Min. seatpost insertion below bottom TT weld

[spartanKid]

What's the general consensus for how far below the bottom seat tube/top tube weld the end of a seatpost should be? 2"? 1"?

The reason I ask is because I just got a specialized allez frameset, and it comes with an OEM post with a min. insertion length of 95 mm, while a Thomson, for example, has a min. insertion length of 63.5 mm. This is for a 27.2 mm OD post.

The OEM post results in having the end of the post be almost 2" below the bottom weld, and likewise, a 63.5mm insertion length from a Thomson would have the end of the post less than an inch below the bottom weld.

What do you all think?

[Peter P.]

Insertion below the weld should 1x-2x the I.D. of the seat tube.

[oldpotatoe]

What's the general consensus for how far below the bottom seat tube/top tube weld the end of a seatpost should be? 2"? 1"?

The reason I ask is because I just got a specialized allez frameset, and it comes with an OEM post with a min. insertion length of 95 mm, while a Thomson, for example, has a min. insertion length of 63.5 mm. This is for a 27.2 mm OD post.

The OEM post results in having the end of the post be almost 2" below the bottom weld, and likewise, a 63.5mm insertion length from a Thomson would have the end of the post less than an inch below the bottom weld.

What do you all think?

Twice the width of the top tube below that weld. General rule of thumb. Twice the width of the top tube below the bottom of the top tube.

[pbarry]

Good advice above. Don't play the margins on this.

[spartanKid]

Thanks everyone!