I ALWAYS grease any seatpost - preferably with an anti-seize formulated lubricant. I don't like the idea of later cutting out a frozen alloy post which has become fused into a steel seat tube (incompatible metals just do this over time). There is no reason a greasy seatpost should slip if the size is even "reasonably" close to the correct size... even under my excessive current weight I never have problems. I only see posts slip when they are extremely mis-matched to the seat tube diameter.
I think the "minimum insert line" concept was to help ensure distribution of the gripped area over a greater distance down inside seat tube. In any case, with undersized posts, the post is surely held at only the small area at the top near the binder bolt, and even an apparently "tightened" bolt may not be holding a post securely if the slotted binder area behind the seat tube is closed down too much to close down and securely grip a skinny post.
By the way, there is a simple hand tool found at auto parts stores called a
Lock Ring Pliers (in the US) which pushes it's knurled flattened jaws outward
when gripped. This is useful to help spread apart the top of even a
mis-shaped, over tightened or damaged seat tube while you test how tight or loosely
a seat post will fit when slid farther down into that seat tube. Here is a
typical example: http://www.lislecorp.com/
Bob Hanson, Albuquerque, NM, USA
EPL wrote:
The notion of using a part that is clearly the wrong marked size escapes me. I also don't get why one would grease a seatpost -- parts that rotate need lubrication, not bolted in stationary fixtures, right?
Go easy on the grease, guys!
Emanuel Lowi Montreal, Quebec
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