Seatpost/ frame- strange query...

Dustine

Ok, i have had to buy a new micro adjust seatpost for an old frame. The original seatpost was 22mm, inside a 1 1/4" long shim to take it out to the seat tube size of 26.4mm. The only part of the seatpost supported is the bit inside the shim, none of the rest of it touches the sides. The new seatpost will only go 2" down the seat tube, as the seat tube appears to taper beyond the lug. This is however, more than the shim used to hold. 2" takes it beyond the lug, in any case. My query is, can i safely saw the seatpost to length and run it with the 2" in the frame, or is something going to break?? By my reckoning it should be MORE supported now than before.
In the same way, i have a 25mm USE carbon post in another frame, with a shim to take it out to 27.2mm, which is also only a couple of inches long, and thats how they are meant to fit- is that really safe then??

Monty Dog

3x diameter is ideal, but as you stated, anything longer than the shim is pretty well redundant.