Lessons from my recent stupidity

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Jeremy S's picture
Jeremy S
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Joined: 6 May 2013

A couple of weeks ago I noticed some new creaking sounds from the boom area of my Silvio, which had been silent since the last time I greased and tightened everything. The sounds appeared to be coming from the slider clamp (which clamps the boom above the fork). After some disassembly I discovered that the clamp is damaged. The clamp bolt is keyed at one end to fit into a notch in the clamp, and the notch has expanded. The surrounding area is also a bit scraped up.

I can’t be sure this is causing my creaking problem, but if you want to avoid similar damage here is my advice:

  • Obviously don’t try to over tighten or gorilla-arm the bolt.
  • Do not try to pick up the bike by the boom, or clamp the boom to a repair stand, while the front wheel is off. Without the front wheel skewer to hold the front triangle together, the boom will act as a big lever putting torque on the clamp/bolt assembly. I think this is what messed me up in the first place.

Here are the photos where you can see part of the clamp notch has been turned into a wedge. I imagine the bolt is made of harder metal than the clamp.


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AndrewBaloga
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That's good to know, but it

That's good to know, but it sucks to find these things out. It's a shame that's a specialty piece; I can't imagine you'd find a replacement at any bike shop or from problemsolvers.com. I do wish that clamp could be retrofitted onto the first generation Silvio. The slider clamp on those is a bit of a paperweight! Of course, it is darn-near indestructible.

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Doug Burton's picture
Doug Burton
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Don't be hard on yourself...

The clamp is robust enough to handle the maintenance stand thing.

If you put a bit of waterproof grease on the bolt head landing areas on the clamp, it should return to silent running. The keying function isn't all that critical if the bolts are properly tightened. If you really want a clean key hole, you can use a fine Dremel bit and cut a new one on the other side and reverse the bolt.

The SV1.0 used to break from those bolts too, though they were a different configuration.

I suspect John might be able to come up with a replacement, particularly if he's ordering components for another production run. You might PM him about it...

Best,

Doug

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mzweili
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BOOM CLAMP

Jeremy,
I don't think the notch on the boom clamp hole is of great importance, it's probably there to simplify assembly. The boom clamp is made of  aluminum and the bolt is probably in stainless steel, so if the bolt/notch is not properly aligned it will result in what you show in your picture. But that will not harm the assembly. If you tighten the bolt correctly, holding the female part of the bolt with a key while tightening, you shouldn't have a problem with the clamp as it is. 
Depending of how far from the boom clamp you hang the bike in the repair stand, as soon you take the front wheel off, you are indeed going to put quite a bit of torque on the boom clamp assembly. Therefore you should clamp it as close as possible to the steering axle.
 

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Jeremy S's picture
Jeremy S
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Thanks for the feedback.Yes,

Thanks for the feedback.

Yes, I believe the clamp will still work fine as a clamp and the bolt will still tighten down with this minor damage. I do wonder though if the creaking I'm hearing now is from the minor damage. Maybe the right thing to do is just to grease it up good and reassemble, however I have the front end apart to install a chainstay extension provided by a certain forum member, and this seems like a good opportunity to put on a new clamp if I can get one. And yes I did contact Cruzbike support about that.

Doug, my understanding is that the new Silvio 2.2/S30 has a fatter boom so I expect that a clamp from a newer production run would not fit.

Marc, the female end of the bolt has a circular hole, so a hex key will not work if that's what you are suggesting.

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yakmurph
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Grease!

If the greased bolt is silenced, then good.

If you can't replace the boom clamp, or repair it, then
consider replacing the keyed bolt with an un-keyed bolt.

Add a lock washer between the new non-keyed bolt and
a flat washer, reassemble with grease and you're off.

-Steve

 

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Jeremy S's picture
Jeremy S
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You guys were right of

You guys were right of course, a bunch of grease in the right places got rid of the creaking. I'm still going to be extra careful with that bolt/clamp, though.