[AlpineArt]

I am on the short side and my seatpost now disappears quite a distance into my seat tube. My seat post is a Ritchey WCS single bolt carbon Fiber. I think I may be able to save some weight by cutting off some portion of the bottom of the post. Question is: how much of the seatpost is required to be in the seat tube to be safe?

 

[been200mph]

IMO anything just below the point where the bottom side of the TT intersects the ST.

 

[Marty01]

I`d add about a half inch to that lenght.. adjustment range thru the cycling season

 

[stevesbike]

1. measure the distance from the min insert line to the bottom before cutting; 2. your min cut line is that distance added to your insertion line. I'd add 2cm just to be on the safe side and have some adjustability.

 

[Juanmoretime]

I go for 100mm inserted. Be careful. Some seatposts are only meant to be clamped within a scale on the post. Anywhere else might not be reenforced to handle the force of clamping.

 

[spastook]

In my experience it's not worth it. Especially a carbon post. Even if you were to hack off 3 inches the weight savings would be negligible maybe 50 grams. I've done it a couple of times and always wound up kicking myself because I could have used that post on another project down the road but now it's too short and I have to cough up another $75-$100 bucks for another post.

 

[skaruda_23]

In my experience it's not worth it. Especially a carbon post. Even if you were to hack off 3 inches the weight savings would be negligible maybe 50 grams. I've done it a couple of times and always wound up kicking myself because I could have used that post on another project down the road but now it's too short and I have to cough up another $75-$100 bucks for another post.

Agreed. I bought a CF post this summer and was considering cutting it. Even started a thread about it. There's better, safer ways to save a few grams that won't leave you kicking yourself later on.

 

[been200mph]

In my experience it's not worth it. Especially a carbon post. Even if you were to hack off 3 inches the weight savings would be negligible maybe 50 grams. I've done it a couple of times and always wound up kicking myself because I could have used that post on another project down the road but now it's too short and I have to cough up another $75-$100 bucks for another post.

It won't be 50g but if you're on a quest to build a lighter bike it all adds up. You just need to make the commitment to doing so and not look down the road for "what if" situations. Have a plan and stick to it. It's worked pretty well for me thus far on 2 bikes. If you're looking at a light part see if you can find a used or closeout one. Then if you positively don't like it chances are good you can flip it and get most if not all of your money back.

 

[stoked]

+1 for not cutting it. Get a light post instead.

Recently purchased KCNC 27.2x400mm Al seatpost for my MTB which can be used on a road bike as well. I could not find 350mm version for similar price on ebay. I was planning on cutting it but it weighed 145g on my scale(158g advertised). Not going to touch it since it is lighter than most carbon posts out there.