[AlanS]

I want to cut my seat post. What's the "rule" about how much must be in the seattube? I have 3" exposed...the bottom of the intersection of the ST/ TT and seatstays is 3-1/2" from the top of the collar...I have, now about 7" in the seattube...I am sure I can hack some of this off... What is the "rule"???

 

[split]

Hmmm, never heard of an exact rule. I think it depends on the make/model of the seatpost and the make/model of your frame. Sorry, didn't really help. What kind of post and frame do you have?

 

[jeremyb]

check my reply over at mtbr....

 

[daneil]

The rule when cutting a seatpost is to make sure that you have enough post inserted so that the seat post passes the seat tube/top tube junction.

 

[FlyingYeti]

Okay, I think here's the best answer. Most seatposts come with a mark that says "minimum". Measure from the bottom of seatpost to this marking, and this is how much you need to have your post inserted to your seat tube all the time. Thus, get your saddle in position to determine the minimum length you need to keep, then cut off the remainder. I'd leave an inch or so extra just to allow adjustments that may be needed when getting a different saddle.

 

[split]

FlyingYeti's reply seems to make sense. I asked for make and model because I know Giant bikes require 4" into the frame if you use the shim, 6" without a shim, per warranty department.