had no issues. I had a hell of a time getting them off in the same garage on a hot summer day. Frustrated by the heat, I brought my bike inside to work on it. After a short while in the air conditioned house, the cranks came off easily... no freezing required.

Note: I did use a soft rubber mallet to gently tap the axle through for both installation and removal.

marchitect
Posts: 52
Joined: Mon Sep 14, 2009 10:10 pm

by marchitect

Thanks for everyone's suggestions.
I don't know what it is, but my crank seems to be significantly harder to remove and install than others.
The idea of tapping would be great but it's more like major pounding.
Using the palm of my hand as one person suggested would require "Iron Man" strength.
I'm going to give it another go and we'll see what happens.

marchitect
Posts: 52
Joined: Mon Sep 14, 2009 10:10 pm

by marchitect

I don't understand the freezer or cooling idea.
The metal will, as you say, get smaller when cold. The only metal is the bearing cups.
I don't think the carbon fiber crank will react like metal will when cold.
If the bearing cups get smaller, they will essentially squeeze down on the crank spindle making it even harder to remove.
I would understand heating but cooling is a stretch for me to understand.

skywalker268
Posts: 65
Joined: Tue Jul 07, 2009 11:28 pm

by skywalker268

When you cool the crank, you cool the spindle as well. Cooler spindle=smaller diameter=easier to install into the bearing cups.

timzcat
Posts: 315
Joined: Thu Sep 30, 2010 5:50 am

by timzcat

There are quite a few posts about this on here. First time I installed my Rotor BB30 crank it required a rubber mallet to install. When I took it back out I got the idea to put it in the freezer to reduce it's size. It slides right in with no mallet whatsoever. Used to do this to install steel valve guides in aluminum cylinder heads, if you don't freeze them you absolutely cannot install them at room temperature.

As far as Clavicula, is the entire spindle carbon?
Also, many things shrink slightly when cold, not just metals.

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andy2
in the industry
Posts: 713
Joined: Sun Dec 16, 2007 9:33 pm
Location: Luxembourg / Sweden

by andy2

The 'old' Clavicula has a carbon shaft with metal bearing races that will shrink when chilled. So by leaving the cups on the bike, and out of the freezer, the frozen ds crank arm and shaft assy will slip right in. Applying a thin film of WebGrease will also help. Also remember to follow the instructions when mounting the nds arm.

/a
rolobikes

xnavalav8r
Posts: 2643
Joined: Mon Jan 21, 2008 12:09 pm

by xnavalav8r

YES! Follow those instructions and use a torque wrench. The threaded insert on the non-drive side is bonded into the spindle. Too much torque will either strip the threads or pop it completely free of the spindle. I personally experienced the latter. THM was very kind to repair the crank for me, but that experience was painful.

marchitect
Posts: 52
Joined: Mon Sep 14, 2009 10:10 pm

by marchitect

That's good news.
I wasn't aware that the carbon fiber spindle would shrink when cold.
I will take the crank off the bike, put the Clavicula in the freezer and give it a shot.
If I can push it into place using just my hands that would be great.
I'll keep you posted on the results. I plan to do this during the weekend.

Cheers.

marchitect
Posts: 52
Joined: Mon Sep 14, 2009 10:10 pm

by marchitect

Thanks for the freezing suggestion.
It worked great.
I warmed up the bearings with a hair dryer (60 seconds) and froze the crank for 1 hour.
Put a thin layer of grease on the contact points and I was able to press it in with the palm of my hand.
It's all installed now and functions perfectly.

by Weenie


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andy2
in the industry
Posts: 713
Joined: Sun Dec 16, 2007 9:33 pm
Location: Luxembourg / Sweden

by andy2

:no1: :thumbup:
rolobikes

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