Jerry Moos wrote:
>First, someone commented recently about a seat clamp on a bike coming
>"upside down" and the top of a straight post contacting the bottom of
>the saddle.
Could be me. My alter-ego, Carapace Completed Umber refers to this
at: http://sheldonbrown.com/
>I presume he meant the type of clamp with two toothed
>flanges on each side, the whole thing being held together with a single
>bolt through the middle. By "upside down" I think he meant that the
>outside flanges are rotated such that the saddle rails pass below the
>clamp bolt rather than above it. Maybe I've been doing it wrong for
>years, but I always though this "upside down" configuration was the
>correct one.
Nope. You haven't noticed how hard it is to get a wrench on the nut in this upside-down setup?
The upside-down setup is occasionally useful for getting a saddle
extra low to fit a smaller person on a lady's or mixte frame, but it
is definitely _not_ the normal way to set up this type of saddle
clamp.
>The reason I believe this is that on the classic crested
>Simplex seat post which secures the rails in a very similar manner, the
>rails pass below the clamp bolts, although this post has one clamp bolt
>on each side rather than a a single bolt.
The clamp-to-a-straight-post design predates fancy posts like the
Simplex by many, many decades.
>I think the problem with the
>post touching the saddle was that the straight post on that bike did not
>widen below the clamp, not that the clamp was upside down.
That was part of it, but even absent that, normal leather sag can result in bottoming out on the clamp with some leather saddles. This in addition to the difficulty of getting a wrench on the nuts.
A more interesting question to me is whether the bolt should go in front of or behind the seatpost. For any modern ideas of fitting, the bolt needs to go behind the post, but if you look at old illustrations, the saddles were very commonly placed much farther forward, with the bolt in front of the seatpost, or even cantilevered forward on a "7" shaped seatpost with a forward-facing horizontal extension.
Sheldon "Bolt Below" Brown Newtonville, Massachusetts +---------------------------------------------------+ | In theory, there's no difference between theory | | and practice; but, in practice, there is. | +---------------------------------------------------+,
Harris Cyclery, West Newton, Massachusetts
Phone 617-244-9772, 617-244-1040, FAX 617-244-1041
http://harriscyclery.com
Hard-to-find parts shipped Worldwide
http://captainbike.com
Useful articles about bicycles and cycling
http://sheldonbrown.com