Getting a drop post machined down - goer or no?

doctorstewie

Senior Retro Guru
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Hi All, I suppose this should be in the post 97 section, but more people look at this section and I could do with a very informed opinion:

I have a new to me full susser that I really want to put a drop post into but it has a seatpost size of 27.00mm.
The only sizes I can find are 27.2 or 30.9.
Would it be stupid to have the outside of a drop post machined down the 0.2 mm? Would it make the post dangerously weak?

Cheers All
 
Depends on thickness and material. I suspect it's aluminum. But how thick is the tube?

Another option is to ream the seat tube out. That's probably lower risk, as the loads are better suited to thinning the walls.
 
Re:

Ream the seat tube.

Any modifications to your dropper post will invalidate any warranty and probably make servicing it slightly more troublesome.
(It will need servicing, they all do soon enough)

Reaming out a seat tube on the other hand will be cheaper, safer and far more reliable. Plus it'll open up more options for seatpost replacements in the future. (When your dropper post breaks)

(Moved to 97 onwards btw...)
 
Last time I had a good reaming it cost me about 20 quid at a frame shop.
I had a less satisfactory reaming at an LBS for free.

Never had the sort of reaming k-rod seems to be so well informed about. ;)
 
Re:

Gravity Dropper makes a 26.8mm post but any shim would be so flimsy it might not work. I went through the same thinking and decidd to have my Spooky Bandwagon reamed from 26.8mm to 27.2mm and it has been fine.
 
Re:

.. or buy a set of reamers for £140 but for a one off, be cheaper to get a shop or frame builder to do it.
 
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