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Seatpost minimum insertion(8 posts)

Seatpost minimum insertionwes
Aug 19, 2001 12:41 PM
Here's kind or a moronic situation - so bear with me.

A long time ago, to help save some grams on the bike, I cut off a pretty sizeable portion of my seatpost. A few weeks ago I decided to take the thing out for a basic all around overhaul and to check out the inside of the frame. I discovered that I only have 1 3/4 inches of insertion in the seat tube. I know that most manufacturers recommend something like 2.5 inches, but this would obviously be on the liberal side because they want to protect themselves from trouble.

Anyways - before you all tell me just to get a new seatpost (which I will probably consider anyways) does anyone know what the minimum insertion really is?

I have a Ritchey aluminum post in a lugged steel (Ritchey) frame.
re: Seatpost minimum insertionEvan
Aug 19, 2001 2:50 PM
what the manufactor says, they want you alive to buy another post later in life
Sounds like a pretty slim margin of errormike mcmahon
Aug 19, 2001 2:54 PM
New posts aren't that expensive. I'd buy one.
re: Seatpost minimum insertionJohnG
Aug 19, 2001 3:41 PM
If you have any meat on yourself you are probably stressing that top lug quite a bit. I'd consider getting a new SP just to stress the frame less.

JohnG
Is your family complete yet?Spoke Wrench
Aug 19, 2001 5:05 PM
If not, I'd go with the manufacturer's recommendation.
Rule of thumb...Atombomber
Aug 19, 2001 5:19 PM
The bottom of the post should be below the the point where the bottom of the top tube intersects with the seat tube. Depending on the make and model of the frame, this distance will vary. The more post is inside the frame, the more the lever forces are spread over a larger area. Unless you have a cast-iron seatpost, chopping off an inch won't save enough measurable weight. Better to drink that extra cup of java and eat a bowl of branflakes well before the ride, and sit on the throne with copy of your favourite magazine.
By red neck math...Canidraftyou
Aug 19, 2001 5:47 PM
I asked a fellow redneck here in Arkansas just below where the Ozarks begin, and the question to him was asked in this way. If you need a cheat bar to break open a lug nut, what would be the min. length for an advantage, and he said one third of the cheat bar should be covering the wrench. So my guess would be, if you have 4 inches above the frame of the bike then 2 inches would be enough, but would not go less than that. The "1/3 rule."

Peace out,
re: Seatpost minimum insertionwes
Aug 19, 2001 5:54 PM
ok everyone. Thanks for the responses. Pretty much what I expected to hear.

I actually did go out and get a new seatpost about a week ago. This morning before I posted the original message, I actually put the old (short) post back in.

The problem is that Ritchey takes a 26.8 seatpost. Not the usual 27 or 27.2, so they are pretty hard to find. My "new" post is a 26.8 but it's a Kalloy and the top of the clamp doesn't match (is wider) the bottom of the clamp. In other words, the rails of my Flite makes horrible creaking sounds with every pedal stroke when I'm in the saddle - which is about all the time.

Anyways, thanks for the post and I'll keep looking for a new one. I guess Excel would be a good place to look since they sell Ritchey frames.