Seatpost bolt

[CWM]

Dan

Many thanks.  Your ongoing interest in other people's bicycle problems is appreciated here, and many places elsewhere I am sure. QR a neat idea but I suspect prone to the same issues of the two lugs not being parallel - which I too think they are not.  I could never work out why I could have snapped a bolt, but reading some of the comments above made me think more carefully about the stress on the bolt where it is not being pulled in a straight line. Though I should also acknowledge that the bolts could have been of lower quality, perhaps should have been greased more, etc,  so perhaps some user error involved.

I am tempted to cut the lugs off and be done with the problem. I see what you mean about repeating the strain on the bolt if the new collar gets pulled out of shape.  And hence the clever design of the rotating threaded end.

I feel a bit nervous taking a hacksaw to my precious Thorn frames but I do have the red touch up paint so I suppose it will be fine. If I am careful!

Thanks again

Clive

[mickeg]

... I read of someone removing the braze ons and fitting a free standing collar.  Is that too extreme? ...

I bought my Sherpa frame used.  The previous owner had the seatpost mounting removed and then got a Salsa brand seatpost collar.  Since I never saw the original fitting on the frame, I have no opinion.  He said that he had a frame builder do the work, but I would assume anyone skilled with a hacksaw (which is almost everyone) could do a fine job.  Thus, I would take Dan's advice.  And do it slow, take your time, use a file to clean it up after you cut it.

On my Nomad, I have cut a small slot in the threaded end of the seatpost bolt, so that if the bolt breaks, I should be able to extract it with a small screwdriver. 

I have carried a spare seatpost bolt on tours, but I quit doing that when I realized that my stem cap bolt would substitute nicely.  (Before you assume yours will substitute, check to make sure.)  I have heard that the seatpost bolt breaking is one of the worst bolts you can have break while on a tour, but I have never broken one (yet?).

When I start cutting on something that makes me nervous (like a Thorn frame), I have a goal of taking at least an hour more than I think it should take, that way I try to stop every few minutes and inspect my work to make sure I did not do anything stupid. 

I am sure there are many other good quality seat post clamps besides the Salsa one that I have on my Sherpa.  I also had a very good clamp on my Long Haul Trucker, but Surly changed specifications after mine was made, so I can't recommend the newer Surly clamps as I have never looked at them closely.

Good luck.

Photo is cropped out of a larger photo, shows the Salsa collar on my Thorn Sherpa.

[CWM]

Thank you again for these replies.  By way of an update, my life is mildly pressured just now and as such I have not yet had a spare hour with another in reserve to saw off the lugs.  However,  I have taken out the seat bolts on the two frames worst affected (Audax and RST) and have greased the bolt and the part where the bolt head meets the frame. I am more comfortable having done this that the force required to stop the seat slipping will probably not shear the bolt.

I also removed a relatively unused/newer bolt from my CT, one which is probably original equipment and where the bolt head fits into the lug (others I am using are retro fitted after I broke the originals and now have "oversized" bolt heads that do not within the lug.  The bolt from the CT would not fit onto the Audax - either my amateur arrangements with the bolt head outside the lug have squashed the lips of the lug out of shape, or the bolt could not fit as the two lugs are not any more in line. I suspect the former.

I am off on a wee tour in a month and do not plan any hacksawing before then.  However,  I am taken with the idea of carrying a jubulee clip that will fit around the top of the seat post, including over the lugs, in case of disaster.  the last time I toured with the audax I did break the bolt on a sunny morning in Barnard Castle. The remnant was unscrewed by hand, but I very much like the idea of a screw driver slot in the end of the bolt to allow for extraction. I am also going to use panniers this time and not a saddlebag.  Much as I do love a bit of duck cotton, I feel it all adds to pressure on the seat post and makes adjustment more likely. And the Audax seems to carry two not very heavy panniers rather nicely.