Can you cut a crown...
 

[Closed] Can you cut a crown race?

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Rather than use a selection of Stanley knife blades as wedges or my crown race puller, is it practical to cut the race with a Dremel device, and use the crown race?

Benefits seem to be it would be easier to fit and remove but it may have a site for the ingress of dirt/water in the little gap.


 
Posted : 18/02/2016 3:24 pm
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Many come already cut


 
Posted : 18/02/2016 3:25 pm
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breninbeener - Member
Rather than use a selection of Stanley knife blades as wedges or my crown race puller, is it practical to cut the race with a Dremel device, and use the crown race?...

I do this to every solid crown race that comes my way, only I don't cut it right through. I leave just enough metal so there's no gap (helps keep the crud out). It's enough to allow the crown race to go on and come off without needing a lot of force.


 
Posted : 18/02/2016 3:31 pm
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It depends if you have a sealed bearing or loose bearings that run directly on the crown race common on older or cheap headsets. With sealed bearings, some like Hope come with a cut already. I have heard of people cutting uncut rings but I have never tried it myself. Loose bearings running directly on the crown race you have no chance for obvious reasons.


 
Posted : 18/02/2016 3:31 pm
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We did this a month or so ago. Some people say fine, other people say you're violating special rules of bike building.


 
Posted : 18/02/2016 3:31 pm
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Loose bearings running directly on the crown race you have no chance for obvious reasons.
To be clear - if it's a sealed bearing then it's not really a crown race anyway ๐Ÿ˜†


 
Posted : 18/02/2016 3:33 pm
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Done it several times for sealed bearing headsets with no problems.


 
Posted : 18/02/2016 3:37 pm
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yes, but only cut it in one place ๐Ÿ˜€


 
Posted : 18/02/2016 3:44 pm
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I did on the last couple of bikes I built. Doesn't make a difference from what I've noticed. Tend to fit it facing forward (more crud at the back) and put a blob of grease in before I drop the headtube down.

Was important on my SS as I used to change between rigid and suspension forks for winter/summer.


 
Posted : 18/02/2016 4:14 pm
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Thanks guys, i appreciate the input! I will remember to only cut it once...:-)


 
Posted : 18/02/2016 4:30 pm
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I always cut mine if needed (none of my bikes have loose bearings though).

The trick comes when there's a rubber seal- cutting the metal not the rubber is an art.


 
Posted : 18/02/2016 4:30 pm
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The rubber usually comes off...


 
Posted : 18/02/2016 4:34 pm
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Well ****. Really?


 
Posted : 18/02/2016 5:43 pm
 nikk
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The rubber is there for a reason.

Why cut it and make an entry for crud / water, and possibly put more pressure on the steerer?

Fitting is easy with a pipe the right size and a crown race setting tool. Removing should be a rare event (changing headset type).


 
Posted : 18/02/2016 5:46 pm
 cp
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As above, the rubber is usually just a tight fit over a lip, it comes off. Cut the crown race and put the rubber seal back on.


 
Posted : 18/02/2016 5:49 pm
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I just give the race a tickle with a blow torch then push it on with a bit of plastic pipe works perfectly.

Having cut one race and not getting the headset to stop clicking i decided not to bother again


 
Posted : 18/02/2016 7:05 pm
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I've cut all mine, no issues.

Put the gap at the side.


 
Posted : 18/02/2016 7:10 pm
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Bit of silicon in the cut? Let it cure..


 
Posted : 18/02/2016 8:18 pm
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I've cut one with the intention of running the cut at the front to avoid wheel spray. But after cutting it I realised I'd cut the back. It's the old measure twice cut once rule.


 
Posted : 18/02/2016 8:42 pm
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put more pressure on the steerer?

Really?


 
Posted : 18/02/2016 8:46 pm
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Works Components.


 
Posted : 18/02/2016 9:00 pm
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I've cut one with the intention of running the cut at the front to avoid wheel spray. But after cutting it I realised I'd cut the back. It's the old measure twice cut once rule.

๐Ÿ˜ฏ ๐Ÿ˜†


 
Posted : 18/02/2016 10:04 pm
 nikk
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put more pressure on the steerer?

Really?

For sure. It is a wedge, so will tighten up and put force inwards onto the steerer (pinching the steerer) if it is a cut circle. Whole, the force is held around the race, so isn't transmitted to the steerer. From an engineering POV, it is much better whole.

Cutting races seems a hack for little reason. I have never found whole ones hard to put on (using the right tool).


 
Posted : 19/02/2016 9:27 am
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How can it be both an entry point for crud/water [i]and[/i] be pinching the steerer? I can understand one argument or the other but not both simultaneously.

Many manufacturers supply split "races".


 
Posted : 19/02/2016 9:33 am
 nikk
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The gap means it is an entry point for water.

The gap means the vertical wedging force applied to it from the bearing is converted to a circular clamping force on the steerer.

It may not matter in most cases, but to me it is just a less optimal design.


 
Posted : 19/02/2016 9:36 am
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LOL


 
Posted : 19/02/2016 10:00 am
 cp
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. I have never found whole ones hard to put on (using the right tool).

It's getting them off which is a pita on a crown without slots to get a screwdriver under. Engineering perfection it may not be, but the convenience factor far out weighs it.


 
Posted : 19/02/2016 10:11 am
 cp
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Posted : 19/02/2016 10:26 am
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It's getting them off which is a pita on a crown without slots to get a screwdriver under

There are tools for that, you can use something like the one below or the Park Tool (CRP-2) abomination. I do cut the crown races myself when needed.

[img] [/img]


 
Posted : 19/02/2016 10:32 am
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I might add these days I buy only Hope headsets because of the split crown race (ok, it isn't a crown race).

The design of steering bearings on bikes is an evolutionary kludge which is why we have all this faff and need for special tools.

It would be simple enough to design a foolproof sealed system that would last the life of the bike, but we would need to redesign forks while we're at it.


 
Posted : 19/02/2016 1:19 pm