Seat Post collar

[D Bell]

Hey folks, I was wondering if anyone knew the seat post size for a 1993 Kona Kialauea. I have a Thomson 27.2 post in it (which is SNUG once it gets to the top tube). The frame is Tange Presitge steel, about a U.S. quarter's thickness. I'd like to replace the old Joe Murray piece but unsure which Thomson/ Salsa size would work. And I have some original parts if anyone's interested, how about them bat wing bar-end brake lever extenders?

Thanks

 

[alfeng]

FWIW. While I cannot tell you the specific Inner Diameter for your frame, 26.8mm was typical on Japanese bikes in the 80s & 90s ...

There ARE exceptions ... Trek used 26.6mm on a lot of their steel frames ...

27.0mm seems less common on Japanese frames until closer to the turn-of-the-Century.

FYI. Because I have found that when a supposedly correctly sized seatpost sometimes SLIPS (on more than one frame), going up to the next size (i.e., 0.2mm larger) eliminates the slipping problem AND the post is snug BUT I can move it easily enough to make height adjustments ...

I have found that a seatpost whose diameter is 0.4mm larger than the specified size is not viable ...

SO, presuming that there isn't an unintended obstruction in the seat tube, then based on what you have said, I reckon your seat tube's Inner Diameter is more than likely 27.0mm ... but, no guarantees.

 

[vspa]

a vernier caliper is capable of measuring inside and outside diameters,