Ovalized head tube :(

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mattyNor
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Joined: Wed Mar 19, 2014 3:18 pm

by mattyNor

The head tube on my steel frame is beginning to ovalize. It's at the point where I can press the cups in by hand about 80% of the way. I have a new frame on the way but it won't get here till the end of the month. Short of buying extra deep cups is there anything I can do to make my current frame last a few more weeks?

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BRM
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Joined: Sun Mar 16, 2014 3:43 pm

by BRM

Probably you use the term ovalized wrongly . . ?
maybe a picture would help to explain and to see what can be done.

by Weenie


eric
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by eric

There's some versions of Loctite made for filling in overly-loose press fits. #640 is one.

It is often used for BB30 bearings that are too loose in the frame. This is a good application for it.
I have used it on cranks with worn splines.

mattr
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Location: The Grim North.

by mattr

Could be ovalised, could be flared.

Solution is the same, loctite bearing fit, as per the last post.
If it's bad, you might need the "permanent" stuff. But probably not..
(It's not really permanent, just a right bugger to remove!)
I fixed a customers bike with this, it was ridden around for another ~5 years without any issues.

Until he got hit by a car.

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BRM
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by BRM

Because he talks about a steel frame I dont think he has Pressfit bearings.
He talks (imo) about pressing in (conventional) cups . . . .

For the few weeks to go before the new frame arrives, I think a temp solution will reach.
maybe support from the outside wil do the tricj for the moment.
Think about a hose-or pipeclamp.
When not enough room for that maybe a single wire clamp will work
http://www.emwardfastenings.com/wire-clamps.html

mattyNor
Posts: 276
Joined: Wed Mar 19, 2014 3:18 pm

by mattyNor

Thanks guys I'll go buy some loctite then. @mattr got it right, the area around the pressfit cups is starting to ovalise/flare (what's the difference?) I'll post a picture when I get home for full disclosure.

eric
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Location: Santa Cruz, California, USA
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by eric

Locktite make a thousand or so different compounds. Make sure you get the right stuff. Thread locker won't work for this. I get it from Mcmaster-Carr.

This will fill in the loose press fit but won't fix whatever is causing the ovalization in the first place unless it's due to a loose fitting headset.

Oswald
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Joined: Thu Jan 08, 2004 10:11 pm

by Oswald

I had a similar problem once on a crossbike and solved it with loctite. Can't remember what type loctite it was, but the fix did last for many years.

by Weenie


mattr
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Location: The Grim North.

by mattr

BRM wrote:Because he talks about a steel frame I dont think he has Pressfit bearings.
He talks (imo) about pressing in (conventional) cups . . . .
And?

Bearing fit is simply to take up space where an interference fit has worn, or is over size.
Flared head tubes are usually down to loose headsets, or over loading the forks. (Or fitting head sets on the p155)

As long as the OP isn't still doing any of the above, Bearing fit *should* be an almost permanent fix.

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