2 crown races on my...
 

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[Closed] 2 crown races on my forks

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 DM52
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I have 2 crown races stacked on my forks to add an extra bit of clearance from the dials on the top of the fork legs and the cable stops on the down tube, 1 crown race means the stops hit the fork.

Everything seems to be all done up correctly and there is no play in the headset, test ride is going to be next weekend at Swinley.  Recipe for disaster or a neat solution to the problem?


 
Posted : 23/05/2018 10:59 pm
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Do they even come with forks?


 
Posted : 23/05/2018 11:10 pm
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Seems like a stupid thing to do. Most forks are a larger diameter locally where the crown race sits. Also, depending on the shape of the crown race the top of one may not sit nicely against the bottom of the one on top.

I wouldn’t do it.


 
Posted : 23/05/2018 11:15 pm
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What Bigwatts said.

Dependinv on the headset some manufacturers like king and Cane Creek make a +5mm race for this purpose.

I wouldn't be surprised if you get some lateral play if the upper of the two lower races is sat on the steerer above the purposely larger diameter area.


 
Posted : 23/05/2018 11:23 pm
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wot they ^ said

or, depending on the frame and what's already in there, an external-bearing lower headset cup might be better


 
Posted : 23/05/2018 11:34 pm
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As above, it's not a good idea!

Even if there seems to be a large enough large flat area at the bottom of the steerer to take the two crown races before the taper starts there usually isn't.  That flat part usually has a slight taper to it too to help the crown race grip correctly when pushed on.  If you take one of the split crown races you can get and slowly push it on square you can see the gap continues to open up ever so slightly just before it contacts the crown itself.  The correct solution is one of the +5mm options mentioned above.  This problem you're having is why some newer bikes are coming with headsets that restrict the turning movement of the forks.


 
Posted : 24/05/2018 6:30 am
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I just had to add a 2mm 30mm spindle spacer to my kids 1.125 steerer fork as when tightened the Durins crown binds on the lower cup.

Not my ideal scenario and he might not ride it as I'm not sure we have dental coverage to replace his teeth if it all goes horribly wrong.

He also might ride it as it<span style="font-size: 0.8rem;"> works perfectly in the stand  ;)</span>


 
Posted : 24/05/2018 6:38 am
 DM52
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Interesting thoughts, I didn't even know +5mm races even existed and will look into that, a cursory google has only revealed taller headset cups so far for the cane creek headset (think mine is an s8).

The frame is old - commencal absolute VIP 2006, the forks are older - Fox 36 2005 but it is all I currently have other than a DH bike.

With the current 'setup' both races seem to have hit the taper, the top race was a lot harder to seat than the bottom so I assumed there was enough taper for both.  I am kinda thinking or hoping with everything done up correctly it is not going to fall apart like a clown car and at worst the headset will work loose as the stacked races are potentially squished together a bit more.

I acknowledge it is not ideal and a bit of a bodge.


 
Posted : 24/05/2018 11:24 am
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I think my worry would be that the second race doesn't sit quite square on the steerer and you'll end up damaging the headset or steerer. Unless the second race has a flat surface to seat on, it might tend to move around a bit.


 
Posted : 24/05/2018 11:35 am
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that's my thought - the second race will slip down the taper of the first on one side and end up at an odd angle relative to the crown and bottom headset bearing.


 
Posted : 24/05/2018 11:37 am
 DezB
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there is no play in the headset

I reckon if this is the case, then it should be ok (should). As soon as anything isn't seated correctly you'll feel the wobble in the forks and that would be the time to give it up as a bad job.

Trouble is, you'll (well I would) be riding with it on your mind all the time. "Is this gonna hold up?" Especially now you've started a thread about it!


 
Posted : 24/05/2018 11:40 am
 DezB
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Just a thought - what if the bottom one was upside down? Then they'd sit together nicely... (If they aren't already)


 
Posted : 24/05/2018 11:42 am
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Then you'd have the 'point' of the lower race trying to dig it's way into the steerer/crown joint every time there was any force applied?


 
Posted : 24/05/2018 11:44 am
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I'd feel a lot more comfortable with some large flat washers or something under there. I'm sure an engineering shop would be able to sort something out.


 
Posted : 24/05/2018 11:49 am
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Why is the fork dials hitting the crown a problem? How many turns are you doing where you need over 70 degrees of bar turn? I'd fit a bit of rubber to the underside of the crown if I was concerned about them hitting during the one crash a decade where they actually touch and ride it with a much safer single crown race.


 
Posted : 24/05/2018 12:09 pm
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I have had a similar issue and a taller crown race was the correct fix: https://www.charliethebikemonger.com/cane-creek-3mm-40mm-lower-race-custom-for-salsa-7676-p.asp


 
Posted : 24/05/2018 12:17 pm
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Product Information

Cane Creek +3mm 40mm Lower Race custom for Salsa

Headset crown race that stacks up by around 3mm.

This is used to get a Bluto sus fork to clear the downtube on a Beargrease.

Apparently very rare.

Stock Status: Sold Out


 
Posted : 24/05/2018 12:26 pm
 DM52
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I don't think a 1 1/8th steerer is compatible with a 40mm race anyway.

To answer Munrobikers question, I was trying to avoid damaging the forks rebound and travel dials in the event of an accident, I had not thought too hard about the potential ramifications of the crown race kludge.


 
Posted : 24/05/2018 1:34 pm
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I agree with DezB, if the 2nd, higher crown race is a good press-fit on the crown, should be OK.

Certainly not going to be any catastrophic failure.


 
Posted : 24/05/2018 2:10 pm
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The 2nd crown race will not seat properly on the taper of the first unless you machine them to match. It will "work" but it is point loading and will deform.

If you want a better bodge and the the crown race is tight further up the steerer a flat spacer would be a better solution.


 
Posted : 24/05/2018 2:16 pm
 DM52
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I am thinking maybe long term this is what I am after:   https://www.ebay.co.uk/itm/41-8-52mm-Bike-Headset-Base-Spacer-Crown-Race-Bike-Headset-Washer-Bicycle-Parts-/152584218906


 
Posted : 24/05/2018 2:54 pm

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