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Old 07-04-20, 09:25 AM
  #70  
SJX426 
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Bikes: '65 Frejus TDF, '73 Bottecchia Giro d'Italia, '83 Colnago Superissimo, '84 Trek 610, '84 Trek 760, '88 Pinarello Veneto, '88 De Rosa Pro, '89 Pinarello Montello, '94 Burley Duet, 97 Specialized RockHopper, 2010 Langster, Tern Link D8

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After having a discussion with Drillium Dude, where he encouraged me to include this info, I am going to present some information that may not be of much interest but I want to record it.
It is about the Cinelli 1R Stem on this build. I don't recal the details of how I acquired it but I do know that DD's bikes typically have them. I was unaware of them until he pointed them out several months ago.

like the concept of minimal clamping mechanic showing on a stem. The 1R does this better than most I have seen. This is one of the reasons I like the XA. The 100 to 120 versions are very sleek as an example is the Pinarello.
P1020200, on Flickr

yes it has the goofy plastic part but at least you can color coordinate it. They appear to be popular based on the prices on the bay.

The !R appears to be no less appealing. Upon delivery, it was taken apart, of course. I have been taking things apart since a very young age. I believe my dads Rolex is still in pieces somewhere in storage. Oh, for those that don't know this is the 1R on this build.
P1020200 , on Flickr

the design is much like you might expect. The bolt attaches to a part that has a ramp that pushes on a mating ramp of the clamping part. As you tighten it, the clamp pushes against the HB. In this next picture, you can see the gap at the back between the HB and the Stem indicating clamping pressure.
P1030529 , on Flickr
The clamp is serrated to prevent rotation. It is a cast AL part. This is the failure part.

What kind of failure?
Cinelli1RClamp, on Flickr
These parts were glued together but failed. I cleaned up the parts, dressed the serrations with a jewelers file and reassembled without the broken pieces. I assumed it would work as the part may have less surface area but would still be able to clamp effectively. So far, so good. Knowing its state and using it is a bit disconcerting. You may note the part in the upper right of the photo that is a threaded part that mates with the clamp.

DD had a really good suggestion. 3D print the part in metal. I don't know anyone who can do it and I don't have a whole, undamaged part to use as a model, not to mention my 3D solid modeling license expired 9 years ago.

Another suggestion was to find a really ratty stem for the parts. I found a candidate that was under $30 but the clamp has cracks on the back side.

A third option would be to make one out of steel. The most challenging part to be fabricated would be the ramp feature on the back side.

Well the next step is to wrap the bar.
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