How do I shim a loo...
 

[Closed] How do I shim a loose crown race

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I've got an old BMX fork (1") and a new crown race (26.4) which is loose. After cleaning up the fork and original crown race, this also has play in it. So I need to some how make up the difference. But how do I do this? Any advice welcome.


 
Posted : 14/04/2019 9:06 pm
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Using a punch around bottom of steerer to create small raised nicks can work.


 
Posted : 14/04/2019 9:26 pm
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I might try a bit of stud and bearing fit depending on how loose you are talking about


 
Posted : 14/04/2019 9:38 pm
 Yak
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Cut it.


 
Posted : 14/04/2019 10:00 pm
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Glue or epoxy resin?
Or cut and squish it in a bit.


 
Posted : 14/04/2019 11:51 pm
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Cut it.

Unless it's actually a race for balls & stuff, but in that case it will also put up a fair fight.


 
Posted : 15/04/2019 6:49 am
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Loctite retaining compound, there's a few, maybe 660.


 
Posted : 15/04/2019 8:53 am
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It's old school and the bearings and races are separate so I don't think cutting it will work. What would happen if I melted som electrical solder between fork an race?


 
Posted : 15/04/2019 5:44 pm
 JoeG
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See if you can find a bike shop that has one of these:

https://www.steintool.com/portfolio-items/knurling-tool/


 
Posted : 15/04/2019 6:18 pm
 ctk
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Coke can shim worth trying before using solder.


 
Posted : 15/04/2019 10:51 pm
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I've done it before (the proper way).

Build up the diameter with brass (brazing rod and gas torch). Then find someone with a decent size lathe. Hold steerer in the chuck and recut the seat. Silver solder would also work but runnier so harder to build up (and more expensive). I wouldn't bother with soft solder.

Loctite bearing retainer isn't going to fix it a 1mm diameter difference.


 
Posted : 15/04/2019 11:20 pm
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Just a thought, have you built it up and checked that there's a problem when it's pre-loaded? That play in the fork and original crown race might have always been there and nobody ever noticed until it was disassembled? Punch is a good shout otherwise but if used in anger the dimples might get hammered out in time.


 
Posted : 16/04/2019 3:58 pm
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Dutch courage - a bit of a heineken tin

P.S. Thanks to all that gave advice.


 
Posted : 20/04/2019 5:58 pm
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BITD ( which stands for " back in the day !!!) , We sat them in car body filler.


 
Posted : 22/04/2019 8:45 am
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The Locktite 660 will fill a surprising gap, spec is .5mm but we’ve seen more very successfully done but it’s expensive. I’d definitely try the coke can shim, you be amazed how well that has adequately bodged race cars, race bikes and even aeroplanes around the world.


 
Posted : 22/04/2019 9:02 am