Subject: facing vs. reaming Posted by: Oggie on December 17, 2003 at 20:29:18: In Reply to: Re: campy record post slips posted by Oggie on December 17, 2003 at 20:18:39:

Message: >>>I have a Campy record carbon seat post that slips in the frame. The frame is a new Mondonico Foco and has been faced/reamed. The inside of the seat tube is clean and measures 27.2. No grease has been added to either post or seat tube. Ive already broken a well greased Campy seatpost bolt. My local LBS said that I might need to switch posts. That sucks when you have a $100+ post that worked great in another frame. Any suggestions? >>Have you tried the frame with a "regular" aluminum post OR a different carbon seat post just to isolate the problem? >>Is it possible that whoever faced & reamed the seat tube over did it? >>If so, all is not lost -- BUT, you'll want to run the quick test with another seat post first. >>If another 27.2 seatpost ALSO slips, then the problem is with the seat tube. Tsk. Tsk. >>The fix will cost you about $5 and a minimal amount of time ... I'll spare you the details, for now. >> >If you want to use the post, you can use the old aluminum beer can shim trick. Just take an aluminum can, cut out a section to wrap around the post without overlapping, insert into frame. If there is too much shim, just reduce its length until it works. A tried and true method. Also works great for crown races that have an i.d. slightly larger than the crown race seat o.d. I think the thickness of the aluminum can is approx .1mm. BTW, seat tubes are reamed (meaning the i.d. is increased to the desired diameter, e.g., 27.2mm), but not faced. Facing is what you do when you want the surfaces of the ends of two tubes to be exactly parallel to each other. For example, the head tube and BB are generally faced so that the bearings contact the races evenly, ensuring optimum bearing life. There is no purpose to facing the seat tube.