Kevin I have several thoughts on this. First and foremost, I will agree with the several responders who said you deserve to be happy and frustration-free on your new bike. Now, here's a checklist.
1. Tolerances. As others have said, you can measure the seatpost and the hole in the frame to see if they both are exactly 27.2mm. I will assume you don't have the tool to do that. That's OK, the absolute measurement is not as important as the relative measurement, and you have what you need to do that. When the bolt is loose, does the seatpost FALL down into the frame? Is it noticeably rattling inside the hole? If yes, then the seatpost is undersized or the frame is oversized. If the seatpost slides in easily, but does not FALL in, and there is little to no discernible rattle, then you are fine. 2. Interference from the brake hanger. There is a narrow slot between the ears. That slot gets pinched when you tighten the bolt. The brake hanger lives in that slot. If it prevents the ears from being pinched together, then you aren't clamping your seatpost. You are clamping your brake hanger. The test for this is first try to twist your seatpost with the bolt tight. If it is slipping down the way you describe, it should be shockingly easy to move. Assuming that is the case, take the bolt all the way out to free the hanger. Put the bolt back in and tighten it, just normal tightness. Can you still twist the saddle? If yes, move on. If no, that was your problem. Make Riv give you a new hanger that is made from thinner material. These two tests will take you about 10 minutes. Let us know what happens from that. You should not have to resort to knurling or loctite until you know what problem you are solving. Bill Lindsay El Cerrito, CA On Monday, April 27, 2015 at 7:17:04 AM UTC-7, Kevin Lindsey wrote: > > Just finished building my Hunqapillar over the weekend and rode it 20+ > miles to work this morning. Although still too early to tell, it has "my > very favorite bike" stamped all over it. > With one possible exception: I can't get the seatpost to stop slipping > down. Despite tightening the bolt to so hard that the allen hole is > starting to strip, it still inches down as I ride, and we had to stop six > times on the ride in this morning to raise the seat back up. Very > frustrating. I had thought that maybe the brake cable hanger was > interfering with the seat tube somehow, but I don't see how that can be > avoided, given the shape of the hanger and the fact that it has to remain > attached to the seatpost bolt. > Has anyone else experienced this problem? > Best to all, > Kevin > -- You received this message because you are subscribed to the Google Groups "RBW Owners Bunch" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. Visit this group at http://groups.google.com/group/rbw-owners-bunch. For more options, visit https://groups.google.com/d/optout.
