How to extend an Integrated Seat Post?

[purpletezza]

A friend of mind bought a frame with a cut Integrated Seat Post(ISP) and it is a couple of centimetres too short. A seat post topper did not come with it. How can he make the ISP taller? The internal diameter of the frame's seat tube is 31.6mm(std seat post diameter). The seat tube is round, not oval or aero.

Suggestions thus far:
1. Get a seat post topper from Ritchey/FSA/Dedacciai. Where from?
2. (Last resort) Cut the seat tube, cut a vertical slot for compression and use a conventional seat clamp to hold a 31.6mm seat post in it. Not sure if the inside of the seat post is clean enough to accept a seat post though.

Any further ideas/recommendations??

 

[Martin318is]

1. sounds reasonable
2. sounds very very risky.

my first thought though is "call the manufacturer" or at worst the distributor

 

[Notso Swift]

or 3, buy longer cranks!

Frame brand?

Also ...are you sure the post is round

 

[ElChingon]

A friend had a similar issue but it was way too short for him, so the vendor recommended cutting the ISP down to a few cm from the top tube/seat tube junction and then cut a half centimeter long gap like a regular non ISP seat tube/seat post bike for the clamp to be able to tighten down on the post. Then just use a regular seat post of the right size for the post.

Of course consult with your bike frame manufacture for the details on what they know works or should work. The above is a short excerpt of what a friend did which was more detailed and scary due to the price of the frame but it all worked out.

 

[Notso Swift]

Look has a "Conversion Kit", for this exact senario, but do not know if others do or if it could cause an issue later as there is a leaver (the sseat post) working against some thing that wasn't designed to take that force in the first place

 

[Michielveedeebee]

just use spacers....