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I have a Bontrager Privateer frame and am finding it difficult to get a decent 27.0 seatpost to fit. Is it possible and safe to ream it out to 27.2mm? It's only 0.1mm in total from the sides...
Gonna be easier to find a decent seatpost unless it's been really poorly made.
I'd actually like to use a retro or current Bontrager seatpost, hence my enquiry...
I have seen a reamer in a shop (which employed me) though I suspect few will have them nor know how to use them to remove metal rather than clean out seat tubes.
AS for safety, ask KB or a framebuilder.
0.2mm is less than 8 thou in old money, not a lot.
Do you have a 27.2mm reamer?
I had a similar problem with my steel frame a bit ago. The seatpost was always a bit tight so I 'improvised' I got a length of 3/8th steel rod & cut a slot across one end, got some medium emery cloth & cut that into strips, making a very flappy 'flap wheel', crimped the flaps in by squashing the end of the rod in the vice, & went to work with the lecky drill a titchy bit at a time, trying the seatpost every few mins until it was a perfect fit. That was probly about 5 years ago, no ill effects.
PS, It took ages!
Rather than reaming, wouldn't it be better or easier to have the seatpost itself turned down on a lathe?
Had an Orange Prestige frame (circa 1990) and the 27.0 post was always slipping so my LBS reamed the tube to take a 27.2mm seatpost...worked fine after that.
Routine Dean - MemberRather than reaming, wouldn't it be better or easier to have the seatpost itself turned down on a lathe?
I like your thinking. That's gotta be the easiest way to go.
Thanks for all the replies.
I'd rather get the frame reamed out as it's for a retro 'theme' build. A 27.0 Syncros would do the job as I'm also using Syncros 1" threaded headset and Synros square taper BB.
If anybody spots a nice retro seatpost, let me know.
I've got one (not for sale) but just letting you know it exists, USE did a 27.0mm Alien. Just another name for you to type into fleabay, maybe a good place to look?
How think are the frame walls? How much of a % of them is that 0.1 mm?
I have a bunch of adjustable reamers that could do the job but I personally would be doubtful about doing it for fear of weakening the frame
wiggle do a 'system ex' seatpost in 27.0 for a tenner, seems a decent enough post, i know its not inwith the retro tyheme but an option,
http://www.wiggle.co.uk/p/cycle/7/System_EX_Alloy_Seat_Post/5360006738/
Frames are thin as **** I wouldn't try it .Just get one the right size ffs
[url= http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=250589853520&ssPageName=STRK:MEWAX:IT ]Retrotastic[/url]
And you can still buy the shims...
As TJ says depending on the seat tube 0.1mm could be 25% of the metal.
Not an engineer (but a physicist) and IMHO you will seriously compromise the structural strength of either the frame or the seatpost by removing that quantity of metal, depending which you decide to modify.
I've got a 27.0 Fred Salmon post but just fancied something a bit nicer...
I've managed to get everything else retro or Bonty, just need to do something with the seatpost.