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What's the absolute minimum amount of seatpost that is safe to have in the seat tube?

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What's the absolute minimum amount of seatpost that is safe to have in the seat tube?

Old 06-07-08, 09:47 PM
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What's the absolute minimum amount of seatpost that is safe to have in the seat tube?

Just wondering what the minimum amount of seat post I can safely have in the seat tube? If a seat post if listed as 250mm, is that 250mm from the top to the minimum insertion line?
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Old 06-07-08, 09:57 PM
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look on the bottom of the post and make sure the safe mark is not showing. That would be the amount.
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Old 06-08-08, 12:37 AM
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About 2-1/4" for a road bike, 3" for a mountain bike.
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Old 06-08-08, 12:44 AM
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Originally Posted by bellweatherman
Just wondering what the minimum amount of seat post I can safely have in the seat tube? If a seat post if listed as 250mm, is that 250mm from the top to the minimum insertion line?
The length of the seat post is generally measured from the saddle clamp to the very end, which includes the part that must be in the frame. A 350mm post I have has about 100mm between the minimum insertion line and the end, so the saddle rails could only be up to 250mm above the seat tube.

Last edited by JiveTurkey; 06-08-08 at 12:51 AM.
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Old 06-08-08, 12:52 AM
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Look at the frame.

The bottom of the post should be below the bottom weld (if a metal frame, of course) on the toptube. Any less and you risk snapping the top of the seattube off.
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