18" Kona Hei Hei seatpost size? 27.0 or 27.2?

[KeepItSteel]

I just slipped a 27.0 in my 97 King Kahuna and it seemed a little small....which worries me as ive just won a 27.0 Thomson post on fleabay.

I'll be gutted if I end up needing a 27.2

 

[KeepItSteel]

but then I found this....

http://www.bikepedia.com/QuickBike/Bike ... &Type=bike

 

[stevek]

I just slipped a 27.0 in my 97 King Kahuna and it seemed a little small....which worries me as ive just won a 27.0 Thomson post on fleabay.

I'll be gutted if I end up needing a 27.2

My '98 KK has always had 27.0 pins fitted without any problems. Currently it has a ti Syncros pin, prior to that it had a 27.0 Thomson and before that a 27.0 alu Syncros.

Didn't you believe the great Sheldon Brown in the link I sent earlier up the thread?

 

[letmetalktomark]

I can see where the confusion comes from.....

I know that the websites say 27.0 but if I was being picky I could do with a 27.1 for my frame.

 

[stevek]

I wonder if manufacturing tolerances differ? (Probably?) Is brand 'X' 27.0 seat post truly a 27.0 or perhaps a little bigger / smaller than brand 'Y' 27.0? Does the internal dia of the seat tube really measure 27.0? (Time to get the vernier out!) Does the seat clamp fit correctly...?

 

[KeepItSteel]

Didn't you believe the great Sheldon Brown in the link I sent earlier up the thread?

i guess so, but wouldnt his chart be made up of other people input? not infalable if thats the case

my concern came from the fact that I removed an al Syncros 27.0 post from my 97 Kona a'ha, which is a snug fit, and as I inserted it into the 97 King Kahuna it slipped it without the snug feeling..almost too easy. It also seemed to rattle a tiny amount if moved from side to side until approx 30% of the post was inserted. I would expect this from a post that is slightly too small?....

Its true that my a'ha is steel and probably in fairness a little dirtier internally than the Ti tubing on the KK.
When I tightened the seast clamp nice and tight on the KK there didnt seem to be much of an issue..but the experience left me feeling the ideal size would be 27.2mm

I've read that most frames stating 27.0 can be gotten away with a 27.2, but id rather go for the perfect fit than try to make something fit. I guess i'll have a better idea when the 27.0 Thomson arrives, then ill apologise for doubting Sheldon

 

[stevek]

S'pose you could use one of these?

Seatpost sizing rod, LBS would have one.

 

[Wold Ranger]

Seat post sizes

Just to throw total confusion on the scene, all seatpost brands are different diameters for any given quoted size!!! I.e i have a 98 Lavadome in as new condition, fits a nice Use Ti post with 27.00mm spacer/shim lovely! A 27.00mm Ringle Moby will not fit far too big! An Easton Carbon 26.8 fits perfect with no slop. I also have an FSA 27.2 that fits but is slightely tight. It's not the frame manufacturer very oft, but the seat post maker! I've Micrometered a few seatposts over the years and they can vary by .2mm to the quoted size, which can't be good!

 

[KeepItSteel]

I guess the moral is....there is no correct size!

My case differs to yours in that both my frames are apparently 27.0, but my Syncros 27.0 fits snug/tight in one, and sloppy in the other...

 

[Wold Ranger]

Posts

I find that with Gt's they tend to come up .1mm larger, but next size up won't fit!