Minimum seatube insertion on an airborne lancaster

bit twitchy cos i’ve seen all the problems with splits etc from running a too short a seattube….

So i have a 300mm tube from van nicholas, which sits as per the below pic, when at its minimum insertion point of 80mm, about 5mm beneath the top tube.

it just so happens this fits perfectly, but is it enough insertion?

i only do light xc tbh, but am a fairly heavy 12 stone.

Reading the what ti frame thread it appears that the problem is where the internal sleeve ends, any seatpost below that is entirely superfluous, so make sure your post reaches that point.

Agreed with njee20, my Lancaster cracked exactly where the internal sleeve ended despite the seatpost going in much further.

sooooooooo

dyer reckon mine would be ok with light use, and going to the trouble of swapping would be a bit pointless?

i have warranty so is it a case of if its going to crack it will do so anyway?

I dont do any silly jumping or drop off’s bigger than a foot, and to be fair i have a phenom (toupe type) saddle, so that would probably give way before the frame……

I have emailed van nic, but no reply as yet.

Your seat post is too short, you need at least an inch of post below the seatube / toptube junction.

It does look a bit short, as if the end of the seatpost will be transferring stress to the frame right on the weld. But as said above, it also depends if the seatpost is sleeved, and where that ends.

seat tube is sleeved, the sleeve ends a further 30mm below the seattube end, as it is set up above.

?

sorry meant seat tube is sleeved, the sleeve ends a further 30mm below the seat POST…..